The difference between a fixed pneumatic ball valve and a floating pneumatic ball valve is that the ball of a floating pneumatic ball valve is floating, that is, only the top is equipped with a stem. Under the action of medium pressure, the ball can produce a certain displacement and press against the sealing ring at the outlet end to ensure that the outlet end is sealed, which is a unilateral forced seal. The structure of this pneumatic ball valve is relatively simple, and the manufacturing cost is low. The process pipeline is widely used in the process of use. Due to the compression of the valve seat seal by the medium pressure, the design of the floating pneumatic ball valve should focus on the medium action of the seal ring material. If the medium pressure is too high, the life of the valve seat will be affected, and the ball can only have a slight offset, Therefore, the floating pneumatic ball valve is generally applicable to valves with a diameter of DN200 or below and a nominal pressure not exceeding CLASS600Lb (10.0MPa).

Analysis of hot melt welding procedure of compensator
Hot melt welding steps are as follows:
1. When cutting the pipe, use the pipe cutter vertically. When using other tools (such as fine tooth saw, cutter, etc.) to cut the pipe, remove the burrs deducted. At the same time, use a pen to mark the hot melt insertion depth in the pipe section (the depth of 20 and 25M is about 15MM).
2. Heating pipes and pipe fittings When the hot-melt welder is heated to 260 ℃ (after the indicator light is on), pipes and pipe fittings are simultaneously pushed into the fusion splicer die head, the heating time shall not be less than 5 seconds.
3. Connect the pipes and fittings. Remove the heated pipes and fittings at the same time, and insert them directly to the marked depth at high speed. They can be adjusted properly, but rotation is strictly prohibited.
4. Cool the connected pipes and fittings for 3-5 minutes.
The spherical compensator mainly relies on the angular displacement of the sphere to absorb or compensate the lateral displacement of the pipeline in one or more directions. The compensator should be used in pairs. A single set of compensator has no compensation ability, but it can be used as a pipe universal joint. Therefore, it has the advantages of large compensation ability, small fluid resistance and deformation stress, no blind plate force, and small force on the fixed support. At present, some companies adopt the advanced technology of carbon fiber sealing installation, which makes the sealing performance of the equipment more stable and reliable. Even if leakage occurs during long-time operation, it can be maintained without stopping gas and reducing pressure, and it is very convenient and fast. It has large compensation ability, which is 10 times of the traditional square compensator. Can save investment. It can reduce heat loss and pressure loss, save energy, especially for remote insulation energy, which has obvious economic and social benefits. It has the following advantages:
1 Compensator. It is found during the anti leakage practice that the main leakage point of the spherical compensator is the flange where the spherical compensator is connected to the pipeline, so the connection between the spherical compensator and the pipeline should preferably be welded and flange connection should be minimized. The spherical compensator shall be arranged as close to the elbow as possible, that is, the ball center distance shall be lengthened as much as possible.
2. The compensation interval of anti falling frame ball compensation is long, and the fixed support is stressed heavily. The fixed support must be firm and reliable. The pipe slip bracket must be long enough (when installing, it will shift to the opposite direction of displacement) and have a certain margin to prevent the pipe from overheating. Otherwise, it will lead to problems such as long spacing pipeline sliding bracket.
3. If space permits, it is better to use ball compensation without cold positioning device to ensure safe operation.
4. On the long interval straight pipe section on both sides of the ball bushing, guide brackets shall be set at certain intervals. The movable bracket shall be a rolling bracket or a polytetrafluoroethylene plate shall be padded under the sliding bracket to reduce the friction of the pipeline.
5. When multiple pipes are laid in parallel or small pipes are laid on the back of large pipes, enough space must be reserved in the center of the centralized arrangement of ball compensators to avoid mutual influence of ball compensators and ensure normal and free movement of ball compensators.
6. When the ball compensator is vertically arranged, the first movable support close to the ball compensator must be provided with a spring support (hanger).
7. When three ball compensators are laid overhead for L-shaped pipes, a platform must be set under each ball compensator to install the ball compensator trolley, so as to ensure the free movement of the ball compensator. In addition, a sliding bracket with sufficient length of cross arm shall be set under the elbow of the pipeline to ensure that the sliding bracket of the pipeline will not fall off when the pipeline is thermally displaced.