3. OPERATION
Page 13
©1998-2008 DH Instruments, a Fluke Company
3
3
.
.
O
O
P
P
E
E
R
R
A
A
T
T
I
I
O
O
N
N
3.1
GENERAL OPERATING PRINCIPLE AND INFORMATION
Refer to Figure 3.
The purpose of the GB booster is to automatically boost gas pressure to very high pressure.
The value of very high pressure that is generated depends on the drive air pressure setting. The unit
generates high pressure using a Pneumatically Operated Gas Booster Pump and a Drive Air
Control Kit.
GAS BOOSTER PUMP
The booster pump is a Pascal press utilizing two pistons connected together on the same axis having a
normal area ratio of 75:1 (GB-75) or 152:1 (GB-152). The booster is a two-stroke, single stage
reciprocating pump that generates gas pressures 75 or 152 times greater than the shop drive air applied
to the pump. The pump operates automatically, provided drive air is supplied to the
DRIVE ADJUST regulator
and the regulator is set to at least 140 kPa (20 psig). Operation is continuous
until the outlet pressure is 75 (GB-75) or 152 (GB-152) times the shop drive air pressure.
At this point, the opposing forces within the pump reach equilibrium and the pump stalls. For example,
using a GB-75 with the drive air pressure set to 500 kPa (73 psig), the pump will run until the high
pressure output reaches 75 x 0.5 = 37.5 MPa (5 450 psig).
1. The Shop Drive Air section (low pressure) 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.
2. The high pressure section (high pressure) consists of a small piston and an inlet/outlet check valve
assembly. The small piston moves forward and backward with the air drive piston. During the
suction stroke (backward movement), the outlet check valve closes and the inlet check valve opens
letting supply high pressure gas enter the compression chamber. During the compression stroke, the
inlet check valve closes and the outlet check valve opens letting boosted gas out of the pump.
The compression ratio of the high pressure piston is 25:1 (for both models). Maximum output
pressure is limited by the instrument gas supply pressure. For example, with 2 MPa (300 psi)
applied, maximum output pressure cannot exceed 2 x 25 = 50 MPa (7 500 psi).
3.2
OPERATION
Once the gas booster has been set up and the initial start up is completed, operation is very simple.
There are two possible operator actions:
•
Setting the booster output pressure (see Section 3.2.1).
•
Turning the booster ON and OFF (see Section 3.2.2).
