CSA 6 18-2002 Service Regulators for Natural Gas (Third Edition).pdf

1、CSA 6.18-02(reaffirmed 2013)Service Regulators for Natural GasLegal Notice for StandardsCanadian Standards Association (operating as “CSA Group”) develops standards through a consensus standards development process approved by the Standards Council of Canada. This process brings together volunteers

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15、RTHESOLEPURPOSEOFREVIEWINGITsSEARCHANDBROWSETHISDOCUMENTANDsPRINTTHISDOCUMENTIFITISIN0$(b) a new comprehensive clause on definitions has been added;(c) this edition requires that all regulators be capable of operation over a temperature range of 40F(40C) to 150F (65.6C); and(d) a new appendix (Appen

16、dix B) describing a variable temperature performance test has been includedto determine how the regulator components will perform when subjected to variable temperaturesobserved under field conditions.This Standard was prepared by the CSA 6.18 Technical Committee on Service Regulators for NaturalGas

17、, under the jurisdiction of the Strategic Steering Committee for the Gas Industry, and has beenformally approved by the Technical Committee and the Interprovincial Gas Advisory Council.August 2002Notes:(1) Use of the singular does not exclude the plural (and vice versa) when the sense allows.(2) Alt

18、hough the intended primary application of this Standard is stated in its Scope, it is important to note that itremains the responsibility of the users of the Standard to judge its suitability for their particular purpose.(3) This publication was developed by consensus, which is defined by CSA Policy

19、 governing standardization Codeof good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority,but not necessarily unanimity”. It is consistent with this definition that a member may be included in the TechnicalCommittee list and yet not be in full

20、agreement with all clauses of this publication.(4) CSA Standards are subject to periodic review, and suggestions for their improvement will be referred to theappropriate committee.(5) All enquiries regarding this Standard, including requests for interpretation, should be addressed to CanadianStandar

21、ds Association, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6. Requests for interpretation should(a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;(b) provide an explanation of circumstances surrounding the ac

22、tual field condition; and(c) be phrased where possible to permit a specific “yes” or “no” answer.Committee interpretations are processed in accordance with the CSA Directives and guidelines governingstandardization and are published in CSAs periodical Info Update. For subscription details, write to

23、CSA SalesPromotion, Info Update, at the address given above. Canadian Standards Association Service Regulators for Natural Gas1August 2002CSA 6.18-02Service Regulators for Natural Gas1. Scope1.1 These provisions apply to the construction, materials, performance, and testing of NPS 1-1/4 in andsmalle

24、r self-acting service-type regulators with internal relief valves or overpressure cut-off (OPCO)*devices, or both, utilized to control the pressure of gas delivered to a customers piping at a deliverypressure of 5 to 9 in water column (1.24 to 2.24 kPa), for installations designed for capacities up

25、to250 SCFH (7.1 m /h).3*Overpressure cut-off (OPCO) devices are also referred to as overpressure shut-off (OPSO) devices.1.2The yard-pound units provided are the standard. The SI (metric) equivalents in parentheses may beapproximate values and are provided for information only, or for markings where

26、 both units ofmeasurement are required.2. Definitions, Symbols, and Abbreviations2.1 DefinitionsThe following definitions apply in this Standard:Boost an increase in the outlet pressure from set point with respect to increasing flow rate.Casting the diaphragm casing and the regulator valve body and

27、any other pressure-containingcomponents, excluding the diaphragm and gaskets.Diaphragm a flexible element used to sense the outlet pressure.Diaphragm casing the components of the diaphragm casing assembly that constitute the pressureshell, excluding the diaphragm and gaskets.Diaphragm casing assembl

28、y the housing for the diaphragm, which usually consists of anatmospheric or ambient casing and a gas or fuel casing. The gas or fuel casing and the diaphragm formthe gas or fuel chamber. The atmospheric or ambient casing and the diaphragm form the atmosphericor ambient chamber. The diaphragm seals a

29、nd separates the gas or fuel chamber from the atmosphericor ambient chamber. The atmospheric or ambient chamber houses the loading spring and vents intothe atmosphere.Droop a drop in outlet pressure from set point with respect to increasing flow rate.Flow capacity the maximum gas flow rate provided

30、by the regulator with outlet pressure stayingabove the droop and below the boost limits as flow is increased from set flow.Hysteresis a deviation in the regulator performance based on internal friction, the diaphragmmaterial, and flow.CSA 6.18-02 Canadian Standards Association2August 2002Inlet the c

31、onnection and piping on the supply side (upstream) of the regulator body.Inlet pressure the gas supply pressure upstream of the regulator.Internal relief valve (IRV) a relief valve that relieves excessive outlet pressure through thediaphragm and vent assembly.Note: The internal relief set point is a

