Introduction

JJG52-2013Elastic element type general pressure gaugepressure vacuum gaugeThe verification regulations for vacuum gauges include general pressure gaugesPressure vacuum gaugeVacuum gauge and capsule pressure gauge.This article only discusses general pressure gaugesPressure reallyComparison of new and old calibration criteria for empty and vacuum gauges,Better based on the new versionThe verification regulations guide the verification work.

1Main technical changes in the new version of the verification regulations

JJG52-2013Elastic element type general pressure gaugepressure vacuum gaugeThe verification regulations for vacuum gauges areJJG52-1999

Spring tube general pressureForce gaugePressure Vacuum Gauge and Vacuum GaugeJJG573-2003Membrane Box PressureOn the basis of merging the two regulations,Retaining effective content prerequisitesMake revisions below.JJG52-2013andJJG52-1999TheJJG573-2003phaseCompared to,Apart from editorial modifications,The main technological changes are as follows:

（1）pressJJF 1002 - 2010The requirement has been added to the introduction sectionRong;

• The regulations coverJJG52-1999TheJJG573-2003The content of two regulations applies to general pressure gauges with elastic elements and pressure gaugesCalibration of vacuum gauges and vacuum gauges;

（3）Deleted the content of the upper limit of the measurement range in the scope;

（4）Improved the content of the overview section;

（5）Refined the verification conditions;

（6）Ordered the verification items and methods;

（7）Added 'Verification Certificate'/Notice of Verification Results Internal Page LetterAppendix to "Information and Format";

（8）The list of allowable error calculation values for pressure gauges has been deleted.

2Comparison of old and new calibration regulations

2.1 increase“Reference document”terms.

JJG52-2013Reference documentJJF 1008 - 2008Pressure Measurement TerminologyTerms and Definitions "andGB/T1226-2010General pressure gauge.

2.2 increase“Terminology and measurement units”terms.

（1）Provide "elastic element pressure gauge" and "set point deviation" The definitions of "switching value" and "switching difference".

Elastic element pressure gauge: an instrument that measures pressure using an elastic sensitive element as the sensing element.

Setpoint deviation: When the output variable is output according to the specified requirements, setThe difference between the measured value and the actual value.

Switching value: Up stroke of positional control instrument（Or travel downwards）In the middle, loseThe input quantity measured when transitioning from one state to another.

Switching difference: the difference between the upper and lower stroke switching values at the same set point.

（2）The legal unit of measurement isPa, or its decimal multiple unit:KPaTheMPaWait.

2.3 “Overview”Changes in Content.

Refined the working principle of the pressure gauge and pointed out the production of elastic sensitive componentsAfter elastic deformation, the magnitude of its deformation is determined by the applied pressureLinear relationship.

According to the different types of elastic sensitive components, they can be divided into: spring tube type, membrane box type, diaphragm type, and corrugated tube type.

2.4“Measurement performance requirements”The changes in the content.

（1）In the accuracy level and maximum allowable error table, the digits are uniformly expressed.

The 'zero position error' is defined in the original 'General Technical Requirements'Adjust to this section.

（2）Under atmospheric conditions "replaces the expression" in the absence of pressure or vacuum "in the original regulations.

（3）Add the clause 'Zero position error of membrane box pressure gauge'.

（4）Add content to "pointer deflection stability": double needle doubleThe two pointers of a tube or double needle single tube pressure gauge should not affect each other when deflected.

The new regulations provide for the deviation of the set point of the electric contact pressure gaugeThe values of 'and switching difference' are shown in the table1As shown.

table1 Set point deviation and switching difference of electric contact pressure gauge

• The difference between the two readings of the pressure gauge with inspection pointer The difference between the two pointer readings of a double needle double tube or double needle single tube pressure gauge, The difference between the indicated values should not exceed the specified adjustment of the maximum allowable errorUp to this section.

This section introduces the membrane box pressure gauge and electric contact pressureTable.

Diaphragm pressure gauge, also known as micro pressure gauge. Suitable for measuring non explosive hazardsDangerous, non crystalline, non solidifying, and non corrosive to copper and copper alloysLow micro pressure of liquids, gases, or vapors. The membrane box pressure gauge adopts a membrane boxAs a sensitive component for measuring small pressures. Measurement of micro pressure and negative pressure of non corrosive and non explosive gases on copper alloys, widely used inOn other similar equipment such as boiler ventilation, gas pipelines, combustion devices, etc.

Electric contact pressure gauges are widely used in petroleum, chemical, metallurgical, and electrical industriesMeasurement in industrial departments such as stations and machinery, or in supporting electromechanical equipment, with no explosion hazardThe pressure of various fluid media. Usually, instruments are connected to corresponding electrical components

（Such as relays and frequency converters, etc）When used in conjunction, it can be tested（control）Various gases and liquid media under pressure are automatically controlled and generated through instruments信（call the police）The purpose. The electrical contact signal of the electric contact pressure gauge deviceOn the needle, equipped with adjustablepermanentMagnetic steel can increase the suction force of the contact point, addingQuick contact action ensures reliable contact of the contacts, eliminates arcing, and can effectivelyTo avoid instrument contact caused by working environment vibration or medium pressure pulsationFrequent shutdown of points. So the electric contact pressure gauge has reliable operationAdvantages such as long service life and high contact switch power.

2.5 “General Technical Requirements”The changes in the content.

