Airtightness test of the airbag

First combine the inflatable parts of the air bag, such as the air pump, pressure gauge, high pressure hose, after the combination is completed, it is necessary to check the leakage of the tool. Then use the air pressure pump to inflate the air bag, the air pressure shall not exceed 0.015Mpa, watch whether the reading of the barometer changes, if the reading of the barometer does not change, it proves that the air bag is not permeable and the air tightness is good.

Airbag construction

After the airtightness inspection of the airbag is completed, the impulse force generated by the flowing water in the well and the pressure generated by the water in the well are calculated during the construction of the airbag. After the airbag is inflated in the air bag, the airbag expands so that the airbag is closely embedded in the circular tube and remains motionless under the action of the external water pressure and impulse force, resulting in water blocking and not leaking.

Air bag construction process: test the performance and air tightness of each component → combine the air bag accessories → test the air tightness → Open the pipeline to check the well head, place and fix the air bag → pump air into the air bag → observe the pressure value of the air bag

Air bag accessories for combination construction

The air bag accessories assembly installs the air compressor first, and makes it fixed after placing, connects the needle valve to the air compressor, and then connects two tees, one of which installs the pressure gauge of the air compressor, the other tee installs the pressure gauge of the air bag, connects the high pressure hose at the left back, and fixes it on the air bag with a brown rope.

Install and fix air bags

The airbag should be folded before installation, but it should be noted that dragging the airbag is not allowed in the process of moving the airbag, and the site should be cleaned up in advance, and hard debris is not allowed on the ground to prevent damage to the outer wall of the airbag.

Install the airbag on the pre-welded tripod. Use steel wire and brown rope at the junction of the air bag and the high pressure hose, place the air bag and the high pressure hose, and make the rope head smooth so that it is fixed on the ground.

Open the well cover of the inspection well, and slowly put the air bag into the pipe mouth of the inspection well from the hole, but be careful not to put the air bag at the pipeline joint, for the following reasons:

(1) There are joints in the inner wall, affecting the tightness of water plugging;

(2) So as not to expand the air bag to one side, the air pressure can not go up, if continue to inflate, the air bag will be broken;

(3) For municipal drainage pipes, the sand is required to be clean, the inner wall is smooth, and no burrs are allowed, otherwise it will affect the sealing of water plugging and puncture the air bag;

(4) Various specifications of air bags are used in the corresponding pipeline, and can not be small.

When the air compressor is used to inflate the air bag to complete, the gas volume of the air compressor should be turned down a little, and a large amount of inflation should not be continued to prevent the air bag from breaking and causing accidents. In the process of inflating the air bag, check whether the pressure of the air bag has a significant change, at the beginning of every 1 hour, and after the completion of the air bag pressure gauge has no change can be checked every 2 hours.

In the engineering operation, we should always pay attention to the pressure value of the air bag. If the pressure value of the air bag is dropping slowly, it is unnecessary to stop the operation and continue to use the air pump to give the air bag standard air pressure, and check the air bag after the operation is completed.