WO2016041433A1

WO2016041433A1 - Metal bellow type pressure accumulator for shaft sealing system and centrifugal pump flushing system thereof

Info

Publication number: WO2016041433A1
Application number: PCT/CN2015/088221
Authority: WO
Inventors: 邢宇; 邢天宜
Original assignee: 邢宇
Priority date: 2014-09-15
Filing date: 2015-08-27
Publication date: 2016-03-24
Also published as: CN104791290A; CN104265700A

Abstract

Disclosed is a metal bellow type pressure accumulator for a shaft sealing system, wherein the pressure accumulator has a liquid inlet opening (5), a liquid outlet opening (6), a viewing window (4) and a liquid supplement opening (3) respectively formed on a side wall of a steel housing (2), an air charging opening (1) formed on a top end of the steel housing (2), and a liquid discharging opening (8) formed on a bottom end of the steel housing (2); a lower part of the steel housing (2) is provided with a cooling coiled pipe for cooling the liquid in the steel housing (2), a cooling water inlet opening (7) and a cooling water outlet opening (9) of the cooling coiled pipe are respectively located at a bottom end and an outer side of the steel housing (2); an inner part of the steel housing (2), via a flexible mechanism (10), is separated into an air cavity (11) on an upper part and a liquid cavity (12) on a lower part. The flexible mechanism (10) comprises a separating bottom plate (101) and a metal bellow (102), wherein the periphery of a bottom end opening of the metal bellow (102) is connected in a fixing and sealing manner on an upper end face of the separating bottom plate (101); and an upper end opening of the metal bellow (102) is connected in a fixing and sealing manner to a connection ring (103) which is formed integratedly on the periphery of the inner side wall of the upper end of the steel housing (2), and the connection ring (103) is located above the liquid supplement opening (3). Further disclosed is a centrifugal pump flushing system comprising the metal bellow type pressure accumulator. The system not only simplifies a standard and improves interchangeability, but also improves the reliability of the system and the security of the device operation.

Description

Metal bellows type accumulator for shaft sealing system and centrifugal pump flushing system thereof

Technical field

The invention relates to a flushing system for a centrifugal pump. In particular, it relates to a metal bellows type accumulator for a shaft sealing system and a centrifugal pump flushing system thereof.

Background technique

In the refining and chemical industry, centrifugal pumps and rotary pumps play an important role in mechanical equipment, and a complete shaft sealing system can ensure the safety of equipment operation. The standard mechanical seal flushing program and auxiliary metal components in the API682 standard are an important part of the shaft sealing system, and the accumulator is one of the most important of these auxiliary metal components. Accumulators are also important in machinery in the paper industry.

There are three types of accumulators used in the standard seal flushing plan 53A; the standard seal flushing plan 53B; and the standard seal flushing plan 53C in the API682 standard appendix D (standard appendix), respectively: 53A uses gas-liquid co-chamber accumulator The 53B uses a bile accumulator; the 53C uses a piston accumulator. These three accumulators have different deficiencies in their use in standard seal flushing programs. among them,

1. Standard sealed flushing plan 53A using gas-liquid same chamber accumulator

As shown in Figure 1 and Figure 2, in the API682 standard Appendix D (standard appendix), the accumulator used in the standard seal flushing plan 53A, the gas and liquid in the accumulator are always in the same room, so the gas It is easy to dissolve into the liquid, and the higher the pressure, the more gas is dissolved into the liquid, forming a liquid-liquid mixed phase liquid. This liquid flows into the mechanical seal chamber under the action of the mechanical seal pumping effect ring, and then enters the machine. Between the two end faces of the sealing friction pair, the lubricating film body between the friction pairs is destroyed, and even flashing and cavitation are caused, which greatly reduces the service life of the mechanical seal. The liquid in the accumulator is a barrier fluid, that is, its pressure must be greater than the pressure of the working medium. This pressure greatly increases the amount of gas dissolved in the liquid, which increases the damage of the mechanical seal.

