Minimum reflux valve suitable for high-pressure ammonium pump

Abstract

The utility model discloses a minimum reflux valve suitable for a high-pressure ammonium pump, which is used for a production device in chemical fertilizer and chemical industry, and aims to solve the cavitation phenomenon of the valve and achieve long-period on-line safe operation. Comprising a valve body and valve element assembly, a filler assembly and a fastening assembly. The valve body and valve element assembly comprises a lower valve body, a valve seat, a valve element and a valve body. An outlet runner is arranged at the upper end of the valve seat; the outlet flow channel is provided with two layers of outlet flow channels, and the two layers of outlet flow channels are provided with different numbers of small overflowing holes; the lower end of the valve body is provided with a bolt hole and is provided with a bolt; a bolt hole is formed in the upper end of the valve body, and a bolt is installed in the bolt hole. The upper part of the valve body is a filler box body; a filler bin is arranged in the filler box body; the packing assembly comprises a packing assembly body, a packing gland and a packing pressing plate. The fastening assembly comprises a nut and a filler bolt; and the valve body and the lower valve body are fixed through a nut.

Description

Technical Field

[0001] The invention discloses a minimum reflux valve suitable for a high-pressure ammonium pump, which is used in a production device of fertilizer chemical industry and relates to the technical field of design and manufacture of the minimum reflux valve of a high-pressure ammonium pump on a methylammonium production line. Background Art

[0002] The minimum reflux valve of a centrifugal pump will encounter several different working conditions during operation. When the centrifugal pump is started, the main line is in a closed state under the action of the check valve, and the valve stem is in a fully open position to ensure sufficient reflux of the pump; when the outlet hydraulic pressure of the centrifugal pump gradually increases, the check valve on the main line gradually opens, the valve stem is in a gradually closed position, and the recirculation reflux gradually decreases; when the centrifugal pump is working normally, the hydraulic pressure of the main line will fully open the check valve, the bypass control valve will fully open and close, and the recirculation system will be completely cut off; when the working conditions change or an abnormality occurs, the check valve disc will be in different positions as the hydraulic pressure of the main line changes, and the bypass valve will be adjusted to different positions to meet the minimum flow of the centrifugal pump; when the centrifugal pump stops running, the main line hydraulic pressure drops, and the check valve disc closes to prevent liquid backflow from damaging the pump;

[0003] In the fertilizer chemical plant, there is a very important valve, which is the minimum reflux valve of the ammonium pump. The operating conditions of the valve are about 18.0MPa before the valve and about 0.5MPa after the valve. The medium is methylammonium liquid. During use, the small flow rate is required to be adjustable, and the large flow rate must be guaranteed to pass. In the case of frequent flash evaporation, it will cause great damage to the regulating head and guide position of the valve core. The minimum reflux valve of the pump, also called the automatic recirculation control valve, is installed at the outlet of the pump to provide the most economical and reliable protection for the centrifugal pump. It can recirculate a small amount of medium when the pump is running at low load, ensure the minimum flow of the pump, and maintain the stable operation of the pump. , with a check function to prevent the medium from flowing back; the flash evaporation that occurs in the production process is the phenomenon that after the high-pressure saturated liquid enters the relatively low-pressure container, due to the sudden drop in pressure, these saturated liquids become saturated steam and saturated liquid under part of the container pressure; flash evaporation is extremely harmful in production management, not only causing great waste, but also posing great safety and environmental risks. In order to solve this technical problem, domestic and foreign countries currently basically use single-seat valves or candied haws string-type valve cores, or increase the hardness of the material. Even so, the service life of this type of reflux valve is very short, and basically cannot exceed 1 year. Utility Model Content

[0004] The object of the present invention is to provide a high-pressure ammonium pump minimum reflux valve, which can effectively solve the valve cavitation phenomenon and achieve long-term online safe operation;

[0005] The technical solution of the present invention includes a valve body and valve core assembly, a packing assembly and a fastening assembly:

[0006] The valve body and valve core assembly comprises a lower valve body, a valve seat, a valve core and a valve body; an outlet flow channel is arranged at the upper end of the valve seat; the outlet flow channel is arranged in two layers, and different numbers of flow holes are arranged on the two layers of outlet flow channels;

[0007] A bolt hole is provided at the lower end of the valve body and a bolt is installed thereon; a bolt hole is provided at the upper end of the valve body and a bolt is installed thereon; the upper part of the valve body is a stuffing box body, and a stuffing bin is provided inside the stuffing box body;

[0008] The packing assembly comprises a packing assembly, a packing gland and a packing pressure plate;

