CN106051171A - Pressure self-balanced type stop check valve - Google Patents

Abstract

The invention discloses a pressure self-balancing cut-off check valve, which comprises a valve body, a valve disc, a valve rod and a valve cover. The valve body is respectively provided with a liquid inlet hole and a liquid return hole, and a piston and a piston cylinder are arranged in the valve body. , the piston and the piston cylinder are both set on the valve stem, a balance chamber is formed between the piston and the piston cylinder, and the valve body is provided with a diversion channel leading from the liquid inlet hole to the balance chamber. The radial cross-sectional size of the balance chamber It is equal to the medium diameter of the sealing surface of the valve seat. When the medium enters the balance chamber along the diversion channel, the medium presses the piston downward, and the piston drives the valve stem to move downward, thereby exerting a downward pressing force on the valve disc. The pressing force is equal to the upward medium force on the bottom of the valve disc and cancels each other to realize the self-balancing pressure of the medium on the valve disc; the invention can automatically balance the medium pressure acting on the valve disc through the principle of pressure self-balancing , so as to fundamentally eliminate the influence of medium pressure on valve operating performance and sealing quality.

Description

A pressure self-balancing stop check valve

technical field

The invention relates to the technical field of valves, in particular to a pressure self-balancing cut-off check valve suitable for cutting off or checking flow medium pipelines in high-pressure and large-diameter environments.

Background technique

Globe check valve refers to a valve in which the valve disc moves along the centerline of the valve seat, and the valve stem and the valve disc are not fixedly connected. It has the functions of stop valve and check valve. When the valve stem is lowered and the disc is pressed tightly on the valve seat, it acts as a stop valve; when the valve stem rises, it acts as a check valve.

Due to its small friction between sealing surfaces during opening and closing, long life, small opening height, low manufacturing cost, and convenient maintenance, it is widely used in petrochemical, shipbuilding, power station, metallurgy and other fields. Since the existing stop check valve technology products mainly include valve body, valve disc, valve stem, valve cover, etc., when the stop check valve with this structure closes the valve, the valve is closed due to the influence of the valve disc under the influence of the inlet pressure of the valve body. difficulty. The degree of difficulty increases with the increase of the medium pressure in the pipeline and the increase of the valve diameter. It seriously affects the sealing performance and operability of the valve, and also restricts the application of the stop check valve in high-pressure and large-diameter pipelines.

Contents of the invention

The purpose of the present invention is to provide a pressure self-balancing stop check valve with strong operability and reliable sealing, so as to meet the use requirements of stop check valves for high pressure and large diameter flow medium pipelines.

In order to achieve the above object, the technical solution adopted in the present invention is: a pressure self-balancing stop check valve, including a valve body, a valve disc, a valve stem and a valve cover. Inlet hole and liquid return hole, the valve cover is detachably set on the upper end surface of the valve body, one end of the valve stem passes through the valve cover and is connected with the valve disc, the valve disc is set in the cavity of the valve body and can be moved up and down with the valve stem Reciprocating motion to control the opening and closing of the liquid inlet, and a sealing pair is formed between the valve seat and the valve disc set in the inner cavity of the valve body;

The valve body is provided with a piston and a piston cylinder, both of which are sleeved on the valve stem, and the side end surface of the piston cylinder is fixedly connected with the valve body, and a sliding fit is formed between the piston cylinder and the valve stem, and the piston is located in the piston cylinder And can reciprocate up and down along the inner wall of the piston cylinder;

A balance chamber is formed between the piston and the piston cylinder, and the valve body is provided with a diversion channel leading to the liquid inlet hole to the balance chamber. The radial section size of the balance chamber is equal to the middle diameter of the sealing surface of the valve seat. When the medium enters the balance chamber along the diversion channel, the medium squeezes the piston downward, and the piston drives the valve stem to move downward to exert a downward pressing force on the valve disc, which is the same as the upward pressure on the bottom of the valve disc. The medium forces are equal in magnitude and cancel each other out to realize the self-balancing pressure of the medium on the disc.

As a further improvement, a through hole is opened on the piston cylinder, one end of the through hole communicates with the balance chamber, and the other end of the through hole communicates with the flow guiding channel.

As a further improvement, an annular groove is formed on the valve body at the position connecting the through hole and the flow guiding channel, and the apertures of the annular groove and the through hole are larger than the hole diameter of the flow guiding channel.

As a further improvement, the through holes are a plurality of small round holes uniformly arranged on the side of the piston cylinder, and the plurality of small round holes and the guide channel are used to introduce the medium into the balance chamber.

As a further improvement, a leak detection groove for leak detection is provided at the joint surface of the piston cylinder and the valve cover.

