A damping swing check valve

Abstract

The utility model provides a kind of damping lift check valve, effectively prolongs the service life of product, by valve body, valve clack, piston chamber, valve stem, piston, valve cover and the like component composition, its characterized in that: piston chamber adopts waist type structure, and sealing surface is machined in piston chamber lower end, and the form pressure cavity is formed after cooperation with valve clack, recess is machined in piston chamber upper end, and the damping cavity is formed after cooperation with valve cover, and multiple through holes are machined in the waist of piston chamber and upper part, for medium flow into pressure cavity and damping cavity, the damping cavity is divided into damping upper chamber and damping lower chamber, and piston is not contacted with damping cavity wall on entire opening-closing stroke;Valve stem is connected by gland with valve clack, and valve stem passes through the middle through hole of piston chamber, and valve stem can be guided to move up and down in through hole, and the upper end of valve stem is machined with screw thread, and piston is connected and fixed with valve stem by nut;Valve body, piston chamber, valve cover adopt bolt connection and fix.

Description

Technical Field

[0001] This utility model relates to a damping lift check valve, which uses medium pressure to provide the initial closing force, and can play a slow closing function during the valve disc closing process, avoiding the valve disc from rapidly impacting the valve body sealing surface when closing, thus preventing damage to the sealing surface and improving product performance. Background Technology

[0002] Currently, lift check valves used in industries such as nuclear power, electric power, petrochemicals, and metallurgy all use springs to provide the initial closing force. During the valve closing process, under the action of spring force and medium force, the valve disc closes quickly, and the valve disc sealing surface directly impacts the valve body sealing surface rapidly, which can easily lead to damage to the sealing surface, reduce the service life of the product, and even cause leakage problems. Summary of the Invention

[0003] This utility model provides a damped lifting check valve that uses medium pressure to provide the initial closing force and has a slow-closing function for the valve disc. This avoids the valve disc from rapidly impacting the valve body sealing surface during closing, thus preventing damage to the sealing surface and improving product performance. The technical solution of this utility model is as follows: It consists of a valve body, valve disc, piston chamber, valve stem, piston, valve cover, and other components. The piston chamber has a waist-shaped structure with a sealing surface machined at its lower end, forming a pressure chamber when it mates with the valve disc. A groove is machined at the upper end of the piston chamber, forming a damping chamber when it mates with the valve cover. Multiple through holes are machined in the waist and upper part of the piston chamber for medium flow into the pressure chamber and damping chamber. The damping chamber is divided into an upper damping chamber and a lower damping chamber. The piston does not contact the damping chamber wall during the entire opening and closing stroke. The valve stem is connected to the valve disc via a pressure cap, and the valve stem passes through the central through hole of the piston chamber, allowing for vertical guidance within the through hole. The upper end of the valve stem is threaded, and the piston and valve stem are fixed together by a nut. The valve body, piston chamber, and valve cover are fixed together by bolts.

[0004] After the valve opens, the medium enters the pressure chamber and damping chamber through the piston chamber orifice, and the valve is in a pressure equilibrium state. When the pressure at the valve inlet decreases, a pressure difference is formed above and below the valve disc because the pressure inside the pressure chamber remains high. Under the action of the medium pressure, the valve disc begins to close. The piston follows the valve disc in its closing motion, at which point the medium in the damping chamber moves from the lower damping chamber to the upper damping chamber. The entire closing process is divided into two stages. In the first stage of closing, due to the large gap between the piston and the damping chamber wall, the medium in the damping chamber can be transferred from the lower damping chamber to the upper damping chamber almost without resistance. In the second stage of closing, the gap between the piston and the damping chamber wall is very small, the resistance of the medium in the damping chamber moving from the lower damping chamber to the upper damping chamber increases, the piston descends more slowly, and the valve disc achieves a slow-closing function.

[0005] Technical features: The initial closing force is provided by the medium pressure, it has a slow closing function, long service life, simple structure, and convenient maintenance. Attached Figure Description

[0006] The present invention will be further described below with reference to the accompanying drawings and examples.

[0007] Figure 1 This is a schematic diagram of a piston-type slow-closing check valve. In the diagram: 1. Valve body, 2. Valve disc, 3. Gland, 4. Piston chamber, 5. Valve stem, 6. Piston, 7. Valve cover, A. Pressure chamber, B. Lower damping chamber, C. Upper damping chamber.

[0008] Figure 2 This is a schematic diagram of the piston chamber. In the diagram, 8 represents the through hole and 9 represents the groove.

[0009] Figure 3 This is a schematic diagram of the first stage of closing a piston-type slow-closing check valve. In the diagram, A represents the pressure chamber, B represents the lower damping chamber, and C represents the upper damping chamber.

[0010] Figure 4 This is a schematic diagram of the second stage of closing a piston-type slow-closing check valve. In the diagram, A represents the pressure chamber, B the lower damping chamber, and C the upper damping chamber. Detailed Implementation

[0011] exist Figures 1-2 In the illustrated embodiment, valve disc 2 and valve stem 5 are connected and fixed by a pressure cap 3. Valve stem 5 passes through the central through hole of piston chamber 4 and can move up and down within the through hole. Threads are machined on the upper end of valve stem 5. Piston 6 and valve stem 7 are connected and fixed by a nut. Valve body 1, piston chamber 4, and valve cover 7 are connected and fixed by bolts. A sealing surface is machined on the lower end of piston chamber 4. When the valve is opened, valve disc 2 contacts piston chamber 4 to form pressure chamber A. A groove 9 is machined on the upper end of piston chamber 4. After piston chamber 4 and valve cover 7 are fitted together, a damping chamber is formed. The damping chamber is divided into a lower damping chamber B and an upper damping chamber C. Piston 6 does not contact the damping chamber wall during the entire opening and closing stroke. Multiple through holes 8 are machined on the waist and upper part of piston chamber 4 for media to flow into pressure chamber A and damping chamber.

[0012] exist Figures 3-4 In the illustrated embodiment, during the first stage of closure, the pressure at the valve inlet decreases. Since the pressure in pressure chamber A remains high, a pressure difference is created above and below valve disc 2, causing it to close under the pressure of the medium. Piston 6 follows valve disc 2 in its closing motion. At this time, the medium in the damping chamber enters from the lower damping chamber B to the upper damping chamber C. Due to the large gap between piston 6 and the damping chamber wall, the medium in the damping chamber can be transferred from the lower damping chamber B to the upper damping chamber C almost without resistance. During the second stage of closure, the gap between piston 6 and the damping chamber wall is very small, increasing the resistance of the medium in the damping chamber from the lower damping chamber B to the upper damping chamber C. This slows the descent speed of piston 6, achieving the slow-closing function of valve disc 2.

Claims

1. A damped lift check valve, comprising a valve body, a valve disc, a piston chamber, a valve stem, a piston, and a valve cover; characterized in that: The piston chamber adopts a waist-shaped structure. The lower end of the piston chamber is machined with a sealing surface, which forms a pressure chamber after cooperating with the valve disc. The upper end of the piston chamber is machined with a groove, which forms a damping chamber after cooperating with the valve cover. Multiple through holes are machined in the waist and upper part of the piston chamber for the medium to flow into the pressure chamber and the damping chamber. The damping chamber is divided into an upper damping chamber and a lower damping chamber. The piston does not contact the damping chamber wall during the entire opening and closing stroke. The valve stem and valve disc are connected by a gland. The valve stem passes through the central through hole of the piston chamber and can move up and down within the through hole. The upper end of the valve stem is threaded. The piston and valve stem are connected and fixed by a nut. The valve body, piston chamber, and valve cover are fixed by bolts.

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