USUN Model :GBT7/30    double stage air driven helium  gas pressure pump

for helium cylinder refilling  

Usun air driven gas booster  pumps are ratio devices that utilize low pressure compressed

air driving a larger diameter piston (area x pressure) which is linearly connected to a smaller

hydraulic piston/plunger. Using this ratio principal, a higher hydraulic pressure can be generated.

Usun Pump model numbers reflect the pumps nominal pressure ratio, while the technical data 

indicates exact ratios.  The outlet stall pressure is easy to set by adjusting the air drive pressure

through a simple air pressure regulator. By multiplying the pressure ratio by the available shop

air pressure, the nominal gas  pressure can be calculated.
 

Example ( Pump Model: GBT15/40 Gas booster pump)

Air drive piston area ( 160mm Ø)

Hydraulic plunger area ( 25mm Ø)

Actual ratio = 40:1

 1.  AIR DRIVE SECTION

The air drive section consists of a light weight piston complete with seals running inside an

aluminum barrel. The diameter of the air piston is 160mm. When compressed air is supplied to

the pump the air pushes the air piston down on a compression stroke

(forces as out of the gas end).

 Under the control of pilot pins (poppet valve) triggered at each end of the stroke

2. GAS  DRIVEN SECTION

The gas section of a USUN air driven gas booster consisit of 4 main pieces  

,the gas barrel  ,the piston the check valves  and the main high pressure seals  .

The gaspiston is directly linked to the air piston and it is housedinside the gas barrel 

and its movements up and down creates the gas flow into and out of the booster through

 the check valves . The check valves are psring loaded and on the suction stroke .the inlet check valve

opens to the maximum allowing gas into the gas barrel and on the compression stroke

the inlet check valve closes the discharge check valve opens forcing the pumped gas

 into the process  .The main high pressure seals is located on the gas piston and they seal agaist


 the gas barrel during operation . and the maximum pressures of the pump ,however the

standard PTFE seals are suitable for both the vast majority of gases encountered .

Other materials of construction  can be supplied to meet more aggresive services  

.The standard  serials of booster are not suitable for underground coal mine applications  .

USUN DO Manufacture models of  air driven gas boosters  that are not suitable for underground

coal mine applications .

USUN Air driven gas boosters cycle automatically  as the outlet pressure increass the

resistance also increases and the cycle rate decreases until the pump stops automatically 

when the out put pressure forces are equal .This is refered to as the stall condition  .

The pump will restart with a slight drop in the outllet pressure or an increase in the  air driven pressure 


Booster performance can be affected by a number of conditions ,

such as freezing of the exhaust muffler   or pilot valves ( Which is caused by moisture in

 air lines  ),inadequate  inlet air line sizes and dirty filers .When  operating the boosters 

on a contunuous basis  ,we recommend you use a maximum cycle rate of 50-60 cycles per minute .

This will both  increase service intervals  and assist in preventing ice forming at the exhaust  .

An air supply dryer will also assist in reducing icing up  .

USUN Gas boosters have a 120mm stroke thus reducing cycle rates at any given flow 

and pressure as compared with most other brands  . This lower repsective cycle rate res

ults in a reduction in freeze-up  condition  .

To abtain best overall performance  ,do not reduce the indicated port size and consult

USUN for flow conditions not shown in charts   

Model selection for gas booster  

 It is very important to remember that the performance of any air driven device is very dependent 

on the air supply conditions .Restrictions in the air supply can be caused by using a too small air compressor or 

airlines  .The FLOW CHARTS SHOWN in the technical data sheet are based on good conditions  .

 so please do not "design  to the line "  allow for losses and inefficiencies  

The next question is wheather you want the booster to stall when an outlet pressure is reached 

If so ,a simple airline pressure regulator will suffice ,but remember the flow drops off dramatically as the 

booster reaches a stall condition  .

 If you need the pump to stop at a certain pressure ,prior to stall ,then an air pilor switches needs to be installed  .
 

Key features

 Realiable ,Easy to Maintain ,compact and robust

2. No heat,flame or spark risk

3. Infinitely variable cycling speed and output

4. Air driven Models do not require electrical connection ,easy to apply automatic controls

5. No limit or adverse affect to contineous stop/start applications

6.Seals system designed for long working life,No airline lubricated required

7.Built-in coupling system (Most models) and suitable for most gases boosting 

Main technical data  





Typical technical data for double stage air driven gas booster pump  

 Remark 1) Maxium outlet pressure are at an air driven pressure of 8 bar or 116 PSI ,for long life using

of such pump ,we suggest that air driven pressure should be not more than 8 Bar  .

Typical application of such double stage air driven gas booster pump  




Factory pictures