As a further improvement, the upper end surface of the piston cylinder closely fits with the valve cover.

As a further improvement, sealing rings are provided between the piston cylinder, the piston, the valve body and the valve rod.

As a further improvement, a sealing ring is provided between the valve stem and the piston.

As a further improvement, a clearance fit is used between the valve flap and the valve stem.

As a further improvement, a clearance fit is used between the valve stem and the piston.

Compared with prior art, the beneficial effect of the present invention is:

1. The pressure self-balancing stop check valve of the present invention can automatically balance the medium pressure acting on the disc through the pressure self-balancing principle, thereby fundamentally eliminating the influence of the medium pressure on the valve's operating performance and sealing quality;

2. The pressure self-balancing stop check valve of the present invention has the characteristics of compact structure, small opening and closing torque, strong operability, and reliable sealing, and meets the use requirements of stop check valves for high-pressure and large-diameter flow medium pipelines.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Marks in the figure: 1, valve body, 101, liquid inlet hole, 102, valve seat, 103, liquid return hole, 104, diversion channel, 105, annular groove, 2, valve disc, 3, valve stem, 4, piston , 5, piston cylinder, 6, valve cover, 7, fasteners, 8, sealing ring.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a pressure self-balancing cut-off check valve includes a valve body 1, a valve disc 2, a valve stem 3 and a valve cover 6, and the valve body 1 is respectively provided with liquid inlet holes communicating with its chamber. 101 and liquid return hole 103, the valve cover 6 is detachably arranged on the upper end surface of the valve body 1 through the fastener 7, one end of the valve stem 3 passes through the valve cover 6 and is connected to the valve disc 2, and the valve stem 3 and the valve disc 2 adopt clearance fit, the valve disc 2 is set in the chamber of the valve body and can reciprocate up and down with the valve stem 3 to control the opening and closing of the liquid inlet, the valve seat 102 set in the inner cavity of the valve body 1 and the valve disc 2 A sealed pair is formed between them.

The valve body 1 is provided with a piston 4 and a piston cylinder 5, the piston 4 and the piston cylinder 5 are both sleeved on the valve stem 3, the side end surface of the piston cylinder 5 is fixedly connected with the valve body 1, and the upper end surface of the piston cylinder 5 is connected to the valve cover. 6 close fit, a sliding fit is formed between the piston cylinder 5 and the valve rod 3, the piston 4 is located in the piston cylinder 5 and can reciprocate up and down along the inner wall of the piston cylinder 5.

A balance chamber is formed between the piston 4 and the piston cylinder 5. The balance chamber is the cavity surrounded by the piston 4 and the piston cylinder 5. The valve body 1 is provided with a flow guide channel 104 leading to the liquid inlet hole to the balance chamber. The radial cross-sectional size of the balance chamber is equal to the middle diameter of the valve seat sealing surface. The middle diameter of the valve seat sealing surface is the average value of the outer diameter and inner diameter of the valve seat sealing surface. In the internal state, the medium presses the piston 4 downward, and the piston 4 drives the valve stem 3 to move downward to exert a downward pressing force on the valve disc 2, which is the same as the upward medium force on the bottom of the valve disc 2. A pair of axial forces of equal size and offsetting each other are formed, and the pressure self-balancing of the medium on the disc 2 is realized.

A through hole is opened on the piston cylinder 5 , one end of the through hole communicates with the balance cavity, and the other end of the through hole communicates with the diversion channel 104 .

An annular groove 105 is formed on the valve body 1 at the position connecting the through hole and the flow guiding channel 104 , and the diameters of the annular groove 105 and the through hole are larger than that of the flow guiding channel 104 . The annular groove 105 is convenient for the medium to be smoothly introduced into the balance chamber.

As a further improvement, the through holes may also be a plurality of small round holes uniformly arranged on the side of the piston cylinder 5, and the plurality of small round holes and the guide channel 104 are used to smoothly introduce the medium into the balance chamber.

A leak detection groove for checking whether the medium leaks is provided at the joint surface of the piston cylinder 5 and the valve cover 4 .

A sealing ring 8 is arranged between the piston cylinder 5 and the piston 4 , the valve body 1 and the valve stem 3 , and a sealing ring 8 is arranged between the valve stem 3 and the piston 4 .

The valve stem 3 and the piston 4 adopt clearance fit.

There is a spherical contact between the head of the valve stem 3 and the disc 2 .

The valve clack of the invention adopts a streamlined structure design, which is beneficial to reduce the flow resistance coefficient of the valve.

The valve body 1 can adopt a straight-through or angled structure. The diversion channel 104 is machined and formed on the valve body, and the ports of the diversion channel are sealed and welded after machining.

