CN114321392A - A two-way high temperature and high pressure self-balancing shut-off valve - Google Patents

Abstract

The invention discloses a two-way high temperature and high pressure self-balancing cut-off valve, which comprises a valve body, a valve cover, a valve disc and a valve stem; a balance hole is arranged on the valve disc or the valve stem; A composite sealing ring; the composite sealing ring sequentially includes an upper gasket, an upper sealing ring, an upper sub-ring, a lower sub-ring and a lower sealing ring from top to bottom, and a blocking ring is sleeved on the outer side of the upper washer. The invention has a two-way pressure self-balancing and two-way self-sealing structure, which greatly reduces the operating force of the opening and closing valve. Reliable sealing, long service life and simple manufacturing method, suitable for various pressure pipelines with bidirectional or unidirectional flow; at the same time, the seals are made of high temperature and corrosion resistant materials, especially for large diameter and high temperature in power, petrochemical and other industries , high pressure pipeline.

Description

A two-way high temperature and high pressure self-balancing shut-off valve

technical field

The invention relates to a valve, in particular to a bidirectional high temperature and high pressure self-balancing shut-off valve used for cutting off or connecting a bidirectional flow medium pipeline under high temperature, high pressure or corrosive environment.

Background technique

Valves are an indispensable and important mechanical product on pressure pipelines and are widely used in petrochemical, oilfield, metallurgy, thermal power, nuclear power and ships and other fields. During the use of existing valve products, the valve needs to overcome the medium pressure on the opening and closing parts to open and close the valve. When the valve is used for high temperature, high pressure and large diameter pipelines, an external bypass auxiliary valve must be additionally configured to relieve pressure. To open and close, the medium pressure not only makes the valve operation very difficult, but also easily causes damage and leakage of the valve sealing surface.

The pressure self-balancing valve can self-balance the medium pressure acting on the opening and closing parts through the principle of pressure self-balancing, and fundamentally eliminate the influence of the medium pressure on the valve operation performance, sealing quality and sealing life. The pressure self-balancing valve is an important way to transform and upgrade the existing valve products, and the key technology to realize the pressure self-balancing globe valve is the sealing of the pressure self-balancing structure. In the prior art, "O" type, "Y" type and other sealing rings are usually used to seal the pressure self-balancing structure. Since this type of sealing technology can convert the medium pressure into the pressure self-sealing of the sealing ring to the medium, the sealing ring does not need to be sealed. A very large sealing pre-tightening force can obtain a very good sealing effect, and during the use of the sealing ring, the sealing effect of the sealing ring is not only independent of the medium pressure, but also does not decrease with the sealing pre-tightening force after the sealing ring is worn. change, so it has a durable and reliable seal quality and seal life. However, in practical applications, there are a large number of high-temperature and high-pressure pipelines with bidirectional flow in the pipeline systems of petrochemicals, oil fields, metallurgy or power plants. When the water supply is stopped, the valve needs to be opened to make the water supply pipeline unobstructed, and when the water pump stops water supply, the valve needs to be closed to prevent the backflow of the supplied high-pressure water. The valve is sent into the common main pipe. When the gas supply of part of the boiler is stopped, the valve also needs to be closed to prevent the backflow of high temperature and high pressure steam. Since the high-density elastic materials that can be used to make "O", "Y" and other sealing rings are all rubber and plastic that are not resistant to high temperature, the existing pressure self-balancing globe valve is only suitable for media below 200 °C environment, it cannot be used for high-temperature pressure pipelines with a wide range of areas such as steam.

