Balanced stop valve

Abstract

The utility model relates to a balance type stop valve which comprises a valve seat, a valve sleeve, a piston, a check ring, an O-shaped ring and a valve rod, the valve sleeve is connected to the valve seat, and the piston and the valve rod are connected in the valve sleeve in a matched mode. A balance hole is formed in the valve rod and penetrates through the bottom of the valve rod and the side face through hole in the upper portion. The balance type stop valve is small in opening and closing load; the valve disc moves linearly, so that the action reliability is high; high pressure difference can be borne; the sealing is reliable, and bidirectional sealing can be realized; the opening is quick; the structure is simple and reliability is good.

Description

TECHNICAL FIELD

[0001] The utility model relates to a stop valve, concretely relates to a balanced stop valve. BACKGROUND

[0002] Whether the stop valve can be effectively sealed depends on the pressure on the unit area of the sealing surface, that is, the specific pressure, and the pressure is related to multiple factors. Generally speaking, the specific pressure necessary for the sealing of the closing element of the closed valve mainly depends on the width, material and medium working pressure of the sealing surface, and the actual operation of the sealing surface specific pressure is also related to the sealing surface form, temperature, machining accuracy, valve stem handle tightening torque and other factors. If the specific pressure of the sealing surface is too small, the sealing cannot be guaranteed; if the specific pressure of the sealing surface is too large, the sealing pair may be damaged, resulting in sealing failure.

[0003] At present, the research on the sealing performance of the stop valve mainly focuses on simple changes to the stop valve disc structure, sealing form, and sealing surface material, but there are still problems such as large opening and closing torque and difficulty in achieving rapid opening and closing. In order to achieve automatic rapid opening and closing control, the electric stop valve can be driven by a motor. However, the traditional electric stop valve mostly adopts the form of a servo motor plus a speed reducer, greatly increasing the volume and weight of the stop valve. At the same time, due to the increase of the mechanical structure, the reliability and maintenance difficulty of the stop valve are increased, and it is difficult to achieve precise control, increasing the possibility of sealing failure. SUMMARY

[0004] The utility model provides a balanced stop valve, the stop valve opening and closing load is small, the valve disc movement is linear motion, the action reliability is high, can bear high pressure difference, the sealing is reliable, and two-way sealing can be realized, the opening is rapid, the structure is simple, and the reliability is good.

[0005] To achieve the above object, the technical scheme of the utility model is as follows: a balanced stop valve, comprising a valve seat, a valve sleeve, a piston, a stop ring, an O-shaped ring and a valve stem, the valve seat is connected with the valve sleeve, and the piston and the valve stem are connected with the valve sleeve in the valve sleeve; the valve stem is provided with a balance hole, and the balance hole penetrates through the bottom and the upper side hole of the valve stem.

[0006] Further, the piston and the valve sleeve are sealed and connected by the stop ring and the O-shaped ring; the piston and the valve stem are sealed and connected by the stop ring and the O-shaped ring; the valve stem and the valve sleeve are sealed and connected by the stop ring and the O-shaped ring.

[0007] Further, the piston connected in the valve sleeve divides the valve sleeve into the B cavity and the C cavity, and the A cavity is formed between the valve seat and the bottom of the valve stem.

[0008] Further, when the medium enters the valve body from the inlet end, the medium enters the C cavity at the upper end of the valve stem from the balance hole at the low end of the valve stem to generate a downward force, and finally the medium acts on the upper and lower ends of the valve stem in the downward direction, so that the valve stem and the valve seat are reliably sealed.

[0009] Compared with the prior art, the balance type stop valve has the advantages that:

[0010] The balance type stop valve has small opening and closing load, linear movement of the valve disc, high action reliability, high pressure difference resistance, reliable sealing, bidirectional sealing, rapid opening, simple structure and good reliability. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a whole structure schematic view of the balance type stop valve. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical scheme and advantages of the balance type stop valve clearer and more understandable, the balance type stop valve will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the balance type stop valve and are not used to limit the balance type stop valve, that is, the described embodiments are only a part of the embodiments of the balance type stop valve, but not all the embodiments. The components of the balance type stop valve embodiments described and shown in the drawings herein can be arranged and designed in various different configurations.

[0013] Therefore, the detailed description of the embodiments of the balance type stop valve provided in the drawings below is not intended to limit the scope of the claimed balance type stop valve, but only represents selected embodiments of the balance type stop valve. Based on the embodiments of the balance type stop valve, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the balance type stop valve.

[0014] As Figure 1 shown, the balance type stop valve comprises a valve seat 1, a valve sleeve 2, a piston 3, a check ring 4, an O-shaped ring 5 and a valve rod 6. The valve sleeve 2 is connected to the upper surface of the valve seat 1, and the piston 3 and the valve rod 6 are connected to the valve sleeve 2.

[0015] The piston 3 connected to the valve sleeve 2 divides the valve sleeve 2 into a B cavity in the upper part and a C cavity in the upper part, and an A cavity is formed between the valve seat 1 and the bottom of the valve rod 6.

[0016] The valve rod 6 is provided with a balance hole 7, and the balance hole 7 penetrates the bottom and the upper side surface of the valve rod 6.

