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| موضوع: كتاب Glossary of Valve Terms الأحد 28 أغسطس 2022, 2:15 am | |
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أخواني في الله أحضرت لكم كتاب Glossary of Valve Terms
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Contents Section 1 Valve Terminology 1 Engineered Surge Relief Systems 85 Conversion Tables and Equivalents 88 General Information 107 SECTION 2 SECTION 3 SECTION 4 AGA - American Gas Association AISI - American Iron & Steel Institute ANSI - American National Standard Institute API - American Petroleum Institute API SPEC 6FA API SPEC 6D/ISO 14313 ASME - American Society of Mechanical Engineers A society comprising gas companies set up to achieve common goals. An association of steelmakers which sets standards for the chemical and physical properties of steel and iron in various shapes and forms - pipe, tubing, sheet, strip, wire The principle organization in the US which oversees the creation, promulgation and use of standards for a wide variety of items, including the design, fabrication, and testing of pressure piping, systems, and components for various pipeline services. The principal US oil company trade association. It has some standards and specification writing functions, such as wellhead components and pipeline valves The API specification dealing with the fire testing of pipeline valves. Once a particular size and pressure class valve is tested and passes the API fire test, all such valves can be identified with the above monogram. API-6FA supersedes API-RP-6F. An API specification dealing with pipeline valves. Most pipeline valves are manufactured to this specification and, if so, can be identified with the API 6D monogram This professional society publishes technical books, papers, codes and standards. Of principal interest is the ASME Boiler and Pressure Vessel Code which is referenced for many aspects of valve making. . . . SECTION 1 VALVE TERMINOLOGY 12 VALVE TERMINOLOGY ASTM - American Society for Testing & Materials A professional society governing the detailed physical and chemical analysis of all basic metals and alloys used in construction. The valves of most manufacturers have components whose materials correspond to ASTM standards. AWS - American Welding Society ACCUMULATOR ACME THREAD ACTUATOR ADAPTER SPOOL A society which sets guidelines and standards for all welds. A vessel in which a gas is trapped and compressed by the liquid in a hydraulic system, thus storing energy to supply liquid under pressure to the system when needed. A flat-topped screw thread for power transmission. This thread has a 29° included angle between adjacent thread faces compared with the 60° angle of the US standard “V” thread See “Operator”. An extension which is added to a short face-to-face valve to conform to standard API 6D face-to-face dimensions. . ADAPTER SPOOL SHORT PATTERN GATE VALVE WITH ADAPTER SPOOLALL WELDED CONSTRUCTION Pertains to a valve construction in which the body is completely welded and cannot be disassembled and repaired in the field. VALVE TERMINOLOGY 3 ALL WELDED CONSTRUCTION (NO BOLTED BODY PARTS) AMBIENT TEMPERATURE ANCHOR PIN The prevailing temperature of the environment immediately surrounding an object. A pin welded to the body of a ball valve. This pin aligns the adapter plate and keeps the plate and gear operator from moving while the valve is being operated. ANCHOR PIN CAMERON FULLY WELDED BALL VALVE 4 VALVE TERMINOLOGY ANGLE VALVE A variation of the globe valve in which the end connections are at right angles to each other, rather than being in-line. ATMOSPHERIC PRESSURE BBL (bbl) The external pressure exerted on a body by the atmosphere: 14.7 psi (absolute) at sea level. An abbreviation for “barrel”. Used to express liquid volume. One barrel of oil is equal to 42 US gallons. ANGLE VALVEBDV - Blow Down Valve A small ball valve that is installed on the aboveground end of an extended drain line. This valve also serves to vent body cavity pressure in the “block-and-bleed” mode. See “Block-and-Bleed”, “Extended BDV”. VALVE TERMINOLOGY 5 BGO - Bevel Gear Operated (or Operator) The actuation of a valve by means of a set of bevel gears having the axis of the pinion gear at right angles to that of the larger ring gear. The reduction ratio of this gear set determines the multiplication of torque achieved. Used on gate valves. BDV EXTENSION BGO BALL VALVE WITH DRAIN LINE EXTENSION GATE VALVE WITH BGO BEVEL GEAR6 VALVE TERMINOLOGY BRV - Body Relief Valve A relief valve (optional) installed on ball valves used in liquid service to provide for the relief of excess body pressure caused by thermal expansion. BS 6755 BVR - Ball Valve Regulator The British Standard specification dealing with the fire testing of pipeline valves. Once a particular size and pressure class valve is tested and passes the BS 6755 fire test, all such valves can be identified with the BS 6755 standard. An automatic throttling valve controlling flow or pressure in a pipeline comprising a package involving a ball valve, actuator, positioner, and controlling instrument. BODY RELIEF VALVEBACK PRESSURE REGULATOR BACK SEAT BALL BALL VALVE Regulator designed to control upstream pressure. See “Regulator”. A shoulder on the stem of a valve which seals against a mating surface inside the bonnet to permit replacement, under pressure, of stem seals or packing. The spherical closure element of the ball valve. A valve using a spherical closure element (ball) which is rotated through 90° to open and close the valve. VALVE TERMINOLOGY 7 GROVE B5 BALL VALVE 8 VALVE TERMINOLOGY BAR BDV BELLEVILLE SPRING BENDING MOMENT BEVEL BLOCK-AND-BLEED A metric unit of pressure. One bar equals 14.5 psi. A BDV is also a valve or a system of valves which, when activated, initiate a blowdown of a pipeline, plant, process, or platform; like an ESDV that shuts in a line, except the BDV opens a line. A spring resembling a dished washer, used in some ball valves to push the seats against the ball. The mechanical bending load produced by a force applied to a part at a right angle to its surface or axis. The product of the force times the perpendicular distance to the point of restraint. Usually expressed in pound-feet A chamfer. The angle between two adjacent surfaces (other than 90°). The word “bevel” is used in describing weld-end preparations. See “End Bevel”. The capability of obtaining a seal across the upstream and downstream seat rings of a valve when the body pressure is bled off to the atmosphere through blow down valves or vent plugs. Useful in testing the integrity of seat seals and performing minor repairs under pressure. .BOLT BOLT CIRCLE A fastener which has a square or hex head and is threaded on the opposite end to receive a nut. Sometimes used to make up a flanged connection. The circle on which bolt holes are located. VALVE TERMINOLOGY 9 GROVE G4N GATE VALVE BODY BOLT CIRCLE BOLT CIRCLE DIAMETER BOLTED BONNET A bonnet which is connected to a valve body with bolts. GROVE B4 BALL VALVE 10 VALVE TERMINOLOGY BOLTED CONSTRUCTION Describes a valve construction in which the pressure shell elements are bolted together, and thus can be taken apart and repaired in the field. BOLTING SETS Bolts or studs and nuts sometimes supplied with flanged valves to install the valve between line flanges. BODY CLOSURE BOLTED TO BODY CLOSURE GROVE B4 BALL VALVE BORE (or PORT) BRINELL HARDNESS NO. The inside diameter of the smallest opening through a valve. The diameter of the hole in the ball of a ball valve. The diameter of the hole in the gate of a gate valve. The inside diameter of seat rings. A number indicating metal hardness using the Brinell scale. Can be converted to Rockwell B & C hardness by reference to conversion tables. See “Rockwell Hardness No”. A phrase used in describing the sealing ability of a valve. During air pressure testing of a new valve in the closed position, leakage past the seats is collected and bubbled through water. To qualify as “bubble-tight”, no bubbles should be observed in a prescribed time span. BUBBLE-TIGHT SHUTOFF VALVE TERMINOLOGY 11 BONNET BONNET The top part of a valve, attached to the body, which guides the stem and adapts to extensions or operators. GROVE G4N GATE VALVE RING-O DOUBLE EXPANDING GATE VALVE
BONNET12 VALVE TERMINOLOGY BURIED SERVICE BURST PRESSURE BUTT WELD ENDS BUTTERFLY VALVE An application in which valves are installed in lines which are buried below ground level That pressure (psi) at which rupture of a stressed element or pressure-containing vessel takes place. See “Ultimate Strength”. The end connections of a valve, suitably prepared for butt welding to connecting piping. See “WE”, “End Bevel”. A short face-to-face valve which has a movable vane, in the center of the flow stream, which rotates 90 as the butterfly valve opens and closes. . ° WKM DYNACENTRIC HIGH PERFORMANCE BUTTERFLY VALVE BYPASS A system of pipes and valves permitting the diversion of flow or pressure around a line valve. VALVE TERMINOLOGY 13 C-PACK C.I.F. - Cost Insurance & Freight A special stem packing designed by GROVE to give maximum lifetime sealing in gate, ball and check valve stems. Shipper pays all freight and insurance charges. Same as FOB Destination.