In order to solve the above problems, the invention patent application submitted by the inventor in 2018 (the application number is 201810862132.3) provides a two-way pressure self-balancing stop valve, a composite sealing ring is arranged on the valve disc, and the composite sealing ring includes pressure Ring, blocking ring, upper gasket, upper seal, upper spacer, lower spacer and lower seal. The shapes of the lower end face of the pressure ring and the upper end face of the upper gasket are the conical, inclined, flat or spherical surfaces that extrude the blocking ring toward the inner direction of the valve disc, and the shapes of the lower end face of the upper gasket and the upper end face of the upper spacer ring are Extrude the conical surface, inclined surface or spherical surface of the upper sealing ring to the outer direction of the valve disc, and the shape of the lower end surface of the lower spacer ring and the upper end surface of the valve disc is to extrude the conical surface, inclined surface or spherical surface of the lower sealing ring to the outer direction of the valve disc However, the structure of the above-mentioned valve is relatively complicated, especially the blocking ring is arranged on the upper gasket, and the upper gasket is arranged on the elastic sealing ring. The upper gasket will slide down along the sealing ring, making it difficult for the pressing force exerted by the pressure ring to effectively act on the blocking ring, so it is difficult to obtain sufficient Large sealing blocking force, so it is not only difficult to assemble, but also directly affects the sealing effect of high-pressure media.

SUMMARY OF THE INVENTION

Purpose of the Invention: The purpose of the present invention is to provide a shut-off valve installed on a medium bidirectional flow pipeline in a high temperature, high pressure or corrosive environment.

Technical solution: The two-way high temperature and high pressure self-balancing shut-off valve of the present invention includes a valve body, a valve cover, a valve stem and a valve disc. The valve body channel of the lower channel; also includes a composite sealing ring and a blocking ring. The composite sealing ring includes an upper gasket, an upper sealing ring, an upper sub-ring and a lower sub-ring that are sequentially sleeved outside the valve disc from the valve cover to the valve body direction. and the lower sealing ring, the blocking ring is sleeved outside the upper washer, and the valve disc or valve stem is provided with a balance hole which communicates the inner cavity of the valve disc and the upper cavity of the valve body.

The side end surface of the upper gasket is a conical surface, an inclined surface, a flat surface or a spherical surface that squeezes the blocking ring toward the valve body. Squeeze the conical surface, inclined surface or spherical surface of the upper sealing ring, and the shape of the lower end surface of the lower sub-ring and the upper end surface of the valve body is the conical surface, inclined surface or spherical surface of the lower sealing ring extruding toward the valve body.

The inner surface of the valve body is provided with an annular sealing ring accommodating groove and a blocking ring accommodating groove; the outer surface of the valve flap and the inner surface of the valve body are clearance fit with the upper gasket, the upper sub-ring and the lower sub-ring; the upper sub-ring There is a gap between the lower end face of the valve disc and the upper end face of the lower sub-ring; the lower end face of the valve flap and the channel in the valve body have a matching sealing surface, and the sealing surface is a plane, a conical surface or a spherical surface; between the upper gasket and the valve cover A pressing piece is installed, and the pressing piece is threadedly connected with the valve body; the blocking ring, the upper sealing ring and the lower sealing ring are made of flexible graphite or polytetrafluoroethylene.

Beneficial effects: Compared with the prior art, the present invention has the following advantages: a bidirectional pressure self-sealing structure is proposed, so that the sealing structure is composed of sealing rings made of materials with low density, high temperature resistance or corrosion resistance. The pressure self-sealing characteristics of the sealer also have lasting and reliable sealing quality and sealing life, simple assembly, high reliability, more reasonable force relationship between seals, and can be used in high temperature and high pressure or corrosive environments. The medium pressure on the disc is self-balanced, and the valve is easy to operate, which reduces the labor intensity of manual operation of manual valves and the energy consumption of electric and pneumatic valves. It is suitable for large-diameter and bidirectional medium flow pipelines, with good safety and scope of application. wide.

Description of drawings

1 is a schematic structural diagram of a preferred embodiment of the present invention;

Fig. 2 is the partial enlarged view of A place in Fig. 1;

3 is a schematic diagram of the extrusion force when the upper sealing ring is pre-tightened in the present invention;

4 is a schematic diagram of the extrusion force when the lower sealing ring is pre-tightened according to the present invention;

5 is a schematic diagram of the medium pressure self-sealing force of the upper sealing ring of the present invention;

FIG. 6 is a schematic diagram of the medium pressure self-sealing force of the lower sealing ring of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below with reference to the accompanying drawings.