2. Standard sealed flushing plan 53B using a bile accumulator

As shown in Figure 3 and Figure 4, in the API 682 standard Appendix D (standard appendix), the accumulator used in the standard seal flushing plan 53B uses a bile accumulator, and its gallbladder is in the shape of a hollow sphere. Made of rubber material, it is impossible to make a uniform wall thickness, and the density and elasticity of each place are not uniform and are not very regular spherical shapes. The outer ball blocks the liquid, and the inside of the ball is a high-pressure gas. In this way, the liquid and gas are separated. So it has the following disadvantages:

(1) It is not resistant to high temperature or low temperature, and the temperature range of the butadiene rubber is about -20-120 ° C; the temperature range of the fluororubber rubber is about 0-180 ° C;

(2) Other liquids with strong corrosiveness are mixed into the barrier liquid to corrode the inner tank;

(3) The barrier liquid is compatible with the material of the liner and is easy to swell;

(4) The telescopic frequency must not be too fast;

(5) low fatigue limit;

(6) The displacement direction is different when the position of the entire sphere is expanded and contracted, so there is no liquid level, so it is not easy to judge the amount of liquid in the accumulator;

(7) It can be seen from the standard seal flushing plan 53B of the API682 standard that the liquid in the accumulator does not participate in the blocking liquid. Cycle, which is quite unfavorable for this part of the liquid;

(8) The accumulator must be placed vertically, and cannot be placed horizontally or inverted. Otherwise, the inner tank will be in contact with the casing by the influence of buoyancy, which hinders the normal telescopic operation of the inner casing;

(9) It is not possible to use the internal cooler of the accumulator for cooling as in the standard seal flushing plan 53A, and an external cooler is required, which not only increases the cost but also has a complicated structure.

3. Standard sealed flushing plan 53C using piston accumulator

As shown in Fig. 5 and Fig. 6, the accumulator used in the standard seal flushing plan 53C in Appendix DD of the API 682 standard (standard appendix) is a piston accumulator, and the seal between the piston and the cylinder wall is relied on. Rubber O-rings are solved, so it has the following disadvantages:

(1). It is not resistant to high temperature or low temperature, and the temperature range of the butadiene rubber is about -20-120 degrees; the temperature range of the fluororubber rubber is about 0-180 degrees;

(2) Other liquids with strong corrosiveness are mixed into the corrosive rubber ring in the barrier liquid;

(3) The barrier liquid is compatible with the material of the rubber ring and is easy to swell;

(4) The rubber ring is rubbed against the inner wall of the accumulator to cause wear;

(5) It can be seen from the standard seal flushing plans 53B and 53C of the API682 standard that the liquid in the accumulator does not participate in the circulation of the barrier liquid, which is rather disadvantageous for this part of the liquid;

(6) It is not possible to use the cooler inside the accumulator itself for cooling as in the standard seal flushing plan 53A, and an external cooler is required, which is not only costly but also complicated in structure.

Summary of the invention

The technical problem to be solved by the present invention is to provide a metal bellows type accumulator for a shaft sealing system and a centrifugal pump flushing system capable of achieving liquid and gas isolation, gas not entering the liquid.

The technical solution adopted by the present invention is: a metal bellows type accumulator for a shaft sealing system, comprising a steel shell, respectively formed on the side wall of the steel shell, a liquid outlet, a window And a liquid filling port, an inflation port formed at a top end of the steel shell and a liquid discharge port formed at a bottom end of the steel shell, wherein a lower portion of the steel shell is provided with a cooling coil for cooling the liquid in the steel shell The cooling water inlet and the cooling water outlet of the cooling coil are respectively located outside the bottom end of the steel shell, and the inside of the steel shell is separated by an elastic mechanism into an upper air chamber and a lower liquid chamber.

The elastic mechanism comprises a separating bottom plate and a metal bellows, wherein the bottom port of the metal bellows is fixedly and sealingly connected to the upper end surface of the separating bottom plate, and the upper port of the metal bellows is fixed and sealed The ground connection is integrally formed on a connecting ring of one circumference of the inner side wall of the upper end of the steel shell, and the connecting ring is located above the liquid filling port.

