A slab gate valve is a sliding valve in which the closing members are parallel rams. The closing member may be a single shutter or a double shutter with a distracting mechanism therebetween.
The pressing force of the shutter to the valve seat is controlled by the medium pressure acting on the floating gate or the floating valve seat. If it is a double gate slab gate valve, the expansion mechanism seen by the two gates can supplement this pressing force.
The integral casting bracket stop device positions the assembled bracket valve flap to make the valve seat more stable and reliable.
The valve body has two structures of casting and welding.
The valve seat adopts the O-ring seal and the floating valve seat structure with pre-tightening force to make the valve inlet and outlet bidirectionally sealed; and the opening and closing torque of the structure is only 1/2 of the ordinary valve, which can be easily opened and closed. valve.
The metal-to-metal sealed valve has a grease-injecting structure on the outside of the valve body. The grease enters the valve sealing surface through the grease injector and the valve seat, so that the valve reaches zero leakage.
The valve seat is inlaid with PTFE on the sealing surface, which has the double sealing of PTFE to metal and metal to metal. The PTFE sealing surface also removes the dirt of the gate.
The gate and valve seat are treated by special process, spray-welded hard alloy, wear-resistant PTFE, and achieve double sealing. It can be double-protected with grease-assisted sealing, which is more reliable and has a longer service life.
The ram with the diversion valve is always fully open or fully closed to the sealing surface, and the sealing surface is protected from the direct scouring of the medium, thus prolonging the service life.
When the valve is fully open, the channel is smooth and straight, the flow resistance coefficient is very small, no pressure loss, and the pipeline can be cleaned by the ball.
The valve adopts the packing structure with self-sealing ability, which does not need to be adjusted frequently. It is extremely light and easy to open and close, and the sealing is reliable. The packing letter is provided with auxiliary sealing grease injection structure, the sealing performance is absolutely reliable, and it really reaches zero leakage; The general valve packing is the most vulnerable to leakage.
When the valve is closed, the internal cavity high pressure can be automatically removed to ensure safe use.
Fully enclosed structure, good protection performance, can adapt to all-weather requirements.
The valve is provided with an indicator rod or an observation window to indicate the opening and closing of the valve.
Slab gate valve for occasions
1. (Class 150 ~ 900 / PN1.0 ~ 16.0MPa, working temperature -29 ~ 121 ° C) oil, natural gas transmission pipeline. A slab gate valve with a diversion hole also facilitates cleaning of the line.
2. Transfer lines and storage equipment for refined oil.
3. Oil and gas production wellhead devices, that is, valves for tree trees.
4. Pipes with media with suspended particles.
5. City gas transmission pipeline.
Advantages of slab gate valves
The flow resistance is small, and the flow resistance of the non-shrinking mouth is similar to that of the short tube. A slab gate valve with a diversion hole is installed on the pipeline and can also be cleaned directly with a pig. Since the ram slides on the two valve seat surfaces, the slab gate valve fluid can be applied to the medium with suspended particles, and the sealing surface of the slab gate valve is actually automatically positioned. The seat sealing surface is not damaged by thermal deformation of the valve body. Moreover, even if the valve is closed in a cold state, the thermal elongation of the valve stem does not overload the sealing surface. At the same time, when the valve is closed, the slab gate valve without the diversion hole does not require the high precision of the closed position of the ram, so the electric slab valve can control the opening and closing position by the stroke.
Shortcomings of slab gate valves
When the medium pressure is low, the sealing force of the metal sealing surface is insufficient to achieve a satisfactory seal. Conversely, when the medium pressure is high, if the sealing surface is not lubricated with system medium or foreign medium, frequent opening and closing may cause the sealing surface to wear excessively. Another disadvantage is that the circular ram that moves laterally on the circular flow path is more sensitive to flow control only when it is at 50% of the valve closed position. Moreover, the ram produces severe vibrations when the high speed and high density media flow is broken. It can also be used for throttling if the valve seat is made into a V-shaped port and is closely guided to the shutter.
Flat gate valve selection principle
1. Oil and natural gas transmission pipelines, single-gate or double-grid slab gate valves. If it is necessary to clean the pipeline, use a single ram or double ram with a slab slab gate valve with a diversion hole.
2. For the pipeline and storage equipment of the refined oil, use a single gate or double gate slab gate valve without a diversion hole.
3. Oil and gas production wellhead device, use single-gate or double-gate slab gate valve with diffuser floating valve seat with diversion hole, mostly API 6A standard, pressure level is API2000, API3000, API5000, API10000, API15000 , API20000.
4. For pipes with suspended granular media, use a knife-type slab gate valve.
5. City gas transmission pipeline, single gate or double gate soft seal open bar slab gate valve.
6. Urban water supply project, single-gate or double-grid without guide hole open-plate slab gate valve.
Use of slab gate valve
The slab gate valve is suitable for use in natural gas, petroleum, chemical, environmental protection, urban pipelines, gas pipelines and other transportation pipelines, venting systems and steam storage devices, and is used as an opening and closing device. The Z43 type single-plate slab gate valve with diversion holes is suitable for long-distance pipelines for natural gas extraction and purification.
Slab gate valve diameter range: DN25 ~ 1200 Pressure range: 0.6MPa ~ 45MPa 150Lb ~ 3000Lb
A slab gate valve with a diversion orifice is used for the pipeline that requires the ball clearing pipe, and no diversion orifice is used for the pipeline that does not require the ball clearing pipe.