Valve

Abstract

The invention discloses a valve. Sealing surfaces of a valve plate and a valve seat of the valve are positioned on matched or attached shaft end surfaces of the valve plate and the valve seat; a mechanical transmission mechanism is connected with an actuating mechanism through a rotating shaft; a rectangular frame is arranged on the inner side wall of the valve plate; the central axis of the rectangular frame is parallel to both the valve plate and the rotating shaft, and the rotating shaft penetrates through the rectangular frame; the mechanical transmission mechanism comprises a cam and a rectangular sliding block; the cam is fixed on the rotating shaft, and the working profile of the cam comprises two sections of involutes or spirals S1 and S2 which are opposite in direction; and the rectangular sliding block is arranged on the rotating shaft in a sleeving mode, can rotate freely and is fixed in the axial direction of the rotating shaft. The valve is good in sealing effect, compactin structure, few in spare and accessory parts and economical in cost, and can be widely applied to various shaft end face sealing structures.

Description

technical field [0001] The invention relates to a valve, in particular to a valve in which the sealing surfaces of the valve plate and the valve seat are at the position of the axial end surfaces where the valve plate and the valve seat are mated with each other. Background technique [0002] There are many types of valves. Common such as butterfly valves, the sealing part is along the radial direction of the valve plate and valve seat, so high requirements are put forward for the radial machining accuracy of the two. When this type of valve is large in size, it is difficult to achieve zero leakage. In order to reduce leakage, soft seals are used in some occasions. The disadvantage of using soft seals is that the seal will be affected after the soft seal material is worn out when the switch is switched or the medium washes. In addition, when the materials of the valve body and the valve plate are different or the valve body needs to be lined with thermal insulation, a diff...

AI Technical Summary

Problems solved by technology

Therefore, there are many internal components and the cost is high. When used in high-temperature applications, more high-alloy steel or precious metal materials are required, which further increases the cost.

[0009] (2) It is difficult to ensure the relative position of the four shaft holes and the relative position between the valve plate and the valve seat, which puts forward very high requirements on the machining accuracy of many parts, and there are many parts to be machined, which further increases the manufacturing cost

[0010] (3) There are many parts and friction pairs, which affect the possibility of use

[0011] (4) The torque required to switch the valve plate is large

[0012] (5) The lengths of each crank and connecting rod are different. When used in high temperature applications, the thermal expansion difference of each component is relatively large, which will cause displacement and rotation of the valve plate, which will affect the sealing performance and cause leakage.

[0014] (1) Two sets of transmission mechanisms composed of a rotating shaft, a shaft tube and two sets of racks and pinions are used, the structure is complex, the cost is high, and the reliability of use is affected

[0015] (2) A butterfly sleeve with a valve plate is used. The butterfly sleeve is larger than the valve plate and occupies the space in the valve. This will inevitably reduce the overall size of the valve plate, and then reduce the inner diameter of the valve seat, which will bring greater pressure. loss, increasing the energy consumption of the conveying medium

[0016] (3) For a valve of DN3000, the diameter of the valve plate is close to 3000, and the diameter of the butterfly sleeve is close to 3000, which is almost equivalent to two valve plates, which wastes a lot of raw materials invisibly, which will increase a lot of cost. Using expensive high-alloy steel, this alone will increase a lot of material and machining costs

[0017] (4) The sealing ring and sealing components on it also make the structure complicated

[0018] (5) There is a balance hole on the valve plate, and there is a balance cavity between the valve plate and the butterfly sleeve. Whether it is a gas or a liquid medium, when solid impurities in the medium enter the balance cavity, it will affect the relative relationship between the valve plate and the butterfly sleeve. movement, causing the valve plate to fail to switch

[0020] (1) The horizontal displacement of the spool is actually pressed or loosened by the convex contour on the transmission part, and then the elastic ribs 82 and 83 push the spool to rotate left and right around the ball head at the upper end of the connecting part. The problem is that the valve stem is not a whole piece, and the valve core is supported by the shaft on the handle and the ball head on the connecting piece, which is equivalent to the valve core being supported by two cantilever beams, which affects the strength. Under the action, it is easy to produce large deformation, which will affect the sealing