32、 function of the regulators set point and the maximum allowablebuildup of downstream pressure.Loading spring a spring placed on the diaphragm or diaphragm plate and contained in theatmospheric casing that opposes the gas pressure exerted against the opposite side of the diaphragm. Note: The outlet p

33、ressure of the regulator is set by compression of this spring.Lock-up the state of the regulator when inlet pressure is applied and no gas is flowing.Lock-up pressure the outlet pressure above which there is no flow through the regulator.Low pressure shut-off or cut-off a device designed to stop the

34、 flow of gas when the outletpressure drops below a predetermined pressure.Orifice the primary flow restrictor that is used to control the flow of gas.Note: The position of the valve disc with respect to the orifice seating surface determines the amount of gas flowingthrough the regulator.Orifice gas

35、ket a soft material that, when used, creates a pressure-tight seal between the orifice andvalve body.Outlet the connection and piping on the discharge side (downstream) of the regulator body.Outlet pressure the gas discharge pressure downstream of the regulator.Overpressure shut-off or cut-off a dev

36、ice designed to stop the flow of gas when the outletpressure rises above a predetermined pressure.Piezometer tubes a standardized piping configuration used for measuring inlet and outlet pressure. It consists of a pipe nipple of predetermined length with holes drilled through the nipple at apredeter

37、mined location, a hollow ring covering and sealing the holes, and a pressure connection fromwhich an average pressure is measured.Pressure Absolute gauge pressure plus the barometric or atmospheric pressure.Atmospheric the pressure due to the weight of the atmosphere on the earths surface.Gauge pres

38、sure measured relative to the atmospheric pressure.Regulator head assembly the actuator portion of the regulator typically consisting of everythingbut the body and orifice. The regulator head assembly normally includes the diaphragm casings,diaphragm loading spring, spring adjustment mechanism, inte

39、rnal relief valve linkage, and valve seat.Regulator valve body the part of the regulator that consists of the inlet and outlet pipingconnections and the orifice. Canadian Standards Association Service Regulators for Natural Gas3August 2002Reseating pressure the pressure at which flow from the intern

40、al relief valve stops when it is in anactive or flowing condition.Seal cap the cap serving as a weather seal and external closure for the loading spring and springadjustment mechanism.Set flow the flow rate used for the initial setting of the regulator at a specified inlet pressure andoutlet set pre

41、ssure.Set point see Set pressure.Set pressure the initial setting of the regulator outlet pressure at a specified set flow and inletpressure.Setting pressure see Set pressure.Spring adjustment mechanism a threaded part by which the loading spring is adjusted to set theoutlet pressure.Standard cubic

42、feet per hour (SCFH) a standardized method of defining gas flow rate. For thepurpose of this Standard, a standard cubic foot is defined as a volume of 1 ft (0.0283 m ) of gas at a33temperature of 60F (15.6C) and at an absolute pressure of 14.73 psia (101.56 kPa).Start-to-relieve pressure the pressur

43、e at which the first discernable continuous flow is detectedfrom the internal relief valve. Static or control line an external line connected between the regulator fuel casting and thedownstream piping to provide a pressure or control feedback signal.Valve that part of the regulator consisting of a

44、valve orifice and valve disc that is used to control gasflow through the regulator.Valve body the part of the regulator that consists of inlet and outlet piping connections and thathouses the orifice.Valve disc a resilient disc or similar device that is positioned with respect to the regulator valve

45、 orificeto control and shut off the flow of gas.Valve linkage a lever or other mechanism connecting the diaphragm to the valve disc.Valve seat see Valve disc.Vent the opening to the atmospheric side of the diaphragm casing through which atmosphericpressure is registered against the diaphragm. This i

46、s also the point for connection of a vent pipe or capand could also be the opening for discharge of gas from the internal relief valve.Vent cap a cap that is inserted into the vent of the regulator to keep insects or water from enteringthe regulators atmospheric or ambient casing.Water column (wc) a

47、 pressure measurement unit derived from a water manometer. It equals thepressure required to support the weight of 1 inch of water.CSA 6.18-02 Canadian Standards Association4August 20022.2 SI (Metric) SymbolsThe following SI symbols apply in this Standard:C = degrees Celsiuscm /h = cubic centimetres

48、 per hour3cm = centimetrecm = cubic centimetre3g = gramh = hourHz = hertzkm/h = kilometres per hourkPa = kilopascalL/min = litres per minutem = metrem /h = cubic metres per hour3min = minutemL = millilitremm = millimetreN = newtonN m = newton metrerad = radianV = volt2.3 AbbreviationsThe following abbreviations apply in this Standard:F degrees Fahrenheit fl oz fluid ounceft footft-lb foot-poundgpm gallons per minuteID inside diameterin wc inches water columnlb poundmph miles per hourNPS nominal pipe sizepsia pounds per square inch, absolutepsig pounds per square inch, gaugeS