A lifting check valve capable of reducing the harm of water hammer

Abstract

A lifting check valve capable of reducing the harm of water hammer, comprising a valve body, a valve seat, a valve cover, a bushing, a valve core, a compression spring and the used seals and connectors. Its special feature is that: inside the sealing end of the valve core of the lifting check valve, there is a small check valve sealed with small steel balls. The small check valve is composed of the sealing end of the valve core of the lifting check valve as the valve body, adding an external hexagonal hollow plug and a combination of small steel balls. At the inlet of the small check valve, there is also an internal hexagonal hollow plug and a filter screen installed. When the water hammer phenomenon occurs, pressure is relieved through the small check valve, thereby reducing the water hammer phenomenon and harm; compared with other measures to prevent and reduce the water hammer phenomenon, it has the advantages of not increasing the volume of the original equipment or pipeline and having the lowest cost.

Description

Technical Field

[0001] The present invention relates to a check valve in industrial machinery, fluid equipment or pipelines. Background Art

[0002] In fluid equipment such as petrochemical industry, steam power generation, water supply and drainage, there inevitably exist phenomena of flow velocity change and pressure fluctuation; especially in fluid equipment or pipelines equipped with check valves, the water hammer phenomenon caused by the sudden closing of the check valve is even inevitable. The abnormal pressure generated by water hammer has a great impact on the equipment or pipeline. It can cause severe vibration and deformation at least, and can cause damage to parts and accidents at worst. Although people can take measures such as installing safety valves, exhaust valves, steam traps or accumulators in the equipment or pipeline, shortening or thickening the pipeline, and slowly opening and closing the valve to reduce the water hammer phenomenon and its harm; but the implementation of these measures will be restricted by many objective factors and will significantly increase the manufacturing cost of the equipment or pipeline. Therefore, taking technical measures on the check valve itself is the most direct and effective method to reduce costs and mitigate harm. Summary of the Invention

[0003] The purpose of the present invention is to provide a lift check valve with simple structure, economic practicality and capable of reducing the harm of water hammer.

[0004] The present invention includes a valve body, a valve seat, a valve cover, a bushing, a valve core, a compression spring and the used seals and connectors. The special feature is that: inside the sealing end of the lift check valve core, there is a small check valve sealed with small steel balls.

[0005] The small check valve sealed with small steel balls is composed of the sealing end of the lift check valve core as the valve body, adding an external hexagonal hollow plug and small steel balls.

[0006] At the inlet of the small check valve, there is also an internal hexagonal hollow plug and a filter screen installed.

[0007] Since the present invention has a small check valve sealed with small steel balls inside the sealing end of the lift check valve core; when the lift check valve closes suddenly due to a sudden change in fluid pressure, the liquid flowing in the original pipeline, under the action of inertia, concentrates its energy towards the lift check valve, generating a water hammer phenomenon. If the fluid pressure several times higher than the normal working pressure cannot push open the valve core of the lift check valve to relieve pressure, it can push open the small steel balls in the valve core and relieve pressure through the small check valve, thereby reducing the water hammer phenomenon and its harm and avoiding damage to the check valve and the equipment or pipeline where it is located. When the water hammer phenomenon disappears, the lift check valve still maintains its original working state.

[0008] If the liquid in the equipment or pipeline contains uneven or large-particle impurities, a filter screen is installed at the inlet of the small check valve to prevent the small check valve from being blocked. Description of the Drawings

[0009] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0010] Figure 2 is the present invention Figure 1 at location A in the present invention, an enlarged schematic diagram of the structure of the small check valve;

[0011] Figure 3 is a part in the small check valve of the present invention: an enlarged axial projection of the inner end of the external hexagonal hollow plug.

[0012] The names of the components indicated by the reference numerals in the accompanying drawings are as follows:

[0013] 1. Valve body, 2. Valve seat, 3. Stud, 4. Nut, 5. Sealing gasket ring, 6. Valve cover, 7. Bushing, 8. Valve core, 9. Compression spring, 10. External hexagonal hollow plug, 11. O-ring, 12. Small steel ball, 13. Internal hexagonal hollow plug, 14. Filter screen. Detailed implementation manners

[0014] The present invention will be further described below in conjunction with the accompanying drawings:

[0015] The present invention is composed of a high-pressure resistant lift check valve commonly used in oil and gas drilling and production equipment, and a small check valve sealed by a small steel ball 12 added inside the sealing end of the valve core 8 of the lift check valve; under normal circumstances, an internal hexagonal hollow plug 13 and a filter screen 14 are also installed at the inlet of the small check valve.