The elastic mechanism constitutes an air cavity in an upper portion of the steel shell, and the air chamber communicates with an inflation port at the top end of the steel shell.

A liquid level sensor connected to the external monitoring system is disposed in the liquid chamber.

A centrifugal pump flushing system with a metal bellows type accumulator, comprising a centrifugal pump and a sealing gland connected to a pump shaft side of the centrifugal pump, the sealing gland being connected with a metal bellows type through a pipeline The accumulator, the metal bellows type accumulator comprises: a steel shell, a liquid inlet, a liquid outlet, a window and a liquid filling port respectively formed on the side wall of the steel shell, formed in the steel shell a top end of the gas inlet and a liquid discharge port formed at a bottom end of the steel shell, a lower portion of the steel shell is provided with a cooling coil for cooling the liquid in the steel shell, and the cooling coil of the cooling coil Import and cooling water outlets respectively On the outside of the bottom end of the steel shell, the inside of the steel shell is separated by an elastic mechanism into an air chamber at the upper portion and a liquid chamber at the lower portion.

The elastic mechanism includes a partition bottom plate and a metal bellows, and a bottom port of the metal bellows is fixedly and sealingly connected to an upper end surface of the partition plate, and an upper port of the metal bellows is fixedly and sealingly The connection is formed on a connecting ring formed on one of the inner side walls of the upper end of the steel casing.

A pressure sensor is disposed at the inflation port at the top of the steel shell.

The metal bellows type accumulator and the centrifugal pump flushing system thereof for the shaft sealing system of the invention have the following beneficial effects:

1. In the standard seal flushing plan 53A of the API682 standard, all the advantages are retained, and liquid and gas isolation can be achieved. Therefore, there is always a lubricating film body of the barrier fluid between the mechanical seal friction pairs to protect the mechanical seal from operating normally. .

2. Because there is no component made of rubber material in the metal bellows type accumulator, it can be used instead of the standard type flushing plan 53B in the API682 standard and the 53C middle piston accumulator can be large. The range is improved in resistance to low temperature and high temperature, and the working temperature can reach -100-400 °C.

3. Because there is no component made of rubber material in the metal bellows type accumulator, it can be used to replace the biliary accumulator in the standard seal flushing plan 53B and the piston accumulator in the 53C in the API682 standard. The range increases the corrosion resistance and the ability to resist swelling.

4. The expansion and contraction of the metal bellows is realized by displacement along a single axis. Therefore, the metal bellows accumulator is used instead of the standard seal flushing plan 53B in the API682 standard. The inner tank accumulator can be directly observed by using a window. The liquid level and the level sensor can also be arranged for remote control.

5. Use the metal bellows accumulator instead of the gas-liquid homogenous accumulator in the standard seal flushing plan 53A of the API682 standard and the standard seal flushing plan 53B in the API682 standard. The inner accumulator can be tilted or horizontally placed. It can even be inverted.

6. Especially when subjected to alternating load, the fatigue limit of the metal bellows is higher than the fatigue limit of the rubber parts, and it is used to replace the biliary accumulator in the standard seal flushing plan 53B of the API682 standard and the piston type accumulator in the 53C. The press can increase the fatigue life.

7. The metal bellows type accumulator can be equipped with a cooling coil like the gas-liquid same chamber accumulator in the standard seal flushing plan 53A of the API682 standard, and replace it with the standard seal flushing plan 53B in the API682 standard. The accumulator and the 53C piston accumulator eliminate the need for an external cooler, simplifying the system, saving space and saving costs.

8. The metal bellows accumulator can participate in the circulation of the barrier liquid like the liquid-liquid same chamber accumulator in the standard seal flushing plan 53A of the API682 standard, which is quite advantageous for ensuring the stability of the liquid property.

9. The telescopic frequency of the metal bellows is much faster than the telescopic frequency of the rubber liner, and it is much more sensitive than the inner wall of the rubber ring friction accumulator. Therefore, many misjudgments and misoperations can be avoided.