BYPASS OPERATOR BYPASS BALL VALVE GRADE RISER EXTENSION MAINLINE VALVE BURIED VALVE SETTING14 VALVE TERMINOLOGY C CWP - Cold Working Pressure CAPACITY FACTOR CAPSCREW CAST CASTING CAVITATION CERTIFYING AUTHORITY (CA) CHAIN WHEEL OPERATED VALVE v The capacity factor of a valve, also called the valve coefficient; specifically, the number of gallons of water per minute that will flow through a valve with a pressure drop of 1 psi See “MWP”. See “C”. A fastener with a head whose shank is normally threaded throughout its entire length. It is not used with a nut, but rather engagement is made with a female thread in the piece to be joined. The form of a particular part of a valve, where the basic shape is formed by molding rather than fabricating. A part which has been formed by pouring molten metal into a mold. The rapid formation and collapse of vapor pockets in a flowing liquid in localized regions of very low pressure - often a cause of erosive damage to pumps, throttling type valves and the piping itself. Can be the cause of excessive noise. An independent body appointed by the purchaser to carry out a survey of the equipment and/or materials that they are buying. It is the responsibility of the supplier to provide the CA with information, documents, access to works and personnel to enable the survey to be carried out An overhead valve operated by a chain drive wheel instead of a handwheel . . . (or CERTIFICATION)CHARACTERIZED GATE OR BALL CHARPY TEST A ball or gate, the shape of whose port has been specially altered to provide a specific throttling capability. A mechanical test conducted on a precisely machined coupon of the steel to be tested. The coupon is clamped in a special machine and subjected to a lateral hammer blow. This test provides a relative measure of the toughness of the steel or its resistance to shock or impact loads. Often required for low temperature applications where testing is done at the expected minimum service temperature. (Refer to Table 3.8 of API 6D.) VALVE TERMINOLOGY 15 CHECK VALVE A one-directional valve which is opened by the fluid flow in one direction and which closes automatically when the flow stops or reverses direction. See “Clapper”. VEE NOTCH TEST COUPON IS SHAPED LIKE THIS TOM WHEATLEY SWING CHECK VALVE TM16 VALVE TERMINOLOGY CHEVRON PACKING A type of packing used in packing boxes consisting of a nest of “V” cross-section rings. CITY GATE (or CITY GATE STATION) CLADDING The metering and pressure-reducing station where gas is transferred from a high pressure cross-country transmission line to a low pressure distribution piping system within a city. A method of coating metals by which the coating becomes an integral part of the material. This can be done by casting or hot working. It is generally done on valves where special trims are required for difficult applications. CHEVRON PACKINGCLAPPER The hinged closure element of a swing-disc check valve. VALVE TERMINOLOGY 17 CLASS A designation of pressure capability. See “ASME”, “MWP”. A “U” shaped connecting yoke at the end of a stem or rod, between the ends of which a gate or other part may be pinned or bolted. CLEVIS CLEVIS CLEVIS PIN CLAPPER TOM WHEATLEY SWING CHECK VALVE TM18 VALVE TERMINOLOGY CLOSURE The end of a ball valve bolted to the body, which often contains the seat rings. Often referred to as part of the body. CLOSURE ELEMENTS COAL GASIFICATION COMPRESSOR CONCENTRIC The moving part of a valve, positioned in the flow stream, which controls flow through the valve. Ball, Gate, Plug, Clapper, Disc, etc., are specific names for closure elements The process of manufacturing natural gas from coal. A device which converts mechanical energy into gas pressure. Having the same centers. . CLOSURE SEAT O-RING TWO DIAMETERS ON SAME CENTERLINE CONCENTRIC REDUCERCONTAMINANT CONTROL VALVE A particle or material which is foreign to the fluid media. A valve that controls a process variable, such as pressure, flow or temperature, by modulating its opening in response to a signal from a controller. See “Controller”. VALVE TERMINOLOGY 19 CONTROLLER A device that measures a controlled variable, compares it with a predetermined setting and signals the actuator to re-adjust the opening of the valve in order to re-establish the original control setting. The deterioration of a material due to chemical action. Of or using runners or slides as a guiding mechanism, as in a “Coulisse” style gate valve Unrefined oil. Oil as it comes directly from the well. CORROSION COULISSE CRUDE OIL . VALVE CONTROL VALVE CONTROLS20 VALVE TERMINOLOGY CRYOGENIC TEMPERATURE CRYOGENIC VALVE CYCLE CYCLE TEST CYLINDER OPERATOR Any temperature below about -240°F (-151°C). A valve capable of functioning at cryogenic temperatures. A single complete operation or process returning to the starting point. A valve, stroked from full open to full closed and back to full open, has undergone one cycle. A procedure whereby a product is put through an interval of time during which a test process is completed. This can be a set number of events or it can be a continuous operation until something in the product fails. A power-piston valve operator using either hydraulic or pneumatic pressure. A sealed piston converts applied pressure into a linear piston rod (stem) motion. See “Power Operator”. POWER-PISTON VALVEVALVE TERMINOLOGY 21 DIFFERENTIAL PRESSURE The difference in pressure across a valve in a pressurized line. The difference in pressure between any two points in a pressurized system under flowing conditions. RESTRICTING ORIFICE AIR DOME POWER CHAMBER DIAPHRAGM VALVE STEM AIR-DOME REGULATOR DIAPHRAGM DPD - DOUBLE-POLE DOUBLE-THROW Related to electrical switches. See “SPDT”. Related to electrical switches. See “SPST”. See “Differential Pressure”, “Pressure Drop”. A procedure by which a certifying authority, appointed by the purchaser, appraises the design parameters of the equipment and/or materials they are buying. The supplier shall submit drawings, calculations and documents as required to the CA, in conjunction with those normally required for review and acceptance by the purchaser. A round, thin, flexible sealing device secured and sealed around its outer edge - and sometimes around a central hole in the diaphragm - with its unsupported area free to move by flexing. DPST - DOUBLE POLE SINGLE-THROW DELTA ( P) DESIGN APPRAISAL DIAPHRAGM D22 VALVE TERMINOLOGY DIP TUBE Extending the blow down valve on large gate valves requires a tube which is located inside of the valve. This tube is called the “dip tube” and extends through the bonnet to the bottom of the body cavity. DISC DISTRIBUTION LINE DOT REGULATIONS - Department of Transportation The closure element of a globe angle or small regulator valve. The disc (sometimes referred to as a “valve”, “poppet”, or “plug”) moves to and from the seat in a direction perpendicular to the seat face Depends on stem force for tight shutoff Pipeline which distributes gas to the service lines of individual consumers. Usually it is small in diameter (6” and under) and low pressure (under 150 psi). A code of federal regulations setting forth minimum safety requirements for the transportation of hazardous gases or liquids by pipeline. . . ½” DIP TUBEDOUBLE-BLOCK-AND-BLEED A valving arrangement which ensures no flow in a line, even though the valve may leak. It consists of two block valves in the main line with a small bleeder valve draining the line between the block valves. See “Block-and-Bleed”. “DOUBLE” PISTON EFFECT PRINCIPLE (DPE) The sealing principle of GROVE ball valves whereby line pressure is used on both upstream and downstream floating seats to effect a dead-tight seal simultaneously on both sides of the ball. With the DPE seat configuration, when the upstream seat leaks, the pressure entering into the body cavity acts on the downstream seat, which, being of the DPE design, is then pushed against the ball, and the valve seals in both directions