[0016] The lift check valve of the present invention includes special parts: valve body 1, valve seat 2, valve cover 6, bushing 7, valve core 8 and compression spring 9, seals: gasket ring 5 and O-ring 11, connectors: stud 3 and nut 4. The valve body 1 is a three-way part. The middle is a cylinder, and the left and right ends extend with necked flanges for external connection. Inside the middle cylinder, from top to bottom, there is a blind hole valve cavity composed of an upper cylindrical hole, a tapered hole in transition, and a lower cylindrical hole. The upper end face of the middle cylinder is machined with a trapezoidal gasket ring groove and evenly distributed threaded blind holes for connection with the valve cover 6. The necked flanges at the left and right ends are respectively machined with left and right flow passage holes communicating with the lower cylindrical hole and the upper cylindrical hole of the valve cavity. The two end faces of the flange are machined with trapezoidal gasket ring grooves and evenly distributed bolt holes for external connection. The valve seat 2 of the present invention is made of anti-corrosion and wear-resistant hard alloy material, welded on the tapered hole in transition in the valve cavity of the valve body 1, and the wall thickness after machining should be greater than 2 mm to ensure its service life and effect. The valve cover 6 is the same as the valve cover part of the existing lift check valve, and is a blind flange-shaped part. On the upper and lower edges, there are evenly distributed and through cylindrical holes for connecting the valve body 1 with the stud 3 and nut 4. In the middle of its lower surface, there is a protruding round table, and the center of the round table is a stepped blind hole for connecting the bushing 7, valve core 8 and compression spring 9. There is an exhaust hole on the conical surface of the round table communicating with the upper end of the stepped blind hole. A trapezoidal gasket ring groove is machined around the round table, and the gasket ring 5 shared with the valve body 1 is installed in the groove. The upper end of the valve core 8 is a smooth cylinder, inserted into the inner ring of the compression spring 9 and the blind hole under the valve cover 6 for guiding. The lower end of the valve core 8 is a combination of two positive and negative round tables with a first-level step, which is called the sealing end in the present invention. The function of the step is to prevent the compression spring 9 from shifting. The function of the positive round table is to facilitate the machining and installation of the small check valve. The function of the negative round table is to seal with the tapered hole of the valve seat 2. A dovetail groove is also machined on the conical surface of the negative round table, and an O-ring 11 is installed in the dovetail groove to enhance the sealing effect between the valve core 8 and the valve seat 2.

[0017] The small check valve of the present invention is composed of adding an external hexagonal hollow plug 10 and a small steel ball 12 with the sealing end of the lifting check valve spool 8 as the valve body. The external hexagonal hollow plug 10 has a flat hexagonal body and a relief groove at the outer end, a relatively long stud body at the inner end, and a through cylindrical hole in the center; symmetric drain grooves are cut on the inner end face of the external hexagonal hollow plug 10. The inlet of the small check valve is located at the center of the lower end face of the spool 8, and the outlet is located on the conical surface of the positive frustum of the spool 8. The inlet hole and the outlet hole intersect and communicate. From the outside to the inside, the inlet hole is successively a threaded hole, a relief groove, a chamfer, and an intersection hole; the filter screen 14 is installed in the relief groove and fixed with an internal hexagonal hollow plug 13; the size of the pores of the filter screen 14 can be determined according to the medium situation inside the valve and the aperture size of the small check valve; in the case of pure medium and a relatively large aperture of the small check valve, the internal hexagonal hollow plug 13, the filter screen 14, and their installation holes can be omitted to reduce costs. From the outside to the inside and with the diameter decreasing from large to small, the outlet hole is successively a countersunk hole, a threaded hole, a cylindrical hole, a conical hole, and an intersection hole; the small steel ball 12 is installed at the cylindrical hole and the conical hole for drain or sealing; the external hexagonal hollow plug 10 is installed at the countersunk hole and the threaded hole to prevent the small steel ball 12 from slipping out.

[0018] Figure 1 The overall structure shown is a preferred embodiment of the present invention, but not limited thereto. The axis angle α between the inlet hole and the outlet hole of the small check valve of the present invention is set between 45° and 90°. The change of the positive frustum shape of the sealing end of the spool 8 with the angle α has no obvious influence on the performance of the lifting check valve and the small check valve; in addition, any changes made to the structure and the shape of the components of the lifting check valve without departing from the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A lifting check valve capable of reducing the harm of water hammer, comprising a valve body, a valve seat, a valve cover, a bushing, a valve core, a compression spring and used seals and connectors. It is characterized in that: Inside the sealing end of the valve core of the lifting check valve, there is a small check valve sealed by small steel balls. The small check valve is composed of taking the sealing end of the valve core of the lifting check valve as the valve body and adding an external hexagonal hollow plug and small steel balls. The inlet of the small check valve is located at the center of the lower end face of the valve core, and the outlet is located on the conical surface of the positive frustum of the valve core. The inlet hole and the outlet hole communicate with each other; from the outside to the inside, the inlet hole is successively a threaded hole, a tool withdrawal groove, a chamfer and an intersection hole; from the outside to the inside and the diameter from large to small, the outlet hole is successively a counterbored hole, a threaded hole, a cylindrical hole, a tapered hole and an intersection hole; the small steel balls are installed at the cylindrical hole and the tapered hole for discharging or sealing; the external hexagonal hollow plug is installed at the counterbored hole and the threaded hole. The external hexagonal hollow plug has a flat hexagonal body and a tool withdrawal groove at the outer end, a relatively long stud body at the inner end, and a through cylindrical hole in the center; symmetric discharge grooves are cut on the inner end face of the external hexagonal hollow plug.

2. The lifting check valve capable of reducing the harm of water hammer according to claim 1. It is characterized in that: An internal hexagonal hollow plug and a filter screen are also installed at the inlet of the small check valve.

3. The lifting check valve capable of reducing the harm of water hammer according to claim 1. It is characterized in that: The axis included angle α between the inlet hole and the outlet hole of the small check valve is set between 45° and 90°.

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