General Information for Air driven liquid pumps

USUN air driven liquid  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 liquid pressure can be calculated.

Exmple ( Pump Model: AT644 liquid pump)

Air drive piston area ( 160mm Ø)

Hydraulic plunger area ( 20 mm Ø)

Actual ratio = 64:1


 

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 80mm. When compressed air is supplied to

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

( forces fluid out of the liquid end).

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

 

2. HYDRAULIC SECTION (Wetted End)

The hydraulic section of an air driven liquid pump consists of 4 main pieces, the hydraulic body,

the piston/plunger, the check valves and the main high pressure seal. The hydraulic

piston/plunger is  directly linked to the air piston and it is housed inside the hydraulic body and

its movement up and down creates the liquid flow into and out of the pump through the check

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

 opens to the maximum allowing fluid into the hydraulic body and on the compression stroke the

inlet check valve closes and the discharge check valve opens forcing the pumped fluid into the

process. The main high pressure seal is located within the hydraulic body and the piston/plunger seals

against this during operation. There are different materials and designs of high pressure seals

depending on the fluid being pumped and the maximum pressures of the pump, however the

standard seals are suitable for both water and hydraulic fluid use.

USUN air driven liquid pumps are self-priming, However, high ratio pumps are more difficult to

Prime and may require bleeding. In general, it is not recommended to use an air- line lubricator.

USUN  air driven liquid pumps cycle automatically  as the outlet pressure increases the

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

when the output  pressure forces are equal. This is referred to as the stall condition.

The pump will restart with a slight drop in the outlet pressure or an increase in the air drive

pressure. Pump 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 pumps on a continuous 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.

To obtain best overall performance, it is recommended not to reduce the indicated port sizes

and consult We for flow conditions not shown in charts.

Typical applications for  pneumatic driven water testing pump  



Key features

One model available in 8 ratios

Compatibility with a variety of liquids

Safe pneumatic operation

Aluminum bodies and wetted materials of carbon steel or stainless steel

Rugged,compact,reliable and easy maintenance proven design

High quality seals, long service life available

No need for air line lubrication

Wide application with large range of pressure ratio

Main technical data 








Typical technical data for air driven Liquified CO2 pumps  
 

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 diagram of such air driven liquified CO2 pumps 


 

Product Applications 




 

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