10. It is possible to add a spring inside the metal bellows type accumulator and pre-modulate the pressure difference between the liquid and the gas with a spring. How much pressure difference we want can be adjusted.

11. The outer dimensions of the metal bellows accumulator are made identical to the outer dimensions of the accumulators in the standard seal flushing plans 53A, 53B and 53C of the API682 standard.

12. The metal bellows accumulator not only retains all the advantages of the accumulators in the standard seal flushing plans 53A, 53B and 53C of the API682 standard and overcomes their disadvantages. That is to say, the metal bellows accumulator has the advantages.

13. Change the three types of accumulators used in the standard seal flushing plan 53A of the API682 standard appendix D (standard appendix); the standard seal flushing plan 53B; and the standard seal flushing plan 53C to a metal bellows accumulator In addition, the standard seal flushing plan 53A of the API682 standard appendix D (standard appendix); the standard seal flushing plan 53B; and the standard sealed flushing plan 53C three standard sealed flushing plans are combined into one type, namely: standard sealed flushing plan 53. This simplifies the standard and improves the interchangeability, while also improving the reliability of the system and the safety of the operation of the equipment.

DRAWINGS

1 is a schematic structural view of a prior art gas-liquid co-compartment accumulator;

2 is a schematic structural view of a centrifugal pump flushing system having a gas-liquid homogenous accumulator standard seal flushing plan 53A;

Figure 3 is a schematic structural view of a prior art inner tank accumulator;

Figure 4 is a schematic view showing the structure of a centrifugal pump flushing system having a liner-type accumulator standard seal flushing plan 53B;

Figure 5 is a schematic structural view of a prior art piston accumulator;

Figure 6 is a schematic view showing the structure of a centrifugal pump flushing system having a piston type accumulator standard seal flushing plan 53C;

Figure 7 is a schematic view showing the structure of a metal bellows type accumulator for a shaft sealing system of the present invention;

Figure 8 is a schematic view showing the structure of a centrifugal pump flushing system of the present invention having a metal bellows type accumulator for a shaft sealing system;

Figure 9 is an internal cross-sectional view of the sealed chamber of Figure 8.

In the picture

1: Inflatable port 2: Steel shell

3: refill port 4: window

5: inlet port 6: outlet port

7: Cooling water inlet 8: Discharge port

9: cooling water outlet 10: elastic mechanism

11: air cavity 12: liquid cavity

21: Working medium hydraulic pressure introduction port 22: working fluid medium chamber

23: Sealing liquid chamber 24: Barrier pressure inlet

25: Piston 26: Rubber seal

27: Steel shell 101: Separate bottom plate

102: metal bellows 103: connecting ring

201: centrifugal pump 202: sealing gland

203: pump shaft 204: metal bellows type accumulator

205: mushroom valve 206: rubber liner

207: gas-liquid same chamber accumulator 208: inner tank accumulator

209: Piston accumulator 210: Refill port

211: Detection valve

detailed description

The metal bellows type accumulator for the shaft sealing system of the present invention and its centrifugal pump flushing system will be described in detail below with reference to the embodiments and the accompanying drawings.

As shown in FIG. 7, the metal bellows type accumulator for the shaft sealing system of the present invention comprises a steel shell 2, and a liquid inlet 5 and a liquid outlet 6 respectively formed on the side wall of the steel shell 2. a window 4 and a liquid filling port 3, an inflation port 1 formed at a top end of the steel casing 2, and a liquid discharge port 8 formed at a bottom end of the steel casing 2, the lower portion of the steel casing 2 being provided for a steel shell The liquid in 2 is cooled by a cooling coil, and the cooling water inlet 7 and the cooling water outlet 9 of the cooling coil are respectively located outside the bottom end of the steel shell 2, and the inside of the steel shell 2 is separated by an elastic mechanism 10 The upper air chamber 11 and the lower liquid chamber 12 are located. The liquid chamber 12 may also be provided with a liquid level sensor LIT connected to an external monitoring system for remote control. The elastic mechanism 10 constitutes an air chamber 11 in the upper part of the steel shell 2, and the air chamber 11 communicates with the inflation port 1 at the top end of the steel shell 2. The air chamber 11 located at the upper portion and the liquid chamber 12 at the lower portion are not in communication with each other, and liquid and gas separation is achieved by this method.

