Leakage Testing By Back Pressure Method :
The job to be tested is placed on ss fixture as shown . The outlet is plugged so no air shall pass thorough. At inlet we pump the desired air pressure from 0 to 5 bar for a fixed period say 30 sec . Then we stop the pumping of air.
Now we compare the inlet pressure with pressure job has. The difference in pressure is shown on scale. With deflection electronic system glows red light for leakage and green light for ok. job.
Liquid dip method :
The job to be tested is pumped with desired pressure through
inlet, which is indicated on pressure dial gauge. The outlet of
job is plugged and made airtight. The job is forcefully dipped
into liquid medium with desired pressure in it. If leakage is
present there will be air bubbles in liquid medium. Thus we can
obtain location of leakage.
For checking any valve assembly, pump assembly and various
types of castings.