As shown in FIG. 1 , the bidirectional high temperature and high pressure self-balancing shut-off valve of this embodiment includes a valve body 1, a valve disc 4, a valve cover 18, a valve stem 19, a pressing member 17, a blocking ring 13, and an upper gasket 15, an upper The sealing ring 11, the upper sub-ring 10, the lower sub-ring 9 and the lower sealing ring 7 are composite sealing rings, the upper washer 15 is provided with a blocking ring 13, and a pressing member 17 is installed between the upper washer and the valve cover.

The valve cover 18 is fixedly connected with the valve body 1, the valve stem 19 passes through the valve cover 18, and the lower end of the valve stem is connected with the valve disc 4 and can carry the valve disc 4 to move up and down along the inner surface of the valve body 1 to complete the opening or closing of the valve. closure.

The valve body 1 is provided with an upper channel 3, a lower channel 33 and an inner channel 35 connecting the upper channel 3 and the lower channel 33. The valve flap 4 is arranged in the cavity of the valve body 1, and the upper end surface of the inner channel 35 is connected to the valve flap. The lower end surface of 4 is provided with a sealing surface that cooperates with each other, and its shape is a plane, a conical surface or a spherical surface.

The valve flap 4 or the valve stem 19 is provided with a balance hole 21 for communicating with the lower channel 33 located below the lower end surface 34 of the valve flap 4 and the valve body upper cavity 16 located above the upper end surface 20 of the valve flap 4;

The inner surface of the valve body 1 is provided with an annular sealing ring accommodating groove and a blocking ring accommodating groove. The upper gasket 15, the upper sealing ring 11, the upper sub-ring 10, the lower sub-ring 9 and the lower sealing ring 7 are arranged from top to bottom In the sealing ring accommodating groove, the blocking ring is located in the blocking ring accommodating groove;

There is a gap between the lower end surface 26 of the upper sub-ring 10 and the upper end surface 27 of the lower sub-ring 9 . The outer circle 5 of the valve flap 4 is in clearance fit with the upper washer 15 , the upper sub-ring 10 , the lower sub-ring 9 and the inner circle of the valve body 1 ;

The blocking ring 13, the upper sealing ring 11 and the lower sealing ring 7 are made of sealing materials. In this embodiment, in order to achieve the purpose of high temperature resistance, the sealing material is flexible graphite. Sealing material.

The shape of the end surface 14 on the side of the upper gasket 15 is a conical surface, inclined surface, a flat surface or a spherical surface that presses the blocking ring 13 in the direction of the end surface 12 on the side of the valve body 1 . Press the blocking ring 13 in the direction of the side end face 12 of the valve body 1 to block the medium channel that continues to flow between the upper gasket 15 and the valve body 1 after the medium penetrates into the outer surface 23 of the upper sealing ring 11;

The shape of the lower end surface 22 of the upper gasket 15 and the upper end surface 25 of the upper sub-ring 10 is to squeeze the conical surface, inclined surface or spherical surface of the upper sealing ring 11 toward the inner direction of the valve body 1; 15 and the upper sub-ring 10 press the upper sealing ring 11 inward together, and obtain a larger sealing preload on the inner circular surface 24 of the upper sealing ring 11 than its outer circular surface 23, which is convenient for the medium to move along the lower and lower parts of the upper sub-ring 10. The gap between the end surface 26 and the upper end surface 27 of the lower sub-ring 9, and then along the gap between the outer circle of the upper sub-ring 10 and the inner cavity 8 of the valve body 1, squeeze into the outer surface of the upper sealing ring 11 with less pre-tightening force. 23, so as to squeeze the upper sealing ring 11 inward, forcing the inner circular surface 24 of the upper sealing ring 11 to be further close to the outer circle 5 of the valve flap 4, forming the pressure self-sealing of the upper sealing ring 11 to the valve flap 4, and the upper sealing ring The force situation during preloading is shown in Figure ₃ , where N1 and N1 _' represent the extrusion force in different directions, and _N2 represents the sealing preload;