[0017] The piston 3 and the valve sleeve 2 are sealingly connected through the check ring 4 and the O-shaped ring 5; the piston 3 and the valve rod 6 are sealingly connected through the check ring 4 and the O-shaped ring 5; and the valve rod 6 and the valve sleeve 2 are sealingly connected through the check ring 4 and the O-shaped ring 5.

[0018] When the medium enters the valve body 1 from the inlet end, it enters the C chamber at the upper end of the valve stem 3 through the balance hole at the lower end of the valve stem 3, so as to generate a downward acting force. Finally, the resultant force acting on the upper and lower ends of the valve stem 3 is downward, ensuring reliable sealing between the valve stem 3 and the valve seat 2.

[0019] The working principle of the balanced globe valve of the present utility model:

[0020] When the balanced globe valve is in the closed state and the pressure medium (pressure PA) enters from the A chamber (inlet end), the medium enters the C chamber through the balance hole on the valve stem 6. The pressure at the outlet end is PB. The finally formed resultant force F_total is:

[0021] F_total = PA × (SA - SC) + PB × SB (N)

[0022] In the formula, SA, SB, and SC are the areas of the A chamber, B chamber, and C chamber respectively. Since SA > SC, so F_total1 is conducive to forming a seal between the valve stem and the valve seat.

[0023] The specific pressure q generated by the resultant force on the sealing surface = F_total / SA,

[0024] The specific pressure generated by the resultant force on the sealing surface:

[0025] F_total1 = PA × (SA - SC) + PB × SB = 159.4PA + 176.71PB (N)

[0026] q = F_total / SA = 1.32~2.29PA (MPa)

[0027] It can be seen that the resultant force of the medium acting force can promote the sealing of the valve port, and the higher the P value, the greater the specific pressure generated, which is more conducive to the sealing of the valve port.

[0028] According to the general design experience of the globe valve sealing specific pressure, the minimum specific pressure required for its sealing needs to reach 1.5~2.5 times the working pressure. Therefore, the sealing driving force F_drive1 of the actual valve stem can be greatly reduced (F_drive1 << F_total) (F_drive1 ≈ 0~142.5PA (N)).

[0029] Preferably, when the globe valve is opened instantaneously from the closed state, its acting force F_total2 = PA × (SA - SC) + PB × SB = 159.4PA + 176.71PB (N). F_total2 drives the valve stem to close downward. Therefore, the driving force of the valve stem needs to overcome F_total2 to make the valve stem disengage from the valve seat.

[0030] Preferably, after the globe valve is in the open state and continues to open, when the pressure medium (pressure P) enters from the A chamber (inlet end), at this time, the A chamber and the B chamber are connected, and the medium enters the C chamber through the balance hole on the valve stem 6. The finally formed resultant force F_total3 is:

[0031] Ftotal3 = PA x (SAB - SC) = 153.9 PA (N)

[0032] The direction of the total force is that the valve stem moves away from the valve seat, i.e. to promote the opening of the valve. The actual driving force Fdrive3 of the valve stem can be close to 0.

[0033] Preferably, the stop valve is closed in the open state, and the acting force is Ftotal4 = PA x (SAB - SC) = 153.9 PA (N) (the specific pressure is about 1.32 PA). Ftotal4 drives the valve stem to move upward, therefore, the driving force Fdrive4 of the valve stem needs to overcome Ftotal4 to make the valve stem close to the valve seat (Fdrive4 ≈ 20.9-137.58 PA (N)).

[0034] In summary: the maximum driving force required by the valve stem is:

[0035] Fdrive2 = 159.4 PA + 176.71 PB (N)

[0036] In the description of the utility model, it should be explained that, unless otherwise explicitly provided and limited, the terms "mounting", "connecting", "connection" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0037] The above content is only an example and description of the structure of the utility model, and those skilled in the art can make various modifications or supplements or adopt similar ways to replace the described specific embodiments, as long as they do not deviate from the structure of the utility model or exceed the scope defined by the present claims, which shall belong to the protection scope of the utility model.

Claims

1. A balanced stop valve, characterized by: The valve seat, the valve sleeve, the piston, the stop ring, the O-shaped ring and the valve rod are included, the valve seat is connected with the valve sleeve, the piston and the valve rod are connected with the valve sleeve in cooperation, the balance hole is arranged in the valve rod, the balance hole penetrates the bottom and the upper side hole of the valve rod, the piston and the valve sleeve are sealed and connected through the stop ring and the O-shaped ring, the piston and the valve rod are sealed and connected through the stop ring and the O-shaped ring, and the valve rod and the valve sleeve are sealed and connected through the stop ring and the O-shaped ring.

2. Balanced cut-off valve according to claim 1, characterized in that The piston connected with the valve sleeve divides the valve sleeve into the B cavity and the C cavity, and the A cavity is formed between the valve seat and the bottom of the valve rod.

3. Balanced stop valve according to claim 2, characterized in that: When the medium enters the valve body from the inlet end, the medium enters the C cavity at the upper end of the valve rod from the balance hole at the low end of the valve rod, so as to generate the downward force, and finally the resultant force of the medium acting on the upper and lower ends of the valve rod is downward, so that the valve rod and the valve seat are reliably sealed.

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