The elastic mechanism 10 includes a partition bottom plate 101 and a metal bellows 102. The bottom port of the metal bellows 102 is fixedly and sealingly connected to the upper end surface of the partition bottom plate 101. The metal bellows 102 The upper port is fixedly and sealingly connected to the connecting ring 103 integrally formed on one of the inner side walls of the upper end of the steel casing 2. The connecting ring 103 is located above the liquid filling port 3 and is integrally formed with the steel shell 2 . Therefore, when the liquid leaks to the low point, the residual liquid can be forcibly replenished from the refill port 3 while maintaining the original system pressure, so that the liquid level is restored to the normal position.

The metal bellows 102 is formed by welding or pressing a formed metal strip, which is integrally formed with the steel shell 2 and is also integrally formed with the partition base 101. However, its length can be freely expanded and contracted, so that the volume of the elastic mechanism 10 composed of the partition base 101 and the metal bellows 102 can be changed as needed at any time during operation.

Since the volume of the accumulator = the volume of the gas in the accumulator + the volume of the liquid in the accumulator. The volume of the accumulator is a constant. When the volume of the liquid in the accumulator increases, the volume of the gas in the accumulator decreases. If the volume of the chamber changes and the mass of the gas does not change, then when the volume of the gas does not change, then As the volume decreases, the pressure in the entire accumulator increases; otherwise the pressure in the accumulator decreases.

The metal bellows type accumulator for the shaft sealing system of the present invention can replace the following three accumulators:

The gas-liquid co-compressor used in the standard seal flushing plan 53A, the bile accumulator used in the standard seal flushing plan 53B, and the piston accumulator used in the standard seal flushing plan 53C.

The metal bellows accumulator is dimensioned in exactly the same way as the accumulators in the standard seal flushing plans 53A, 53B and 53C of the API682 standard.

The replacement metal bellows accumulator retains all of the advantages of the accumulators in the standard seal flush plans 53A, 53B and 53C of the API682 standard and overcomes their shortcomings. That is to say, the metal bellows accumulator has the advantages.

Therefore, in the standard seal flushing plan 53A, the standard seal flushing plan 53B and the standard seal flushing plan 53C in the API682 standard, other components in the entire system are retained, and only the accumulator can be replaced.

As shown in FIG. 7, FIG. 8, and FIG. 9, a centrifugal pump flushing system of the present invention having a metal bellows type accumulator for a shaft sealing system includes a centrifugal pump 201 and a pump connected to the centrifugal pump 201. a sealing gland 202 on the side of the shaft 203, the sealing gland 202 is connected to the metal bellows type accumulator 204 through a pipeline, and the metal bellows type accumulator 204 includes There are: steel shells 2, respectively formed on the side walls of the steel shell 2, a liquid inlet 5, a liquid outlet 6 and a window 4, an inflating port 1 formed at the top end of the steel shell 2 and formed in the steel shell 2 at the bottom end of the liquid discharge port 8, the lower portion of the steel casing 2 is provided with a cooling coil for cooling the liquid in the steel shell 2, the cooling water inlet 7 and the cooling water outlet 9 of the cooling coil Located at the outer side of the bottom end of the steel shell 2, the inside of the steel shell 2 is separated by an elastic mechanism 10 into an air chamber 11 at the upper portion and a liquid chamber 12 at the lower portion. A liquid level sensor LIT connected to the external monitoring system may also be disposed in the liquid chamber 12. The elastic mechanism 10 constitutes an air chamber 11 in the upper part of the steel shell 2, the air chamber 11 is in communication with the inflating port 1 at the top end of the steel shell 2, and the inflating port 1 at the top end of the steel shell 2 is provided. Pressure sensor PIT.