Similarly, the shape of the lower end surface 28 of the lower sub-ring 9 and the upper end surface 31 of the valve body 1 is to squeeze the conical surface, inclined surface or spherical surface of the lower sealing ring 7 toward the inner direction of the valve body 1 . The sub-ring 9 and the valve body 1 press the lower sealing ring 7 inward together, and the inner circular surface 30 of the lower sealing ring 7 obtains a larger sealing pre-tightening force than its outer circular surface 29, which is convenient for the medium to move along the upper sub-ring 10. The gap between the end surface 26 and the upper end surface 27 of the lower sub-ring 9, and then along the gap between the outer circle of the lower sub-ring 9 and the inner cavity 8 of the valve body 1 penetrates into the outer surface of the lower sealing ring 7 with less preload 29, form the downward extrusion in the inner direction of the sealing ring 7, forcing the inner circular surface 30 of the lower sealing ring 7 to be further close to the outer circle 5 of the valve disc 4, forming the pressure self-sealing of the lower sealing ring 7 to the valve disc 4, and the lower sealing ring 7 is self-sealing. The stress condition of the sealing ring during pre-tightening is shown in Figure 4, where N ₁ and N ₁ ' represent the extrusion force in different directions, and N ₂ represents the sealing pre-tightening force;

There is a gap between the lower end surface 26 of the upper sub-ring 10 and the upper end surface 27 of the lower sub-ring 9. The purpose is to facilitate the upward extrusion of the medium along the lower end surface 26 of the upper sub-ring 10, forcing the upper sealing ring 11 and the upper gasket. 15. The lower end surface 22 of 15 is further attached to form the self-sealing pressure of the upper sealing ring 11 on the lower end surface 22 of the upper gasket 15; The upper end surface 31 is further in close contact, so that the pressure of the lower sealing ring 7 to the upper end surface 31 of the valve body 1 is self-sealing.

After the shut-off valve of the present invention is connected with the pressure pipeline, when the valve is in the closed state, if the medium enters from the lower channel 33, it will enter the upper cavity 16 of the valve body through the balance hole 21, so that the upper end face 20 and the lower end face 34 of the valve flap along the The axial direction of the valve disc 4 is subjected to a pair of opposite and mutually counteracting forces to realize the self-balance of the axial pressure of the medium along the valve disc 4; if the medium enters from the upper channel 3, the medium pressure acts on the outer surface 5 of the valve disc to form The radial forces that cancel each other realize the self-balance of the radial pressure of the medium along the outer circular surface 5 of the valve disc. When the present invention is in the open state, under the pulling of the valve stem 19, the valve flap 4 is lifted and the medium flows out through the valve body outlet along the valve body channel 35 until the valve is fully opened.