. VALVE TERMINOLOGY 23 DRAIN PLUG A fitting at the bottom of a valve, the removal of which permits draining and flushing of the body cavity The vent plug assembly on some ball and gate valves also serves as a drain valve. See “Vent Plug”. . UPSTREAM BALL DOWNSTREAM LINE PRESSURE HIGHER THAN BODY PRESSURE BODY PRESSURE HIGHER THAN LINE PRESSURE SEALING DIAMETER X A2 A > 2 A BY AMOUNT X 1 A > 2 A BY AMOUNT X 1 A2 X DOUBLE PISTON EFFECT PRINCIPLE SEALING DIAMETER24 VALVE TERMINOLOGY DRIVE PINS The two pins which fit into the bottom of a ball valve stem and engage corresponding holes in the ball. As the operator turns the stem, the drive pins turn the ball. DROOP DRY LUBE DU BEARING A drop in set (outlet) pressure of a regulator or control valve due to the travel of its valve or poppet as the required flow increases from low to maximum. A slight change in the control spring length due to the valve travel will result in spring force variations, translating into a change of set (outlet) pressure. Dry-film moly disulphide applied as a coating to sliding or rotating parts to reduce frictional drag. After application, the film is baked in an oven at high temperature. A bearing consisting of bronze impregnated with TFE (Teflon) resin which is lead powder-bonded to a low carbon steel backing. A Garlock Company product. “ “ STEM DRIVE PIN HOLES IN BALL BALL DRIVE PINSVALVE TERMINOLOGY 25 ELASTOMER A natural or synthetic material. Used in synthetic rubber parts such as O-rings. A female-threaded or socket fitting used for changing direction in a run of pipe or tubing. See “Ell”, “Street Ell”. ELBOW DUROMETER DYE PENETRANT INSPECTION EMO - Electric Motor Operated ESDV - Emergency Shutdown Valve ECCENTRIC An instrument for determining the hardness of synthetic rubber or elastomeric materials, usually on the Shore A scale. Also the unit of hardness: i.e., ”90 Durometer Shore A”. See “Liquid Penetrant Inspection”. The actuation of a valve by electric motor. See “Power Operator”. A valve or a system of valves which, when activated, initiate a shutdown of the plant, process, or platform they are tied to. Not having the same center. CENTERLINES ARE OFFSET ECCENTRIC REDUCER 90° ELBOW 45° ELBOW26 VALVE TERMINOLOGY ELECTROLESS NICKEL PLATING ELL EMERGENCY SEAT SEAL A plating process which requires no external electrical power and is the result of a chemical reaction between the part and the plating solution. A uniform consistent deposit and plating rate can be produced by controlling and adjusting the chemistry of the plating bath. A pipe or tubing fitting that has the shape of an “L”. See “Elbow”. To obtain tight shutoff in an emergency situation, a sealant can be injected into a specially designed groove in the seat rings. Available for most ball valves and gate valves. EMERGENCY SEALANT INJECTION FITTING BODY BALL VALVE GATE VALVE TO LUBE ASSEMBLY IN BONNET SEAT BODY SEALANT PASSAGE SEAT BALL SEALANT PASSAGE GATEVALVE TERMINOLOGY 27 END BEVEL Weld end preparations for butt welding. Governed by ASME B31.4 and B16.25. END CONNECTION EROSION EXPANDING GATE VALVE EXPLOSION PROOF The type of connection supplied on the end of a valve which allows it to be installed in a pipeline. Weld end, flanged end, screwed end. The mechanical wearing away of a metal surface or part due to fluid impingement. The presence of entrained solid particles accelerates this process. A gate valve comprised of a separate gate and segment that, as the valve operates that gate and segment, move without touching the seats, permitting the valve to be opened and closed without wear. In the closed position, the gate and segment are forced against the seats. Continued downward movement of the gate causes the gate and segment to expand against the seats. When the valve reaches its full open position, the gate and segment seal off against the seats while the flow is isolated from the valve body. The prevention of explosion triggered by electrical components through containment in special housings. A requirement for electrical devices, such as solenoids and switches, when exposed to a potentially explosive environment. WELD END BEVELS 1/16" ± 1/32" 37 1/2° ± 2 1/2° 3/4" 10° ± 1° T 37 1/2° ± 2 1/2° 1/16" ± 1/32" 1 1/8" R. Min.28 VALVE TERMINOLOGY EXPORT PACKING EXTENDED BDV - Blow Down Valve Special packing and crating that is required for export shipping. Includes sealing against a salt atmosphere (sea air). Used on buried valves where the drain plug is inaccessible. Instead, a line is piped above grade, terminating in a small valve. Line pressure is used to blow out condensates and other material which settles out in the bottom of the body cavity. See “BDV”. BDV EXTENDED BLOW DOWN LINE BALL VALVE GATE VALVE BDV EXTENDED BLOW DOWN LINEVALVE TERMINOLOGY 29 EXTERNAL COATING FAS - Free Along Side FE - Flanged End FEA - Finite Element Analysis FERC - Federal Energy Regulatory Commission Coating applied to protect valves against various environments - sea air, salt water, earth burial, and normal air exposure. Term used for ocean shipment. Vendor pays transportation only to shipping dock alongside vessel. See “RF”, “RTJ”. State-of-the-art method of analyzing complex shapes by organizing the shapes into a series of smaller elements which can be more accurately analyzed to determine whether or not components are suitable for their intended purpose. A United States government agency which has the final approval of new pipelines, right of ways, etc. EXTENSIONS GATE VALVE BALL VALVE EXTENSION STEM The equipment applied to buried valves to provide above-grade accessibility to operating gear, blow down, and seat lubrication systems.30 VALVE TERMINOLOGY FOB - Free On Board FPC - Federal Power Commission FABRICATED VALVE FACE-TO-FACE Transportation charges are absorbed by vendor to the FOB point. Usually a shipment is FOB Factory, in which case, title, and transportation charges pass to the customer when it leaves the factory. The United States government agency which governs and regulates the natural gas and pipeline industry, as well as other energy industries. One in which the body and hub parts are not cast, but rather are formed from plate or pipe and then welded or bolted together. The overall dimension from the inlet face of a valve to the outlet face of the valve (one end to the other). This dimension is governed by ASME B16.10 and API 6D to ensure that such valves are mutually interchangeable, regardless of the manufacturer. FACING The finish of the contact surface of flanged fittings. DIMENSION E IS FACE-TO-FACE LENGTH “ “ EVALVE TERMINOLOGY 31 FAIL SAFE VALVE FATIGUE ASSESSMENT FEMALE THREAD FIELD SERVICEABLE FIRE GATE FIRE SAFE FITTING A valve designed to operate to a preferred position (open or closed) in order to avoid an undesirable consequence in a piping system. Refer to ESDV and BDV. Fatigue resistance verification of a component