These pumps are similar to Hand Pump, except that the Handle is substituted with Pneumatic Cylinder, Air Pressure is fed at the input port of the pump which actuates built in cylinder and thereby piston of the pump.
Lubricating oil with fixed quantity & pressure of 15 kg/cm sq. is discharged from the outlet whenever air pressure is maintained 5-7 kg. per sq cm. maintained in the pneumatic line. For recharging of the pump for next impulse, pressure in Pneumatic line must be dropped down to zero.
These pumps can be successfully used as Automatic Lubrication System with the help of direction control valve and electronic timer.