The valve disc is pushed down along the inner surface of the valve body by the valve stem 19, so that the second sealing surface on the lower end face 34 of the valve disc is in close contact with the sealing surface on the upper end surface of the channel 35 in the valve body to achieve sealing, and the valve is in the closed state at this time. , when the pressure medium enters from the upper channel 3 of the valve body, the self-sealing principle of the medium pressure is shown in Figure 5: where N ₃ and N ₃ ' represent the medium sticking force in different directions, N ₄ represents the medium pressure; the pressure medium passes through the valve The gap between the outer circle 5 of the flap and the inner circle 6 of the valve flows upward. Because the lower sealing ring 7 is subjected to the pre-tightening force, the pressure medium will squeeze through the inner surface 30 of the lower sealing ring 7, and then follow the outer circle 5 of the valve flap in turn. The gap with the inner circle of the lower sub-ring 9, the gap between the upper end surface 27 of the lower sub-ring 9 and the lower end surface 26 of the upper sub-ring 10, and the gap between the outer circle of the upper sub-ring 10 and the cavity 8 of the valve body flow into The outer surface 23 of the upper sealing ring 11 with smaller pre-tightening force, because the blocking ring 13 blocks the medium passage between the upper washer 15 and the valve body 1, the medium flowing into the lower end surface 26 of the upper sub-ring 10 flows along the upper The lower end surface 26 of the sub-ring 10 squeezes the upper sealing ring 11, so that the pressure of the upper sealing ring 11 to the lower end surface 22 of the upper gasket 15 is self-sealing, and the medium channel between the upper sealing ring 11 and the upper gasket 15 is blocked, so that the upper sealing ring 11 flows into the upper gasket 15. The medium on the outer circular surface 23 of the sealing ring 11 is formed to be squeezed in the inner direction of the upper sealing ring 11, forcing the inner circular surface 24 of the upper sealing ring 11 to be further close to the outer circle 5 of the valve disc 4, forming the upper sealing ring 11 to the valve disc 4. pressure self-sealing.

When the pressure medium enters from the lower channel 33 of the valve body, the self-sealing principle of the medium pressure is shown in Figure 6: N ₃ and N ₃ ' represent the medium contact force in different directions, N ₄ represents the medium pressure, and the pressure medium passes through the valve. The balance hole 21 set on the disc 4 or the valve stem 19 is transmitted to the upper cavity 16 of the valve body, and the pressure medium flows downward through the gap between the inner circle of the upper gasket 15 and the outer circle 5 of the valve disc. The pressure medium will squeeze through the inner circular surface 24 of the upper sealing ring 11, and then follow the gap between the outer circle 5 of the valve disc and the inner circle of the upper sub-ring 10 and the lower end surface 26 of the upper sub-ring 10 and the lower sub-ring. The gap between the upper end surface 27 of the lower sub-ring 9 and the gap between the outer circle of the lower sub-ring 9 and the cavity 8 of the valve body flows into the outer surface 29 of the lower sealing ring 7 with less pre-tightening force. The medium is pressed downward along the upper end surface 27 of the lower sub-ring 9, forming the pressure self-sealing of the lower sealing ring 7 to the upper end surface 31 of the valve body 1, blocking the lower sealing ring 7 and the upper end surface 31 of the valve body 1. The medium channel is formed, so that the medium flowing into the outer circular surface 29 of the lower sealing ring 7 is squeezed in the inner direction of the lower sealing ring 7, forcing the inner circular surface 30 of the lower sealing ring 7 and the outer circle 5 of the valve flap 4 to be further close, forming a The pressure of the lower sealing ring 7 to the valve disc 4 is self-sealing.

To sum up, since the pressing force of the extruded sealing ring is a self-sealing force formed by the medium pressure itself, it will become more reliable as the medium pressure increases, and its sealing effect is not only independent of the medium pressure, but also related to the above. The inner circular surface 24 of the sealing ring 11 or the inner circular surface 30 of the lower sealing ring 7 has nothing to do with the size of the sealing preload on the outer circle 5 of the valve disc 4. Therefore, the sealing ring can be made of a loose but high temperature resistant elastic material. The self-sealing of the medium pressure is realized, and at the same time, although the wear of the outer circular surface 5 of the valve disc 4 to the inner circular surface 24 of the upper sealing ring 11 or the inner circular surface 30 of the lower sealing ring 7 will lead to the decrease of the sealing pre-tightening force of the present invention, it is It will not lead to a decrease in the sealing effect of the present invention. In the present invention, the sealing is not achieved only by pressing between the parts and the sealing member, but by tightening the pressing member 17, the sealing member can obtain sufficient material density, and the inner circular surface 24 of the upper sealing ring 11 and the inner circular surface 24 and The inner circular surface 30 of the lower sealing ring 7 and the outer circular surface 5 of the valve disc 4 form a sealing pre-tightening force far less than the medium pressure, so that lasting and reliable sealing quality and sealing life can be obtained.