subjected to a number of operating cycles. An internal screw thread designed to mate with a component having male (external) threads of the same size and type. A statement indicating that normal repair of the valve or replacement of operating parts can be accomplished in the field without returning the valve or part to the manufacturer. A gate or ball valve which is positioned in a pipeline at the entrance to a compressor station. This valve is closed in case of fire in the compressor station. Closing the valve prevents the gas in the pipeline from feeding the fire. A statement associated with a valve design which is capable of passing certain specified leakage and operational tests after exposure to fire. Must be referenced to a particular specification. See API Spec 6FA and BS Spec 6755. Any device used for connecting elements in fluid lines, i.e., elbows, tees, nipples, unions, flanges, etc.32 VALVE TERMINOLOGY FLANGE A cast or formed pipe fitting consisting of a projecting radial collar with bolt holes to provide a means of attachment to piping components having a similar fitting. The end piece of flanged-end valves. FLEXFLO FLEXIBLE TUBE VALVE
The registered trademark of a flexible tube valve manufactured by CAMERON. A special valve using a flexible sleeve or tube which acts as the closure element. Pressure applied to the jacket space surrounding the outside of the tube that controls the opening and closing of the valve. FLOATING BALL FLOW FLOW COEFFICIENT . . A ball valve having a non-trunnion mounted ball. The ball is free to float between the seat rings and thus causes higher torques. A fluid in motion in a conducting line. The number of gallons of water per minute that will flow through a valve with a pressure drop of 1 psi Also referred to as the C of the valve v FLEXIBLE TUBE VALVEVALVE TERMINOLOGY 33 FLOW, LAMINAR FLOW METER FLOW RATE FLOW, TURBULENT FLUID FORCE FORGING FRICTION FULL BORE The flow of a viscous fluid in which the fluid moves in parallel layers with a fixed velocity gradient from the centerline to the containing walls of the conduit. Sometimes referred to as streamline flow An instrument used to measure flow rate or total flow or both. The volume or weight of a fluid passing through a pipeline or conductor per unit of time, i.e., 3000 barrels of oil per day; 4 MMCF of gas per hour. The random flow of a fluid in which the velocity at a certain point in the fluid varies irregularly. Any non-solid substance that can be made to flow. Both liquids and gases are fluids. The intensity of an influence tending to produce motion, distortions or change of shape. The product of unit force (psi) and the area over which it acts. Usually expressed in pounds. A part that is formed by heating and hammering to a specific shape. The resistance to motion between two contacting surfaces or substances. Friction is also developed between a flowing fluid and the inner wall of the conducting pipe - resulting in a drop in pressure See Full Opening . “ “ “ “ . .34 VALVE TERMINOLOGY FULL OPENING FULL PENETRATION WELD Describes a valve whose bore (port) is nominally equal to the bore of the connecting pipe. See Venturi Valve . Describes the type of weld wherein the weld metal extends across the entire wall thickness of the joint. “ “ GO - Gear Operated The actuation of a valve through a gear set which multiplies the torque applied to the valve stem. See BGO - Bevel Gear Operator , MGO - Manual Gear Operator". “ “ “ WALL BEVEL GEAR OPERATOR FULL PENETRATION WELD WORM GEAR OPERATOR BEVEL WORM DRIVE GEARVALVE TERMINOLOGY 35 GALLING GAS GASKET GATE GATE VALVE The tearing of metal when two elements rub against each other. Usually caused by lack of lubrication or extreme contact pressure. A compressible fluid such as air, hydrogen, nitrogen, etc A seal or packing placed between mechanical joints (such as flanges) to prevent the escape of the flowing medium. The closure element of a gate valve. A straight-through pattern valve whose closure element is a wedge or parallel-sided slab, situated between two fixed seating surfaces, with means to move it in or out of the flow stream in a direction perpendicular to the pipeline axis. . GROVE G4 GATE VALVE 36 VALVE TERMINOLOGY GAUGE, PRESSURE GLAND (or GLAND BUSHING) An instrument, usually with a threaded connection, for measuring and indicating the pressure in a piping system at the point at which it is connected. That part of a valve which retains or compresses the stem packing in a stuffing box (where used) or retains a stem O-ring, lip seal, or stem O-ring bushing. Sometimes manually adjustable. See Packing , Stuffing Box .“ “ “ “ STEM GLAND BUSHING STEM SEAL O-RINGS GLAND STEM PACKINGVALVE TERMINOLOGY 37 GLAND PLATE The plate in a valve which retains the gland, gland bushing, or stem seals, and sometimes guides the stem. GLOBE VALVE A valve whose closure element is a flat disc or conical plug sealing on a seat which is usually parallel to the flow axis. The tortuous flow path produces a relatively high pressure loss. STEM SEAL GLAND PLATE STEM SEAL STEM NAVCO GLOBE VALVE 38 VALVE TERMINOLOGY GREASE FITTING HWO - Handwheel Operated A fitting through which lubricant or sealant is injected. A valve on which the handwheel drives the stem directly to operate the valve. HARD FACING HEAD HEADER HEAT ANALYSIS A surface preparation, such as detonation gun or high velocity oxygen flow (HVOF), in which an alloy is deposited on a metal surface, usually by weld overlay, to increase abrasion and/or corrosion resistance The height of an open column of liquid above a given datum, expressed in linear units; i.e., feet of water, inches of mercury, etc. It is another way of expressing pressure. See Manifold . A chemical analysis, conducted by the foundry immediately prior to pouring, which measures the exact chemical composition of a particular batch of molten metal. Does not include analysis of physical properties. See Mill Test . . “ “ “ “VALVE TERMINOLOGY 39 HEAT TREATMENT HEAT TREATMENT CHARTS HOLIDAY HOT TAPPING HUBS Describes any process or procedure by which the internal structure of steel is altered by heating to produce desired physical characteristics. This is usually accomplished by furnace heating followed by controlled cooling Furnace charts providing a temperature vs. time record of the heating and cooling cycle, required by a specific heat treatment process for a particular furnace load of steel or steel parts. An imperfection or bare spot in a coating or plating. The process by which a pipeline, under pressure, is cut into to provide a side outlet. A flanged fitting is saddle-welded to the pipeline and a full port valve bolted to the flange. The hot tapping machine, bolted to the outboard valve flange, is operated through the open valve. After cutting out a circular piece from the pipe wall, the tapping machine is removed and the valve closed. The end connection tubes on a gate valve. . “ “ HUBS HUBS GROVE GATE VALVE 40 VALVE TERMINOLOGY HYDRAULIC HYDRAULIC MOTOR ACTUATOR ( or OPERATOR) HYDRAULIC SEATS HYDROSTATIC TEST (or SHELL TEST) ID - Inside Diameter IDS - Instrument Data Sheet INCREMENTAL SEAT TEST INERTIA INLET PORT Pertaining to, or using, water, oil, or other liquids A device by which rotation of an hydraulically powered motor is converted into mechanical motion. The movement of the seats in a valve that are controlled by using water, oil, or other liquids