In addition, a spherical surface needs to be processed for one end of the connector, which increases the manufacturing cost

[0021] (2) This transmission mechanism cannot be used for butterfly valves with flat seals, because the valve core does not have overall horizontal displacement

[0022] (3) The elastic ribs adopted in this invention are to reduce the friction force during transmission, that is, the elastic force is not large, which will cause two problems: one is when the medium pressure is slightly larger, and at the same time the flow direction of the medium, the valve When the spool is located upstream of the valve seat, it is difficult to make the spool shift when it is opened by relying on the elastic ribs with little elasticity.

The other is that when the valve is used in a pipeline perpendicular to the ground and the spool is above the valve seat, since the spool of the large valve is heavy, it is difficult to lift the spool by the elastic ribs with little elasticity.

[0023] (4) When used in high temperature occasions, the elastic force of the elastic ribs on the transmission parts drops sharply, especially in the occasions mentioned in the above article 3, it is almost unusable

[0024] (5) The transmission part is an outer cam plus two elastic ribs with complex shapes on it, and an inner cam is processed on the inside of the valve core, which is equivalent to two cams, and one end of the connecting part needs to be processed with a spherical surface , leading to an increase in manufacturing costs and post-use maintenance costs

[0025] (6) The shape of the transmission part is complex and the processing cost is high

[0026] (7) The spool and the valve body have a blocking structure at the bottom, which further complicates the structure

[0030] (3) If the spring force of the plate spring is too large due to the heavy valve plate, it is difficult to open the valve and the initial stage of opening is more likely to make the valve plate rotate first. Since the valve plate extends into the valve seat, at this time, it will cause the valve Can't open normally

[0031] (4) When the size of the valve is large and used in high temperature occasions, the leaf spring and the leaf spring seat will use more expensive high-alloy steel, resulting in a sharp increase in cost

For a valve with a nominal diameter of DN2400, an operating temperature of 680°C, and a zero leakage rate, the weight of the valve plate is about 3 tons. It can be seen that the torque required to switch the valve plate is large

[0040] (2) In order to control the movement track of the valve plate, a guide plate and a guide shaft are set. When the cam (crank) lifts the valve plate, the force point between the movable plate and the cam deviates greatly from the center line of the valve body. The center of gravity of the internal parts has a large deviation in the horizontal direction relative to this stress point. The upward thrust of the cam (crank) makes the guide shaft generate a thrust on the guide plate. Since the valve plate is heavy, the friction force is relatively large. This requires a large torque of the actuator, which increases the cost

This bracket requires many parts, which makes the structure of the valve complex and increases the cost. Many of these added parts need to be machined, which further increases the cost

[0044] (6) When the valve is closed, the pressing point of the cam (crank) is far away from the center of the valve plate, and the entire sealing surface cannot be evenly pressed, which affects the sealing. Therefore, a larger actuator is required. Considering the strength, some parts As the size increases, these all bring about an increase in cost

[0045] (7) There is a fan-shaped curved surface on the guide plate, which needs to be machined, which also increases the cost

[0047] (9) The fatal problem still existing in the above-mentioned patented technology is: when it is used in a higher temperature occasion, the size of each component is different, the thermal expansion difference is large, and the expansion coefficient of different materials is also different, which will cause interference when switching , after the fan-shaped curved surface on the guide plate is thermally expanded and deformed, the valve is very likely to fail to open

Second, when there is no medium, the guide plate does not expand radially, and the valve cannot be opened

Moreover, there are also a series of problems such as the aforementioned complex structure.

In addition, there is also the problem that the bracket expands radially along the valve body

[0048] (10) After the valve disclosed in the above patent is opened, its soft seal will be washed by the medium, thus affecting its service life

Images