The elastic mechanism 10 includes a partition bottom plate 101 and a metal bellows 102. The bottom port of the metal bellows 102 is fixedly and sealingly connected to the upper end surface of the partition bottom plate 101. The metal bellows 102 The upper port is fixedly and sealingly connected to the connecting ring 103 integrally formed on one of the inner side walls of the upper end of the steel casing 2.

Claims

A metal bellows type accumulator for a shaft sealing system, comprising a steel shell (2), respectively forming a liquid inlet (5) and a liquid outlet on a side wall of the steel shell (2) , a window (4) and a liquid filling port (3), an inflation port (1) formed at a top end of the steel shell (2) and a liquid discharge port (8) formed at a bottom end of the steel shell (2), The lower part of the steel shell (2) is provided with a cooling coil for cooling the liquid in the steel shell (2), and the cooling water inlet (7) and the cooling water outlet (9) of the cooling coil are respectively located The outer side of the bottom end of the steel shell (2) is characterized in that the inside of the steel shell (2) is separated by an elastic mechanism (10) into an upper air chamber (11) and a lower liquid chamber (12).
A metal bellows type accumulator for a shaft sealing system according to claim 1, wherein said elastic mechanism (10) comprises a dividing bottom plate (101) and a metal bellows (102), said The bottom port of the metal bellows (102) is fixedly and sealingly connected to the upper end surface of the partitioning plate (101), and the upper port of the metal bellows (102) is fixedly and sealingly connected integrally formed therein. On the connecting ring (103) of the inner side wall of the upper end of the steel shell (2), the connecting ring (103) is located above the liquid filling port (3).
A metal bellows type accumulator for a shaft sealing system according to claim 1 or 2, wherein said elastic mechanism (10) constitutes an air chamber (11) at an upper portion of the steel casing (2). The air chamber (11) is in communication with the gas inlet (1) at the top end of the steel shell (2).
A metal bellows type accumulator for a shaft sealing system according to claim 1 or 2, characterized in that the liquid chamber (12) is provided with a liquid level sensor connected to an external monitoring system.
A centrifugal pump flushing system having the metal bellows type accumulator according to any one of claims 1 to 3, comprising a centrifugal pump (201) and a pump shaft (203) connected to the centrifugal pump (201) a side sealing gland (202), characterized in that the sealing gland (202) is connected to a metal bellows type accumulator (204) through a pipeline, the metal bellows type accumulator (204) The steel shell (2) is formed on the side wall of the steel shell (2), the liquid inlet (5), the liquid outlet (6), the window (4) and the liquid filling port (3), respectively. a gas inlet (1) at the top end of the steel shell (2) and a liquid discharge port (8) formed at a bottom end of the steel shell (2), and a lower portion of the steel shell (2) is provided for the steel a cooling coil for cooling the liquid in the shell (2), the cooling water inlet (7) and the cooling water outlet (9) of the cooling coil are respectively located outside the bottom end of the steel shell (2), the steel shell (2) The inside is separated by an elastic mechanism (10) into an upper air chamber (11) and a lower liquid chamber (12).
The centrifugal pump flushing system according to claim 5, wherein said elastic mechanism (10) comprises a partition bottom plate (101) and a metal bellows (102), the bottom of said metal bellows (102) The port is fixedly and sealingly connected to the upper end surface of the partitioning plate (101), and the upper port of the metal bellows (102) is fixedly and sealingly connected to the inner side wall formed on the upper end of the steel casing (2) Connected to the ring (103).
A centrifugal pump flushing system according to claim 5 or 6, wherein said elastic mechanism (10) constitutes an air chamber (11) in the upper portion of the steel casing (2), said air chamber (11) and steel The inflation port (1) at the top of the casing (2) is in communication.
The centrifugal pump flushing system according to claim 5, characterized in that the liquid chamber (12) is provided with a liquid level sensor (LIT) connected to the external monitoring system.
The centrifugal pump flushing system according to claim 5, characterized in that a pressure sensor (PIT) is provided at the inflation port (1) at the top end of the steel casing (2).