under pressure. A test in which a valve is completely filled with water and pressure tested. Used for conducting proof pressure testing. See Proof Pressure . The measurement of the inner diameter of a circular part. A table summarizing data such as service, valve size, supply pressure, etc., necessary in prescribed pressure steps. The leakage testing of valve seats in an assembled valve by increasing the applied pressure in prescribed pressure steps. The property of a body or mass which resists a change in velocity. That end of a valve which is connected to the upstream pressure zone of a fluid system. . “ “ An organization which sets minimum international standards for a wide variety of items manufactured and used in pipeline services. ISO - International Standards OrganizationVALVE TERMINOLOGY 41 INSIDE-OUT AIR SEAT TEST IN SITU MAINTENANCE INTERNAL PRESSURE RELIEF A pressure test that can be performed only on independent seating, trunnion mounted ball valves. By closing the valves and pressurizing the body cavity, all of the seals in an independent seating ball valve can then be pressure tested. To maintain or repair a product in its original place , such as a top entry ball valve or regulator. A self-relieving feature in non-independent seating valves that automatically relieves excessive internal body pressure caused by sudden changes in line pressures. By means of the piston effect principle the excessive body pressure will move the seat away from its seating surface and relieve it to the lower pressure side. “ “ “ “ BALL OUTER SEAT RING SEAT SEAL O-RING INNER SEAT RING INNER SEAT RING The inner part of a two-piece valve seat assembly.42 VALVE TERMINOLOGY KEY STOP LNG - Liquified Natural Gas LPG - Liquid Petroleum Gas LANTERN RING LIFTING LUGS A method of restricting the travel of a ball valve from fully open to fully closed. The stem key bears against the ends of an arc machined in the adapter plate. Natural gas in the liquid state. For the gas to remain liquified, the temperature must be maintained in the cryogenic region. The liquid occupies far less volume than an equivalent volume of gas and it can be readily transported by ship and stored ashore in insulated tanks to await re-gasification. Gases such as butane or propane in the liquid state. LPG, under relatively low pressure, remains a liquid at normal ambient temperature. See Chevron Packing . Lugs provided on larger ball, gate and check valves, for lifting and positioning valves. Also called lifting eyes. “ “ LIFTING LUG GROVE BALL VALVE VALVE TERMINOLOGY 43 LIMIT SWITCH LINE LIP SEAL LIQUID PENETRANT INSPECTION LOCK UP PRESSURE LOCKING DEVICE LUBE SEATS MAOP - Maximum Allowable Operating Pressure An electrical device providing a signal to a remote observation station indicating when the valve is in the fully open or fully closed position. Usually a component of a valve operator A pipe, tube or hose for conducting fluids. A circular seal ring of U shaped cross section encompassing an elastomeric O-ring which provides resiliency and ensures a seal at the inner and outer lips of the U . An NDE method of detecting the presence of surface cracks and surface imperfections in welds or castings through use of a special red dye. The differential pressure required to produce tight shutoff in a regulator. It is usually a few psi. A mechanism provided on valve operators to prevent unauthorized operation or tampering. Seats which are equipped with a lubricant injecting system. See Emergency Seat Seal . . Determined in accordance with piping codes, DOT regulations, etc. . “ “ “ “ “ “44 VALVE TERMINOLOGY MDS - Material Data Sheets MGO - Manual Gear Operator The material data sheets define the minimum requirements for the required materials, i.e., chemical requirements, manufacturing, qualification of supplier, mechanical testing and properties, non-destructive examination, repair, marking, and certification. A gear operator that is operated manually (with a handwheel). “ “ “ “, “ “ MMCF MO - Motor Operated An abbreviation for million cubic feet used to designate gas volume and gas flow rates in pipelines (MMCF per hour or day). See Power Operator EMO . MSS - Manufacturers Standardization Society of the Valve and Fitting Industry A technical association of valve, fitting and actuator manufacturers that writes standards and practices for the valve and fitting industry. Recommendations of this society are advisory only. MANUAL GEAR OPERATOR MOUNTED ON BALL VALVEVALVE TERMINOLOGY 45 MWP - Maximum Working Pressure (or CWP - Cold Working Pressure) Class MWP (CWP) MAGNETIC PARTICLE INSPECTION MALE THREAD MANIFOLD (or HEADER) The maximum working pressure (pounds per square inch) at which a valve can be operated. The maximum working pressure for various pressure classes, per Table 2.1 of API 6D, within temperature limits of -20°F and +100°F (-29°C and +38°C) are as follows: 150 275 300 720 400 960 600 1440 900 2160 1500 3600 2500 6000 An inspection procedure for detecting surface cracks in welded areas through the use of fine iron particles in an electrical field. The external thread on pipe, fittings or valves used in making a connection with mating female (internal) threaded parts. A common pipe or chamber having several lateral outlets. MANIFOLD46 VALVE TERMINOLOGY MASS SPECTROMETER MECHANICAL SEAL METAL-TO-METAL SEAL METER PROVER METER RUN An instrument used for sorting streams of electrified particles in accordance with their different masses by means of deflecting fields. The instrument can produce a photographic or graphic record of each compound and the percentage of the compound. Most commonly used in analyzing petroleum and steel products. In a valve, a shutoff that is accomplished by a mechanical means rather than with fluid or line pressure. The wedging action of a gate against the seats or the seat springs pushing the seat against the ball or gate are examples of mechanical seals in a valve. The seal produced by metal-to-metal contact between the sealing face of the seat ring and the closure elements, without benefit of a synthetic seal. A system used to check or prove a flow meter. A close fitting sphere is launched into a pipe of known inside diameter. The flow medium pushes the sphere through a measured length of pipe between two sphere detection devices. Knowing the transit time and the exact volume between the stations, a flow rate is calculated and compared with the meter reading. A section of pipeline in which a meter is installed to measure the volume of fluid passing through the line. “ “VALVE TERMINOLOGY 47 MILL CERTIFICATES MILL TEST MILL TEST REPORTS MODULUS (or COEFFICIENT) OF ELASTICITY MOLD MONITORING (or MONITOR SERVICE) NACE - National Association of Corrosion Engineers Certificates, provided by the steel mill, indicating the chemical analysis and physical properties of a specific batch of steel. Mill Certs are usually required only for pressure-containing parts. The customer's need for such Certs must be made known when the order is first placed, otherwise is it not possible to trace a valve part back to the mill. See Heat Analysis . All tests required by the material specification. Usually includes both the heat analysis (chemical) and the physical properties. Sometimes also impact tests. See Mill Certificates . The ratio between a force per unit area (stress) which acts to deform a body and the corresponding fractional