In order to ensure the safe operation of the pipeline network, and take into account the needs of maintenance and wiring, the necessary auxiliary equipment is set up at the appropriate location of the pipeline. These devices include valves, insulating joints, compensators, drains, discharge pipes, valve wells, etc.
1) Valve
Before installation, the strength and tightness test should be carried out according to the requirements of the product standard, and the qualified ones should be marked (the safety valve should be sealed), and the unqualified ones shall not be installed.
Problems that should be paid attention to when installing valves:
(1) Directionality: There are signs on the valve body of the general valve, and the direction pointed by the arrow is the flow direction of the medium, which must be paid special attention to and must not be reversed. Because there are many kinds of valves that require one-way flow of medium, such as safety valves, pressure reducing valves, check valves, etc. In order to facilitate opening and maintenance, the shut-off valve also requires the medium to pass through the valve seat from the bottom up.
(2) The installation position should be convenient for operation and maintenance, and at the same time, it should also take into account the beautiful appearance of the assembly, the valve handwheel should not be downward, to avoid the operation of the face on the back; the landing valve handwheel should be upward, not skewed; under the premise of the process, the valve handwheel should be located at chest height, so as to open the valve; the open rod gate valve should not be installed underground, in order to prevent corrosion. Some valves have special requirements for installation locations, such as pressure reducing valves that need to be installed upright on horizontal pipes without tilting, and safety valves that should also be installed vertically.
5. [Single Choice] Regarding the statement about the gas pipeline discharge pipe, the wrong thing is ( ).
A. Used to discharge the air inside the pipeline B. Used to discharge the gas inside the pipeline
C. It should be installed before the valve (according to the direction of gas flow) D. The ball valve on the discharge pipe should be opened when the pipeline is operating normally
6. [Multiple choice] Regarding the installation requirements of auxiliary equipment of the gas pipeline network, the correct ones are ( )
A. When there is an arrow mark on the valve, it should be installed according to the flow direction of the medium B. The compensator should be installed on the upper side of the valve according to the direction of air flow
C. The drain cover should be installed in the center of the drain well, D. The discharge pipe should be installed at the lowest point and after each valve
E. The valves on the underground gas pipelines are generally set outside the valve wells