The test results of the shut-off valve of the present invention under the conditions that the valve diameter is 250mm, the sealing test pressure ≥42MPa, and the duration ≥60s show that the present invention achieves zero leakage, and the required operating torque of the valve is less than 450N·m, which is only 1/20 of the valve of the traditional technology, therefore, the present invention has excellent sealing performance and small operating torque, and is suitable for large-diameter pipes.

The above are only the preferred embodiments of the present invention. For those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention. The combination of the individual parts, the upper gasket, the pressing part and the valve cover can be made into one part, etc., the number and combination of the sealing parts can also be various, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (8)

1. A two-way high temperature and high pressure self-balancing shut-off valve, comprising a valve body (1), a valve cover (18), a valve stem (19) and a valve disc (4), and the valve body is provided with a valve body upper channel (3) , the lower channel (33) of the valve body and the inner valve channel (35) connecting the upper channel (3) of the valve body and the lower channel (33) of the valve body; a composite seal is provided between the valve body (1) and the valve disc (4) A ring and a blocking ring (13); characterized in that the composite sealing ring comprises an upper gasket (15), an upper sealing ring (11), an upper sub-ring which are sequentially sleeved on the outside of the valve flap from the valve cover to the valve body direction (10), a lower sub-ring (9) and a lower sealing ring (7), the blocking ring (13) is sleeved outside the upper washer (15); the valve disc (4) or the valve stem (19) is on the A balance hole (21) communicating with the inner cavity (36) of the valve disc and the upper cavity (16) of the valve body is opened. 2. The two-way high temperature and high pressure self-balancing shut-off valve according to claim 1, characterized in that, the side end surface (14) of the upper gasket (15) is a blocking ring (13) extruded in the direction of the valve body (1). The shape of the lower end surface (22) of the upper gasket (15) and the upper end surface (25) of the upper sub-ring (10) is to squeeze inward of the valve body (1) Press the conical surface, inclined surface or spherical surface of the sealing ring (11), and the shape of the lower end surface (28) of the lower sub-ring (9) and the upper end surface (31) of the valve body (1) is in the direction of the valve body Squeeze the conical, inclined or spherical surface of the lower sealing ring (7). 3 . The bidirectional high temperature and high pressure self-balancing shut-off valve according to claim 1 , wherein the inner surface of the valve body ( 1 ) is provided with annular sealing ring accommodating grooves and blocking ring accommodating grooves. 4 . 4. The bidirectional high temperature and high pressure self-balancing shut-off valve according to claim 1, characterized in that the outer surface of the valve flap (4) and the inner surface of the valve body are connected to the upper gasket (15), the upper sub-ring ( 10) Clearance fit of the lower sub-ring (9). 5. The bidirectional high temperature and high pressure self-balancing shut-off valve according to claim 1, characterized in that, between the lower end surface (26) of the upper sub-ring (10) and the upper end surface (27) of the lower sub-ring (9) with gaps. 6 . The two-way high temperature and high pressure self-balancing shut-off valve according to claim 1 , wherein the lower end surface of the valve flap ( 4 ) and the channel ( 35 ) in the valve body have a matching sealing surface, and the sealing surface is 6 . Flat, conical or spherical. 7. The two-way high temperature and high pressure self-balancing shut-off valve according to claim 1, wherein a pressing member (17) is installed between the upper gasket (15) and the valve cover (18), and the pressing member (17) is screwed to the valve body (1). 8. The bidirectional high temperature and high pressure self-balancing shut-off valve according to claim 1, wherein the blocking ring (13), the upper sealing ring (11) and the lower sealing ring (7) are made of flexible graphite or polytetrafluoroethylene Made of vinyl.

Images