deformation (strain) produced by the stress. A hollow cavity (frequently in packed sand) for giving a desired shape to a material in a molten or plastic state. Used in making metal castings. A field procedure whereby two valves - usually regulators - are installed in series and adjusted in such a manner that, should the primary regulator fail, the standby regulator will automatically take over at a slightly higher pressure setting The technical association publishes papers, articles and standards on all aspects of corrosion and has written the definitive standard for valve materials for sour gas service. “ “ “Mill “ “ “ “ “ .48 VALVE TERMINOLOGY NDE - Non-Destructive Examination NEMA - National Electrical Manufacturers Association NPT - National Pipe Tapered NEEDLE VALVE See Non-Destructive Tests . An association which has set up guidelines for the manufacture of electrical equipment. Generally applicable to specifications for switches, etc., for electric operators. A uniform standard governing the dimensions of tapered pipe threads. A type of small valve, used for flow metering, having a tapered needlepoint plug or closure element and a seat having a small orifice. “ “ NIPPLE WITH THREADED ENDS NIPPLE A short length of small size pipe, threaded on both ends. Used on end connections of screwed-end valves and in small size piping systems. NEEDLE VALVEVALVE TERMINOLOGY 49 NORMALLY CLOSED SOLENOID VALVE An electrically operated valve whose inlet orifice is closed when the solenoid coil is not energized. Energize to open. See Solenoid Valve .“ “ WEDGE GATE VALVE WITH NON-RISING STEM NITROGEN/HELIUM TEST A pressure test conducted using nitrogen or helium (inert gases) instead of air, water, or other gases to prevent any danger of fires or explosions. Generally specified by the purchaser when buying a valve or regulator product. NON-DESTRUCTIVE TESTS NON-RISING STEM Those inspection tests which are not destructive to the valve structure or function. See “Radiographic Inspection“, “Liquid Penetrant Inspection“, “Magnetic Particle Inspection“, and “Ultrasonic Inspection“. A gate valve having its stem threaded into the gate. As the stem turns, the gate moves but the stem does not rise. Stem threads are exposed to line fluids.50 VALVE TERMINOLOGY NORMALLY OPEN SOLENOID VALVE OCMA - Oil Companies Materials Association OD - Outer Diameter OLDHAM COUPLING An electrically operated valve whose inlet orifice is open when the solenoid coil is not energized. Energize to close. See Solenoid Valve . An association of British oil companies which has written a standard for fire safe testing of soft seated valves. See Fire Safe . The measurement of the outermost diameter of a circular part. A double slider connection used to connect shafts “ “ “ “ “ “ O-RING An elastomeric or synthetic seal ring of circular cross-section. O-RINGS OLDHAM COUPLINGVALVE TERMINOLOGY 51 OPERATING TIME OPERATOR OS&Y - Outside Screw and Yoke The time required for a power operator to stroke the valve from a full open to full closed position or vice versa. A device which converts manual, hydraulic, pneumatic or electrical energy into mechanical motion to open and close a valve. See “Power Operator“, “EMO“, “GO“, “HWO“, “MGO“, "MO". A valve in which the fluid does not come in contact with the stem threads. The stem sealing element is between the valve body and the stem threads. OUTER SEAT RING The outer metal piece of a two-piece seat ring unit. See Inner Seat Ring .“ “ WEDGE GATE VALVE WITH OS&Y52 VALVE TERMINOLOGY PSI (psi) PACKING An abbreviation for orce per unit area exerted against a resisting body. The deformable sealing material inserted into a valve stem stuffing box, which, when compressed by a gland, provides a tight seal about the stem. See Gland Stuffing Box . “pounds per square inch“. The f “ “, “ “ PACKING GLAND PATTERN PEAK SHAVING See "Gland". A duplicate or copy, usually wooden, of a part to be cast. Used to form the mold into which molten metal is poured. When daily usage of natural gas is charted on graphs, it will show high peaks (of usage) during the winter months. These peaks can be shaved (averaged out) when the daily consumption is augmented with standby supplies of synthetic natural gas, propane, or methane “ “ . GLAND PACKINGVALVE TERMINOLOGY 53 PHENOLIC COATING PIG A thermo-setting resin applied to valve interiors and/ or exteriors to inhibit corrosion. A plastic material. A device, closely conforming to the pipe bore, which is forced through a pipeline to clean the pipe of all foreign material and debris. The valves in a pipeline that will be pigged must be through-conduit, full port; otherwise the pig will not pass through them. PILOT A spring-loaded pressure regulator used to control the pressure and flow of other larger pressure regulators or instruments. 24” PIG WITH URETHANE BLADES54 VALVE TERMINOLOGY PILOT-OPERATED REGULATOR A regulator which is controlled by a second small volume, high accuracy regulator or pilot. This arrangement has the advantages of improving performance by minimizing the effects of unbalanced pressure and droop. The number of possible applications are also increased since a wide range of pilot configurations are feasible. PILOT REGULATORVALVE TERMINOLOGY 55 PINION SHAFT EXTENSION On a buried valve, the gear operator pinion shaft must be extended above grade to permit the valve to be operated. PINION SHAFT PINION SHAFT The external input shaft of certain gear operators which drives the internal reduction gearing. The pinion shaft can accept a handwheel or power operator.56 VALVE TERMINOLOGY PLUG PISTON EFFECT The sealing principle involved in utilizing line pressure to effect a seal across the floating seats of some valves. PITCH AND LEAD Pertaining to screw threads, the pitch refers to the measurement between adjacent threads. The lead refers to the distance the screw advances in one complete revolution. Worm gears of gear operators are also identified by pitch and lead. Speed of operation and torque required are related to pitch and lead. PLASTICS A broad classification covering a variety of nonmetallic, synthetic or organic materials capable of being molded or formed into desired shapes. Also used as a protective coating for valves. PLUG The rotating closure element of a plug valve. Also a threaded fitting used to close off and seal an opening into a pressure-containing chamber, e.g., pipe plug. PLUG VALVE A quarter-turn valve whose closure element is usually a tapered plug having a rectangular port.VALVE TERMINOLOGY 57 PNEUMATIC Pertaining to, or using, air or gas. POLY PAK STEM SEAL (A Parker Seal Company Product) An O-ring energized lip seal which replaces the O-ring stem seal in certain gate valves. Also used for stem seals in some ball valves. See “Lip Seal“. POSITION INDICATOR Any external device which visually indicates the open and closed position of a valve. See “Stem Indicators“. POWER OPERATOR Powered valve operators are of the following general types: Electric Motor, Pneumatic or Hydraulic Motor, Pneumatic or Hydraulic Cylinder. Operators can either be adapted directly to the valve stem or side mounted on existing gear or scotch yoke operators. PRESSURE See “PSI“. PRESSURE DIFFERENTIAL See “Differential Pressure“. PRESSURE DROP Decrease in pressure along the direction of flow in a piping system caused by fluid friction, and change-of-direction fittings. Pressure drop is related to