The pressure self-balancing cut-off check valve of the present invention can be opened and closed by rotating lift or vertical lift.

The working principle of pressure self-balancing of the present invention is as follows:

When the medium pressure comes from the liquid inlet hole 101, the medium pressure is introduced into the balance chamber through the guide channel 104 on the valve body 1, the piston 4 is subjected to the downward force of the medium, and the valve disc 2 is subjected to the downward pressing force of the piston 4 and the valve The upward medium force on the bottom of the flap 2 forms a pair of axial forces of equal size and offset each other, which realizes the self-balancing of the pressure of the medium on the valve flap 2. Therefore, the present invention can realize the pressure self-balancing of the valve. The invention saves labor in the process of closing the valve.

When the valve is opened and closed, the piston 4 reciprocates in the piston cylinder 5, and the middle is sealed by the sealing ring 8; the piston cylinder 5 is fixed between the valve body 1 and the valve cover 6, and the piston cylinder 5 and the valve body 1 are sealed by the sealing ring 8 ; The valve body 1 and the bonnet 6 are flanged and fixed by fasteners 7 . When the valve is closed, the hand wheel or actuator drives the valve stem 3 to move downward, and the valve stem 3 transmits the force to the valve disc 2 to complete the closing action of the valve; when the valve is opened, the valve stem 3 is driven upward by the hand wheel or actuator Movement, under the action of the medium force, the valve disc 2 moves upward along the valve stem 3, thereby realizing the valve opening action.

Claims (10)

1. a pressure self-balancing formula screw down nonreturn valve, including valve body, flap, valve rod and valve gap, valve body is respectively equipped with and it Inlet opening that chamber is interconnected and hole for back flow, on the detachable upper surface being arranged on valve body of valve gap, valve rod one end passes valve It is connected with flap after lid, in flap is located at the chamber of valve body and can pump to control with valve rod the keying of liquid feeding end, A sealing pair is constituted between the valve seat and the flap that arrange in the inner chamber of valve body, it is characterised in that:

It is provided with piston and piston cylinder, piston and piston cylinder in described valve body to be all set on valve rod, the side end face of piston cylinder and valve Body is fixing to be connected, and constitutes and be slidably matched between piston cylinder and valve rod, and piston is positioned at piston cylinder can be upper and lower along piston cylinder inwall Move back and forth；

Form a counter balance pocket between described piston and piston cylinder, valve body offers conducting inlet opening logical to the water conservancy diversion of this counter balance pocket Road, the radial section size of counter balance pocket is equal sized with sealing surface of seat central diameter, enters in counter balance pocket along flow-guiding channel at medium State under, medium is pressed down against piston, and piston driving valve rod moves downward thus grants the thrust that flap one is downward, this pressure The medium power upwards being subject to bottom clamp force and flap is equal in magnitude and cancels out each other, it is achieved medium to the pressure of flap from flat Weighing apparatus.

A kind of pressure self-balancing formula screw down nonreturn valve the most according to claim 1, it is characterised in that: open on described piston cylinder Being provided with through hole, one end of through hole connects with counter balance pocket, and the other end of through hole connects with flow-guiding channel.

A kind of pressure self-balancing formula screw down nonreturn valve the most according to claim 2, it is characterised in that: even on described valve body Connect the position of hole and flow-guiding channel to offer the aperture of cannelure, cannelure and through hole and be all higher than the aperture of flow-guiding channel.

4. according to a kind of pressure self-balancing formula screw down nonreturn valve described in Claims 2 or 3, it is characterised in that: described through hole For the uniform multiple small sircle holes being arranged on piston cylinder side, multiple small sircle holes and flow-guiding channel are for introducing counter balance pocket by medium In.

A kind of pressure self-balancing formula screw down nonreturn valve the most according to claim 4, it is characterised in that: described piston cylinder and valve It is provided with the leak detection groove for checking leakage at the faying face of lid.

6. according to a kind of pressure self-balancing formula screw down nonreturn valve described in claim 3 or 5, it is characterised in that: described piston cylinder Upper surface closely cooperate with valve gap.

A kind of pressure self-balancing formula screw down nonreturn valve the most according to claim 6, it is characterised in that: described piston cylinder and work It is equipped with sealing ring between plug, valve body, valve rod.

8. according to a kind of pressure self-balancing formula screw down nonreturn valve described in claim 5 or 7, it is characterised in that: described valve rod with Sealing ring it is provided with between piston.

A kind of pressure self-balancing formula screw down nonreturn valve the most according to claim 8, it is characterised in that: described flap and valve rod Between use matched in clearance.

10. according to a kind of pressure self-balancing formula screw down nonreturn valve described in claim 7 or 9, it is characterised in that: described valve rod with Matched in clearance is used between piston.