LEAK TEST OR BUBBLE TEST
Leak test merupakan test untuk
mengecek ada atau tidaknya kebocoroan. Untuk heat exchanger biasanya dilakukan
pada joiny nozzle pad to shell. Leak test dilakukan dengan udara bertekanan
pada pressure yang tidak lebih dari 25% dari design pressure (as per ASME V,
2010) dan cairan sabun. Leak test ini juga sering disebut bubble test.
Untuk holding time leak test,
bersadasrka ASME V dilakukan minimum 15 menit.
Istilah-istilah dalam Leak Test or Bubble Test:
· dew point temperature: that temperature at which the gas in a system
would be capable of holding no more water vapor and condensation in the form of
dew would occur.
·
dry bulb temperature: the ambient temperature of the gas in a
system.
· immersion bath: a low surface tension liquid into which a gas
containing enclosure is submerged to detect leakage which forms at the site or
sites of a leak or leaks.
·
inert gas: a gas that resists combining with
other substances. Examples are helium, neon, and argon.
· instrument calibration: introduction of a known size standard leak
into an isolated leak detector for the purpose of determining the smallest size
leakage rate of a particular gas at a specific pressure and temperature that
the leak detector is capable of indicating for a particular division on the
leak indicator scale.
· leakage: the fluid, either liquid or gas,
flowing through a leak and expressed in units of mass flow; i.e., pressure and
volume per time.
· quartz Bourdon tube gage: this high accuracy gage is a servonulling
differential pressure measuring electronic instrument. The pressure transducing
element is a one piece fused quartz Bourdon element.
· sensitivity: the size of the smallest leakage rate that can be unambiguously detected
by the leak testing instrument, method, or technique being used.
· soak time: the elapsed time between when the desired differential pressure is
attained on a system and the timewhen the test technique is performed to detect
leakage or measure leakage rate.
·
standard dead weight tester: a device for hydraulically balancing the pressure
on a known high accuracy weight against the reading on a pressure gage for the
purpose of calibrating the gage.
· thermal conductivity detector: a leak
detector that responds to differences in the thermal conductivity of a sampled
gas and the gas used to zero it (i.e., background atmosphere).
· vacuum box: a device used to obtain a pressure differential across a weld that cannot
be directly pressurized. It contains a large viewing window, special easy
seating and sealing gasket, gage, and a valved connection for an air ejector,
vacuum pump, or intake manifold.
·
water vapor: gaseous form of water in a system.