velocity, specific gravity, viscosity and the size and roughness of the pipe interior. See “Differential Pressure“. PRESSURE REDUCING REGULATOR Regulator designed to control downstream pressure. See “Regulator“. PORT See “Bore“. restrictions,58 VALVE TERMINOLOGY PRESSURE SWITCH A switch (usually electric) activated by a rise or drop in pressure. A transducer. PRESSURE TEST A test using specified pressures of liquid or gases, which can be used to check the sealing, integrity, design standards, etc., of a particular product. PRODUCT ANALYSIS A verification conducted by the valve manufacturer to assure that the chemical composition of received material coincides with the heat analysis and with requirements of the applicable specification. PRODUCT STANDARDIZATION The process by which purchasers ensure consistency of a product's quality by the approval of the vendors' standardized documentation. This is normally used as the basis for blanket purchase agreements. PROOF PRESSURE A hydrostatic test pressure, usually 1 1/2 times the rated working pressure, applied to an assembled valve to verify the structural integrity of the pressurecontaining parts. Synonymous with hydrostatic shell test. (Table 5.1, API 6D). PROTECTIVE SLEEVES A circular “pipe-like“ sleeve inserted in place of the ball and seats of a top entry ball valve. This protective sleeve remains in place inside the valve during valve installation and ultimate pigging of a pipeline to clear debris from the line before placing the pipeline into service. Once the pipeline has been purged of all debris, the protective sleeve is removed entirely from the ball valve cavity, and operating trim (i.e., ball and seats) is then installed for normal service conditions.VALVE TERMINOLOGY 59 PULSATION Rhythmical throbbing or vibrating. In pipelines, a flow or pressure oscillation which is identically repeated in every fixed time interval. Pulsation is an inherent characteristic of reciprocating gas compressors and reciprocating liquid pumps. Pressure and flow pulsations interact with piping systems to cause vibration, metering errors and potential equipment damage. PUMP A rotary or reciprocating device using mechanical energy to propel liquids through pipelines or to draw liquids from tanks or sumps by suction. PUMP CONTROL VALVE A ball valve that is not meant for on-off service, but whose specific function is to control flow and prevent cavitations in pumps on liquid pipelines. PUPS See “Transition Piece“. QUALIFICATION TEST An investigation, independent of a purchasing function, that is performed on a product to determine whether or not the product conforms to all of the requirements of a particular specification. This is generally done by a third independent party to qualify a product for a specific application. QUALITY ASSURANCE Planned regular and/or preventive actions which are used to ensure that materials, products, or services will meet specified requirements.60 VALVE TERMINOLOGY RF - Raised Face The raised area of a flange face which affords a seal with a mating flange face by means of a flat gasket of the same diameter as the raised face. RPM - Revolutions Per Minute Rotational speed, turns per minute. For example, the RPM delivered by a power operator to the pinion shaft of a gear operator. RTJ or R.T.J. - Ring Type Joint A flange connection using a specially shaped soft metal ring as a gasket. Generally used on high pressure valves and not widely used in the pipeline industry. RADIOGRAPHIC INSPECTION An X-ray NDE procedure for locating flaws in welds, casting, and fabricated parts. RAISED FACE OVAL RING OCTAGONAL RINGVALVE TERMINOLOGY 61 RATCHET DRIVE A shaft or valve that is operated by means of a ratchet mechanism. The ratchet delivers an intermittent stepped rotation through a gear in one direction only. REDUCED PORT (or REDUCED BORE) See “Venturi“ Valve. REGULAR PORT VALVE A term usually applied to plug valves. The “regular“ port of such a valve is customarily about 40% of the line pipe area. Hence, it corresponds to a VenturI or reduced bore valve of the same nominal pipe size. Venturi ball valves are often a logical alternative to plug valves with advantages in price torque and low maintenance. REGULATOR A throttling valve which exercises automatic control over some variable (usually pressure). Not an on-off valve. GROVE MITY-MITE PRESSURE-REDUCING REGULATOR IN OUT62 VALVE TERMINOLOGY RELIEF VALVE A quick acting, spring-loaded valve that opens (relieves) when the pressure exceeds the spring setting. Often installed on the body cavity of ball and gate valves to relieve thermal overpressure in liquid services. See “B.R.V“ and Section 2. REMOTE CONTROL The operation of a valve or other flow control device from a point at a distance from the device being controlled. Can be accomplished by electrical, pneumatic or hydraulic means. RESILIENT SEAT A valve seat containing a soft seal, such as an O-ring, to assure tight shutoff. RISING STEM A valve stem which rises as the valve is opened. RISING STEM GATE VALVEVALVE TERMINOLOGY 63 RISING STEM BALL VALVE A single-seated ball valve that is designed to seal by using the valve's stem to mechanically wedge the valve's ball into a stationary seat, effecting a bubbletight seal. The valve's stem operates through a guide sleeve assembly that guides the stem through a quarter turn of rotation as the stem is raised or lowered by a handwheel (or actuator). The mechanical action of the stem moves the ball away from the seat prior to the 90° rotation of the ball. The design provides lower operating torques and longer seat life while assuring bubble-tight shutoff. ORBIT RISING STEM BALL VALVE64 VALVE TERMINOLOGY ROAD BOX A concrete or metal box with a removable cover, enclosing and providing access to valves installed in buried lines alongside roads or streets. The valves are operated by removing the box cover and inserting a long-handled “T“ wrench which engages a 2” square nut attached to the valve stem or to the pinion shaft of geared valves. ROCKWELL HARDNESS NO. A numerical expression of the hardness of a metal as determined with a Rockwell Hardness Tester. There are several hardness scales. The most commonly used are the Rockwell B scale for soft metals and the Rockwell C scale for hard materials. RUPTURE DISC (or BLOW-OUT DISC) An emergency over pressure relief device, a relatively thin diaphragm designed to burst at a specified pressure. It cannot be reset, but must be replaced after rupture event. SNG - Synthetic Natural Gas A substitute natural gas made from the byproducts of chemical plants and refineries. See “Coal Gasification“. SPDT - Single-Pole, Double-Throw See “SPST“. SPST - Single-Pole, Double-Throw Refers to the function of an electrical switch often used in the control system of electric valve operators. SSIV - Subsea Isolation Valve A valve used underwater, generally in a manifold that will close and isolate a particular pipeline or process in an emergency. SY - Scotch Yoke See “Scotch Yoke Operator“.THE PRESSURE AT WHICH VALVE RELIEVES IS SET BY ADJUSTING SPRING FORCE SPRING-LOADED SAFETY VALVE VALVE TERMINOLOGY 65 SAFETY VALVE A quick opening, pop action valve used for fast relief of excessive pressure. SCHEDULE A system for indicating the wall thickness of pipe. The higher the schedule number, the thicker the wall for a certain pipe size. SCOTCH YOKE OPERATOR A quarter-turn operator for use on