3. OPERATION
Page 9
© 2008 DH Instruments, a Fluke Company
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3.1
GENERAL OPERATING PRINCIPLE AND INFORMATION
Numerical references in this section refer to Figure 2.
The purpose of the GB-H-152 booster package is to provide a regulated high pressure gas output with
enough flow to assure a continuous supply to a high pressure gas controller/calibrator such as PPCH-G
when it is increasing pressure. The system generates high pressure using a pneumatically operated gas
booster pump (11), a drive air regulator and shutoff valve (15, 13) and an accumulator volume (9).
Pressure ports are provided to connect the drive air input (16), test gas input (1) and high pressure output
(8). A drive air output connection (17) is also provided as a convenient way to connect drive air to
another point of use such as the
DRIVE
port of a PPCH-G pressure controller/calibrator. The system is
contained in one compact unit and is ready to operate once gas supplies are connected and regulators
are properly adjusted.
3.1.1
PNEUMATICALLY OPERATED GAS BOOSTER PUMP (11)
The booster pump is a Pascal press utilizing two pistons connected together on the same
axis having a nominal area ratio of 152:1. The booster is a two-stroke, single stage
reciprocating pump that generates gas pressures 152 times greater than the shop drive air
applied to the pump.
The pump operates automatically, provided drive air is supplied to the drive air regulator (15)
and the regulator is set to at least 140 kPa (20 psig). Operation is continuous until the outlet
pressure is 152 times the drive air pressure. Then the opposing forces within the pump
reach equilibrium and the pump stalls. For example, with the drive air pressure set to 0.6
MPa (90 psig), the pump runs until the instrument gas pressure downstream of the booster
reaches 152 x 0.6 = 91.2 MPa (13 224 psig). Note that the high pressure section of the
pump has a nominal compression ratio of 25:1. Therefore, the pressure generated by the
booster cannot be greater than the test gas supply pressure x 25. If the test gas supply
pressure is not high enough to reach the desired output pressure, the booster will run
continuously but the pressure will not increase.
1. The drive section (low pressure) of the booster consists of a piston, cylinder, air cycling
valve, pilot valve and vent section. This section provides the reciprocating action and
compression force needed to operate the booster and generate the high pressure gas.
Drive air is channeled to the appropriate side of the piston (compression or suction
stroke) by the air cycling valve. When the piston reaches full stroke, a pilot valve is
mechanically activated causing the air cycling valve to change position. Shop drive air is
routed to the opposite side of the piston reversing piston direction where a second pilot
valve is activated repeating the process.