• Cancelled the requirement that the coating of newly manufactured pressure gauges should be uniform and smoothNo obvious peeling phenomenon; The pressure gauge should be equipped with a safety hole, and the safety hole should beThere is a dust-proof device. ”It is stipulated that the visible part of the pressure gauge should have no obviousDefects, scratches, and connectors should have no obvious burrs or damage. ”

For pressure gauges with different measured media, according to oxygen, hydrogenAcetylene, ammonia, and other flammable substances（combustion-supporting）Five types of gases are labeled as "sky" respectivelyBlue, green, white, yellow, and red have cancelled the measurement in the original regulationsThe pressure medium is chlorine, and the color code is brown; Pressure measuring medium surrounding other inert gas cargoLiquid, with a color code of black. The new regulations stipulate that when using colors

When marking, a horizontal line should be drawn below the name of the pressure gauge on the dividing plate,The color of the horizontal line should comply with regulations.

• The two connectors of the double needle double tube or double needle single tube pressure gauge should be connectedApply paint of the same color as the two pointers separately. ”Verified by the original regulationsAdjust the content in 'Methods' to this section.

（2）The markings on the pressure gauge have added the production year and measurement range, Cancelled the vacuum“-”Number or negative character.

• Added a pressure gauge with a set pointer, with the set pointer indicatingThe display end should be able to cover the length of the main dividing line1/4～2/4And with zero adjustmentThe zeroing device of the pressure gauge of the device should be flexible and reliable according to regulations.
• Add clause 'Electrical Safety of Electric Contact Pressure Gauge'Requirement "," Non connectivity between two tubes of dual needle dual tube pressure gauge "and" Oxygen pressureProhibited oil requirements.

• The insulation resistance of the electric contact pressure gauge should be less than20MΩ, DoubleThe two tubes of the needle double tube pressure gauge should not be connected, and the oxygen pressure gauge connector and inner cavity should not be connectedThere should be oil and grease controlled by several pressure gauges in the measuring instrument control of the original regulationsAdjust the content of "Additional Verification" to this section.
• Add clause 'Insulation strength', after verification and repairElectric contact pressure gauge should be able to withstand alternating current（1.5kV,50Hz）Over time1minThe insulation strength test shall not have breakdown or flying fox phenomenon.

2.6“Measurement instrument control”The changes in the content.

• Compensation micro pressure gauge has been added to the available standard instruments for selection，0.05Grade and above digital pressure gauge（Annual stability qualified）, itsThe rated voltage specified in the new regulations for his instruments and auxiliary equipment isDC500VAccuracy level10A level of insulation resistance meter; The frequency is50Hz，The output voltage shall not be lower than1.5kVThe voltage withstand tester has replaced the original standardHigh resistance meter in the process:500V DC，2.5Grade; Safety precautions for ultra-high pressure gaugesCover.
• The new regulations stipulate the measurement of the working medium used for calibrationLimit greater than0.25MPato400MPaThe working medium used for the pressure gauge, However, the original regulations only provided the upper limit of measurement（0.25～250）MPaMedium usedThe regulations.

（3）The new regulations stipulate the inspection, subsequent inspection, and useInspection items in the middle, as shown in the table2As shown.

table2 verification、Subsequent verification and inspection items during use

（4）Comparison of Verification Methods between New and Old Regulations

1）The new regulations provide a schematic diagram of the pressure indication value verification connection, and explain in detail the operation process during verification according to the operating steps: from zero

Starting from the point, apply pressure evenly and slowly until the calibration point is reached（The standard instrumentindicated value）Then read the reading of the inspected pressure gauge（According to the division value1/5estimateread）Lightly tap the shell of the pressure gauge being inspected, read its reading again and record it,The difference between the measured pressure readings before and after tapping lightly and the standard gauge reading is the valueThe indication error of the verification point; This is a one-time inspection at the selected inspection pointCut off the pressure source until the measurement limit is reached（Or vacuum source）, withstand voltage3minAfterwards, perform voltage reduction verification point by point until zero point, with positive and negative pressuresThe membrane box of the power journey（piece）The pressure gauge should display positive and negative pressures separatelyCalibration of indication error of measuring range.

2)Calibration of Electric Contact Pressure Gauge: New Regulations Refine Set Point DeviationPoor verification. In the selection of set points, for different electric contact pressure gauges, chooseRegulations have been made for the selection of points; The detailed operation for determining the up and down switching values.

（1）Comparison of Verification Results Processing

For pressure gauges that fail calibration, the new regulations stipulate the issuance of a calibration result notification, replacing the issuance of a calibration failure notification in the original regulations.

2.7 Comparison of Record and Certificate Formats

（1）In the records of the new regulations, the accuracy of the standard instrument has been addedGrade, measurement range, zero position error of the tested pressure gauge, and stable pointer deflection

Record table of set point deviation and switching difference of sexual and electrical contact pressure gauges, electrical connectionThe insulation resistance of point pressure gauges and the insulation strength of electric contact pressure gaugesrecord.

• New regulations based on verification items（Appearance, zero position error, indicationValue error, return error, tap displacement, pointer deflection stability, otherproject）The internal page format of the verification certificate and verification result notification has been re provided.

3 Conclusion

In summary, the new regulations are more scientific, reasonable, strict, and systematic,In the process of calibrating pressure gauges, it can accurately and effectively guide the actual work of calibrationTo avoid incorrect operating methods caused by differences in personal understanding,It has stronger operability and practical guidance significance for inspectors.