quarter-turn values using a scotch yoke mechanism rather than gears. The scotch yoke has a torque output at the beginning and ending of its stroke that is generally twice the magnitude of the torque output in the center of its stroke. GUIDE BAR YOKE VALVE STEM SCOTCH YOKE OPERATOR66 VALVE TERMINOLOGY SCREWED ENDS Internally threaded end connections supplied on some valves. Usually tapered pipe threads. See “NPT“. SEAL, DYNAMIC A sealing element used between parts that have relative motion, i.e.. stem seals, seat seal O-rings, etc. SEAL, STATIC A sealing element used as a gasket between two non-moving parts, i.e., valve bonnet O-rings, ball valve body O-rings, flange gaskets, etc. SEAT That part of a valve against which the closure element (gate, ball) effects a tight shutoff. In many ball valves and gate valves, it is a floating member containing a soft seating element (usually SEAT GATE SLAB GATE POSITIONED BETWEEN SEAT RINGSVALVE TERMINOLOGY 67 SELF RELIEVING The process whereby excessive internal body pressure, in some valves, is automatically relieved into either the upstream or downstream line by forcing the seats away from the closure elements. SEPARATOR A special tank used to separate gas from oil in some crude oil gathering systems. SHORT GATE A gate valve whose seat rings contact the gate only in the closed position. Such valves are not through conduit, as the gate is completely withdrawn from the flow area in the open position. SHORT PATTERN VALVE A valve whose face-to-face dimension is less than the API 6D standard. SHUTOFF VALVE A valve designed only for on/off service. Not a throttling valve. Sometimes referred to as a “block valve“. SLAB GATE A gate having flat, finely finished, parallel faces as opposed to a wedge gate. Such a closure element slides across the seats and does not depend on stem force to achieve tight shutoff. GATE BORE SLAB GATE GATE BORE68 VALVE TERMINOLOGY SLAM RETARDER A device to prevent the clapper of a check valve from slamming as it closes upon flow reversal. Hydraulic damping cylinders, rotary vanes and torsional springs are all used for this purpose. SLURRY SERVICE An application involving a flow medium consisting of small solid particles suspended in a liquid. Coal slurry, consisting of about equal parts of coal and water, is transported by pipeline from coal mines to Dower plants where the coal is de-watered and burned. A specially modified GROVE B5 ball valve is offered for this service. SOCKET END An end connection in which a pipe or tube is inserted into a counterbored hole and then brazed or filletwelded. CLAPPER SHAFT TORSIONAL SPRING SLAM RETARDER TEE WITH SOCKET ENDSVALVE TERMINOLOGY 69 SOLENOID VALVE A small electrically operated valve used in the control piping of powered hydraulic or pneumatic cylinder operators. SOUR GAS Natural gas containing significant amounts of hydrogen sulfide (H2S). Requires special trim. SPECIFIC GRAVITY The ratio of the weight of a given volume of fluid to the weight of an equal volume of water (if the fluid is a liquid) or to the weight of an equal volume of air (if the fluid is a gas). SPHERE-LOK (a GROVE trade name) A ball valve having a blind pocket in the ball rather than a through hole. The valve will catch and hold a metal sphere and then launch it down the pipe. Used in meter prover systems to accurately measure flow rates and calibrate flow meters. See “Two-Way Sphere-Lok“, “Meter Prover“. MAGNETIC COIL ARMATURE NORMALLY CLOSED - ENERGIZED TO OPEN70 VALVE TERMINOLOGY SPOOL PIECE See Adapter Spool . SPUR GEAR The simplest of gears. In a gear set, the pinion and ring gear are aligned on parallel shafts. STEM A rod or shaft transmitting motion from an operator to the closure element of a valve. STEM INDICATOR (or VPI - Visible Position Indicator) A position-indicating rod supplied with gate valves. It extends from the top of the valve stem and serves to indicate the relative position of the gate. “ “ STEM NUT A one or two-piece nut which engages the stem threads of a valve and transmits torque from an operator to the valve stem. STEM INDICATOR (VPI) VALVE STEMVALVE TERMINOLOGY 71 STOP COLLAR The collar on a ball valve which restricts the ball to 90° of rotation from the fully closed position. See “Key Stop“. STOPPLE (or STOP OFF) A procedure used in the repair of a pipeline to isolate a section of line in the absence of a shutoff valve. After welding a flanged saddle to the pipe, the line is “hot tapped“and an expanding resilient plug is inserted into the pipe bore. When the repair is completed, the plug is withdrawn and a valve, installed on the saddle flange, is closed. STRAIN GAUGE An instrument used to measure small or minute distortions caused by stress forces in mechanical components. STREET ELL A 90° pipe fitting with male and female threaded ends. STRESS An engineering parameter used in the design of valves. The value of unit force (psi) produced within a material as the result of an applied force or load. Developed stress must be held well below the yield strength of the material. STOP COLLAR 90° STREET ELL72 VALVE TERMINOLOGY STUD A bolt, threaded on both ends, often used in bolting together two members, one of which has blind tapped bolt holes. Comprises the bolting sets of GROVE G5D and G9 gate valves. STUFFING BOX The annular chamber provided around a valve stem in a sealing system into which deformable packing is introduced. See “Packing“, “Gland“. SUBMERSIBLE SERVICE Underwater or subsea installation. Valves require special treatment to protect against corrosion and external seawater pressure. SURGE To rise suddenly to an excessive or abnormal value; a transient sudden rise of pressure in a pipeline. Pipeline surges can be positive or negative and are caused most frequently by the sudden closure of a block valve or emergency shutdown of a pump. Surge pressure in excess of the rated capacity of a pipeline can cause ruptures of the piping system. See Section 2. STUD-BOLTS JOINING TWO FLANGES BLIND TAPPED HOLEVALVE TERMINOLOGY 73 SURGE RELIEVER A valve designed to relieve pressure surges in liquid pipelines, thus preventing line rupture due to transient pressures exceeding design limits of the pipe. A special flexible tube valve can function as a fast-acting surge reliever. See Section 2. SWAGE A tool for bending or forming cold metal to a required shape. SWEET GAS Natural gas having no significant hydrogen sulfide content. SWING CHECK VALVE A check valve in which the closure element is a hinged clapper which swings or rotates about a supporting shaft. See “Clapper“, “Check Valve“. SYSTEM ENGINEERING That engineering approach which deals with the design and integration of multiple components and controls into an assembled piping complex to accomplish a specified function or functions. The skid-mounted Arcron Surge Reliever is an example of system engineering. See Section 2. TEE A pipe or tubing fitting with a side outlet at right angles. TEE74 VALVE TERMINOLOGY TENSILE STRENGTH The highest tensile stress that a material can withstand before failure or rupture occurs with force being applied in a direction tending to elongate the material. TENSILE TEST A test performed on specially machined specimens taken from material in its delivered condition, to determine physical properties, i.e., yield strength, ultimate strength and percent elongation. TENSION TEST
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