LT5
Setting
Hauser
75
6.4
Handling precautions for water-filling/airtightness
tests and initial operation of the gauge
When accidents such as damage to a measuring tape occur in a high-pressure tank such as
a liquid gas tank, not only do they have a grave impact on the operation of the tank, but
repair work can also be very costly. It has been our experience that most issues involving
damaged measuring tapes arise during the testing phase or in the initial operation of the
tank. To prevent such incidents, be sure to complete the following procedures. By taking
these preventive steps, accidents can be avoided.
• For high-pressure tanks, be sure to keep the gate valve open and set the LT to
measurement mode. Failure to do so may cause the measuring tape to become damaged.
If you notice that the gate valve has not been opened after you started to fill the tank
with water, either drain the water or open the sheave elbow cover and open the gate
valve while applying a brake to the measuring tape with your hand, and allow the LT to
gradually wind the measuring tape.
• For the water-filling test, partially open the water-feed valve and slowly fill the tank
until a depth of approximately 500 to 1
000 mm (19.69 to 39.37 in) is reached.
• Large amounts of water may damage the measuring tape. If the float is in close
proximity to the inlet, install a wave guard so that the float is not affected directly.
• If the test for LT airtightness is performed while the gate valve is opened, make sure the
following components are firmly tightened. If these items are not secure, a large volume
of air may be discharged from the system, causing a high-speed airflow near the gate
valve that will damage the measuring tape.
• Drain plug on the bottom of LT
• Rear cover bolts
• Gland of gauge head rear cover
• Covers for elbows
• When opening the LT rear cover upon completion of the airtightness test, confirm that
the inner tank is either at atmospheric pressure or that the gate valve is closed before
opening LT.
Do not open LT or sheave elbow covers to abruptly discharge the compressed air that has
been built up during the airtightness test. This will damage the measuring tape.
• Be sure to open the gate valve when filling the tank with actual liquids such as liquefied
gas.
Closing the gate valve must be restricted to emergencies or when the surface level is
static.
