DESCRIPTION/APPLICATIONS

PG7202 is a member of the PG7000family of reference level piston gaugesthat covers the range of high pressuregas up to 110 MPa (16 000 psi). Operating directly in gas avoidsdifficult to use liquid/gas separatorsthat add uncertainty to the measurementprocess. PG7202's new, gas operated,liquid lubricated piston-cylinderdesign overcomes the disadvantagesof lubricating the piston-cylinder withgas at high pressure. Performance isnot affected by gas cleanliness andpiston drop rates are even lower thanthose typically found in hydraulicpiston gauges.

PG7202 is combined with the GPC1gas pressure controller to configure acomplete calibration system witheffort free gas pressure setting andadjusting (see GPC1 brochure).

GAS OPERATED,LIQUID LUBRICATEDPISTON-CYLINDER

The principle of operation of thePG7202 piston-cylinder is simple butvery effective. The measured gas pressure,Pg, is applied to the bottom of thepiston and to the top of a liquidreservoir located around the cylinder.The reservoir is connected to the gapbetween the piston and the cylinderthrough lateral holes in the cylinder,allowing liquid from the reservoir toenter the gap. The pressure of theliquid in the gap, Pl, is equal to the gaspressure, Pg, plus the pressure resultingfrom the liquid head, h. Therefore,regardless of the gas pressure value,the liquid pressure in the gap is alwayshigher than the gas pressure by theamount of the liquid head. Since h issmall and the space between thepiston and cylinder is typically lessthan 1 micron, the bleed of liquidfrom the bottom of the cylindertowards the gas pressure is minute.By design, any liquid accumulationdrops directly into a deadended sump.

Though liquid may migrate through thegas at the molecular level, no significantcontamination of the test system occurs.As the liquid reservoir is contained in thepiston-cylinder module, the piston-cylindercan be removed and installed in thePG7202 piston gauge platform with noloss of liquid from the reservoir.

All PG7202 piston-cylinder modulescan be delivered using Krytox®, a fluorinated synthetic oil, to lubricatethe piston-cylinder for applications inwhich the system must be free ofhydrocarbons (e.g. when calibratinginstrumentation for oxygen service).

HIGH LINE, DIFFERENTIALPRESSURE

Two PG7202s can be used incombination to define low differentialpressures at elevated line pressures.Contact DHI for more information.

UPGRADES OF TYPE 5200PISTON GAUGES

DH Instruments or Desgrange et HuotType 5200 and 5500 piston gaugescan be upgraded to PG7202 system byinstalling the piston-cylinders in newPG7202 modules and using the existingType 5000 masses. See the data sheet"Piston Gauge Upgrades, 5000 to 7000"for additional information.

NOTE: This brochure provides information specific to the PG7202 model of thePG7000 family of piston gauges. See the PG7000 Reference Level Pressure Standardscatalog for complete PG7000 information.

High PressureGas Piston Gauge

from 100 kPa to 110 MPa (15 to 16 000 psi)PLATFORM

Pg = measured gas pressure Pl = Pg + ρlghPl = liquid pressure Pl > PgPa = atmospheric pressure

PG7000, PG7202, GPC1 and MPC1 are trademarks of DH Instruments, Inc.

PG7000 piston gauges are manufactured under one or more of the following US patents: 5 142 483, 5 257 640, 5 331 838, 5 445 035.

Krytox is a registered trademark of E.I. du Pont de Nemours and Company.

Due to a policy of continual product improvement, all product specifications, descriptions andfeatures are subject to change without notice.

High PressureGas Piston Gauge

from 100 kPa to 110 MPa (15 to 16 000 psi)

© 2002 DH Instruments, Inc. Printed in USA Bro. No. 2010.2.A.3

DH Instruments, Inc.4765 East Beautiful LanePhoenix, AZ 85044-5318USA

Tel 602.431.9100Fax 602.431.9559

dhi@dhinstruments.comwww.dhinstruments.com

PLATFORM

ORDERING INFORMATIONPlatform

Designator Part No. DescriptionPG7202 401297 Gas operated piston gaugePG7202 401298 Gas operated piston gauge,

with motorized piston rotation

Piston-Cylinder ModulesDesignator Part No. DescriptionPC-7200-100 401738 Gas P-C modulePC-7200-200 401739 Gas P-C modulePC-7200-500 401740 Gas P-C modulePC-7200-1 401741 Gas P-C modulePC-7200-2 401742 Gas P-C module

Mass SetsSee page 16 of the PG7000 Piston Gauges catalog.

AccessoriesTo configure a complete PG7202 system, a means of setting andadjusting high gas pressure must be included. MPC1-3000performs this function up to 20 MPa (3 000 psi). GPC1-16000 isused for pressure up to 110 MPa (16 000 psi). A gas booster isused to supply the pressure controller with high pressure byboosting pressure from a standard gas cylinder. See the MPC1and GPC1 brochures for additional information.

Designator Part No. DescriptionMPC1-3000 401210 Manual pressure controllerGPC1-16000 401800 Gas pressure controllerBooster, gas 401002 75:1, with control kitBooster, gas 400509 152:1, with control kit

Contact DHI for information for information on configuring ahydrocarbon free PG7202 system for dedicated use in hydrocarbonfree calibration systems.

LIQUID LUBRICATED, GAS OPERATED PISTON-CYLINDER MODULESAND MASS SETS

Ranges

PC-7200-100PC-7200-200PC-7200-500PC-7200-1PC-7200-2

100 kPa200 kPa500 kPa1 MPa2 MPa

35

153060

153075

150300

5001 0002 5005 000

10 000

0.10.20.51.02.0

3.57.0

17.535.070.0

0.020.040.100.200.40

DESIGNATORPRESSURETO MASS

[p/kg]

MINIMUM PRESSURE*Piston Only

[MPa]Piston & Bell

[psi] [MPa] [psi]

MAXIMUM PRESSURE

35 KG[MPa] [psi]

45 KG[MPa] [psi]

55 KG[MPa] [psi]

80 KG[MPa] [psi]

100 KG

[MPa] [psi]

6501 3003 3006 500

13 000

4.59.0

22.545.090.0

8001 6004 0008 000

16 000

5.511.027.555.0

110.0

1 1502 3005 800

11 75016 000

8.016.040.080.0

110.0

10.020.050.0

100.0110.0

* The minimum pressure point is defined by floating the piston only. Piston mass is 200 g.

† Full mass set cannot be loaded, maximum limited by maximum working pressureof PG7202 platform.

† †

All pistons and cylinders are made of tungsten carbide.

1 4502 9007 250

14 50016 000

[MPa] [psi]

† †

40 KG

6001 2003 0005 900

11 900

4.08.0

20.040.080.0

SPECIFICATIONS

PC-7200-100PC-7200-200PC-7200-500PC-7200-1PC-7200-2

98.149.019.6

9.84.9

NOMINAL AREA[mm2]MODULE

0.100.150.200.250.50

TYPICAL DROP RATE[mm/min]

± (2 Pa + 20 ppm)± (3 Pa + 20 ppm)± (7 Pa + 20 ppm + 0.15 ppm/MPa)± (10 Pa + 25 ppm + 0.15 ppm/MPa)± (20 Pa + 35 ppm + 0.15 ppm/MPa)

MEASUREMENT UNCERTAINTYIN PRESSURE

Piston-Cylinder Module Specifications

All general specifications are identical to other PG7000 piston gauge models(see the PG7000 Piston Gauges catalog).