压力表安装操作和维护(英文：PRESSURE GAUGE INSTALLATION OPERA

英文的压力表安装,操作和维护方面的比较专业的描述

PRESSURE GAUGEINSTALLATION, OPERATION AND

MAINTENANCE

英文的压力表安装,操作和维护方面的比较专业的描述

1.0 SELECTION & APPLICATION

Users should become familiar with ASMEB40.100 (Gauges–Pressure Indicating Dial Type – Elastic Element) beforespecifying pressure measuring gauges. That document –containing valuable information regarding gauge construction,accuracy, safety,selection and testing – may be ordered from:

ASME InternationalThree Park Avenue

New York, N.Y. 10016-5990800-843-2763 (US/Canada)001-800-843-2763 (Mexico)

973-882-1170 outside North Americaemail: infocentral@http://doc.guandang.netWARNING:To prevent misapplication, pressure gauges

should be selected considering media and ambient operatingconditions. Improper application can be detrimental to thegauge, causing failure and possible personal injury, propertydamage or death. The information contained in this manual isoffered as a guide in making the proper selection of a pressuregauge. Additional information is available from Ashcroft Inc.The following is a highlight of some of the more important con-siderations:

1.1 Range– The range of the instrument should be approxi-mately twice the maximum operating pressure. Too low arange may result in (a) low fatigue life of the elastic elementdue to high operating stress and (b) susceptibility to over-pressure set due to pressure transients that exceed the nor-mal operating pressure. Too high a range may yield insuffi-cient resolution for the application.

1.2 Temperature– Refer to Section 2 of this manualforimportant information concerning temperature related limita-tions of pressure gauges, both dry and liquid filled.

1.3 Media– The material of the process sensing element mustbe compatible with the process media. Use of a diaphragm sealwith the gauge is recommended for process media that (a) iscorrosive to the process sensing element; (b) contain heavyparticulates (slurries) or (c) are very viscous including thosethat harden at room temperature.

1.4 Oxidizing media– Gauges for direct use on oxidizingmedia should be specially cleaned. Gauges for oxygen ser-vice should be ordered to variation X6B and will carry theASME required dial marking “USE NO OIL” in red letters.Gauges for direct use on other oxidizing media may beordered to variation X6W. They will be cleaned but carry nodial marking. PLUS! Performance gauges or Halocarbonfilled gauge or diaphragm fill is required for use with oxidiz-ing media; order variation XCF.

1.5 Pulsation/Vibration– Pressure pulsation can be damp-ened by several mechanisms; the patented PLUS! Perfor-mancegauge will handle the vast majority of applications.One exception to this is high frequency pulsation which isdifficult to detect. The only indication may be an upscale zeroshift due to movement wear. These applications should beaddressed with a liquid filled gauge, or in extreme cases, aremotely mounted liquid filled gauge connected with a lengthof capillary line. The small diameter of the capillary providesexcellent dampening, but can be plugged. The Ashcroft 1106pulsation dampener and 1112 snubber are auxiliary deviceswhich dampen pulsation with less tendency to plug.

1.6 Gauge fills. – Once it has been determined that a liquidfilled gauge is in order, the next step is selecting the type of fill.

Glycerinsatisfies most applications. While being the leastexpensive fill, its usable temperature range is 20/180°F.Siliconefilled gauges have a broader service range:

–40/250°F. Oxidizing media require the use of Halocarbon,with a service range of –40/250°F. Pointer motion will beslowed at the low end of the low end of these temperatureranges.

1.7 Mounting– Users should predetermine how the gaugewill be mounted in service: stem (pipe), wall (surface) or panel(flush). Ashcroft wall or panel mounting kits should be orderedthe gauge. See Section 3.

2.0 TEMPERATURE

2.1 Ambient Temperature– To ensure long life and accura-cy, pressure gauges should preferably be used at an ambi-ent temperature between –20 and +150°F (–30 to +65°C). At very low temperatures, standard gauges may exhibit slowpointer response. Above 150°F, the accuracy will be affectedby approximately 1.5% per 100°F. Other than discoloration ofthe dial and hardening of the gasketing and degradation ofaccuracy, non-liquid filled Type 1279 (phenolic case) and1379 (aluminum case) Duragauge® gauge,with standard

glass windows, can withstand continuous operating tempera-tures up to 250°F. Unigauge models 21 2 and 31 2 1009 and1008S liquid filled gauges can withstand 200°F but glycerinfill and the acrylic window of Duragauge®gauges will tend toyellow. Silicone fill will have much less tendency to yellow.Low pressure, liquid filled Types 1008 and 1009 gauges mayhave some downscale errors caused by liquid fill expansion.This can be alleviated by venting the gauge at the top plug(pullout the blue plug insert). To do this the gauge must beinstalled in the vertical position.

Although the gauge may be destroyed and calibration lost,gauges can withstand short times at the following tempera-tures: gauges with all welded pressure boundary joints, 750°F(400°C); gauges with silver brazed joints, 450°F (232°C) andgauges with soft soldered joints, 250°F (121°C). For expectedlong term service below –20°F (–30°C) Duragauge®and 41 2 1009 gauges should be hermetically sealed and speciallylubricated; add “H” to the product code for hermetic sealing.Add variation XVY for special lubricant. Standard Duralife®gauges may be used to –50°F (–45°C) without modification.2.2 Accuracy– Heat and cold affect accuracy of indication.A general rule of thumb for dry gaugesis 0.5% of full scalechange for …… 此处隐藏：26527字，全部文档内容请下载后查看。喜欢就下载吧 ……