[0009] The fastening assembly includes a nut and a packing bolt;

[0010] The lower valve body is fixed to the valve body by a nut;

[0011] The packing assembly, the packing gland, and the packing pressure plate are sequentially installed in the packing bin arranged in the packing box at the upper end of the valve body. The packing pressure plate is fixed by the packing bolts and nuts arranged therein and seals the packing bin;

[0012] The valve core is provided with a corresponding first valve head and a second valve head, the first valve head is a first valve head sealing surface, the second valve head is a second sealing surface, and the two sealing surfaces are used for adjustment; the larger the opening of the valve, the smaller the scouring and cavitation of the valve core by the relative medium.

[0013] The first valve head of the valve core has only one inclined surface without a large angle change, so that the medium will not produce cavitation on it. The second valve head is a segmented spherical shape, which plays an absolute flow control role and can make the flow control more precise.

[0014] An inclined chamfer C is provided on the inner circle of the lower end of the valve body, and the inclined surface of the chamfer C is inclined 150 degrees outward from the inner circle to the vertical line of the inner circle of the valve body; the 150 degree chamfer can prevent the valve seat and the valve body from being squeezed and deformed when the nut is tightened, and it is difficult to remove the valve seat later;

[0015] The upper end diameter of the valve core is larger than the lower end diameter, and an upwardly inclined guiding slope is formed at the intersection of the large and small diameters. The guiding slope forms a buffer chamber above the second valve head.

[0016] The beneficial effects of the utility model are as follows:

[0017] 1. There are two valve heads. When the openings of the first valve head and the second valve head are both 50% at the same time, the flow area of ​​the first valve head in contact with the valve seat is much larger than that of the second valve head, and is even equal to the inlet flow channel area at the lower end of the valve seat. When the flow rate does not change, the flow areas of the two valve heads will change, and the flow rates of the medium passing through the two valve heads will also be different, so the cavitation caused is also different. There is basically no cavitation phenomenon on the first valve head, which can ensure the service life of the sealing surface;

[0018] 2. A larger flow channel is set on the valve seat to provide a certain buffer for the medium during the flow process, while ensuring that there is enough flow channel space to meet the large flow rate;

[0019] 3. The outlet flow channel at the upper end of the valve seat and the valve core guide inclined surface move upward, so that a larger buffer chamber is formed between the upper part of the second valve head and the valve seat, which can prevent the medium from bursting instantly;

[0020] 4. There is no inclined surface on the upper end of the second valve head on the valve core, so the medium will not be washed on the second valve head, which effectively ensures the adjustment linearity and prolongs the service life;

[0021] 5. The outlet flow channel of the valve seat is set as a two-layer outlet flow channel structure. The number of small holes set on the two layers of outlet flow channels is different. It is used in environments with different flow rates. By adjusting the valve stem up and down, different flow channels can be selected. Therefore, different flow rates can be effectively controlled, reducing the cavitation of the valve core by the medium and effectively playing a role in noise reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the assembly structure of the present invention;

[0023] Figure 2 For the present invention Figure 1 Schematic diagram of the enlarged structure of circle A in the middle.

[0024] in:

[0025] Lower valve body-01, nut-02, valve seat-03, outlet flow channel-301, valve core-04, first valve head-401, second valve head-402, valve body-05, packing assembly-06, packing gland-07, packing pressure plate-08, packing bolt-09. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments.

[0027] In order to more clearly show the structure and use of the present invention, the best embodiment of the present invention is given below:

[0028] Embodiment 1: Structure of the present invention

[0029] See also Figure 1 and 2 : Including valve body and valve core assembly, packing assembly and fastening assembly:

[0030] The valve body and valve core assembly includes a lower valve body 01, a valve seat 03, a valve core 04 and a valve body 05; an outlet flow channel 301 is provided at the upper end of the valve seat 03; in order to meet the needs of different flow rates, the outlet flow channel 301 is provided with a two-layer outlet flow channel, and a plurality of flow holes are provided on the outlet flow channel. The number of flow holes provided on the two-layer outlet flow channels is different, and can be selected for use;

[0031] For the purpose of fixing, a bolt hole is provided at the lower end of the valve body 05, and a bolt is installed in the bolt hole. A bolt hole is also provided at the upper end of the valve body 05, and a bolt is installed therein. The upper part of the valve body 05 is a stuffing box, and a stuffing bin is provided inside the stuffing box. The stuffing assembly 06, the stuffing gland 07, and the stuffing pressure plate 08 are sequentially loaded into the stuffing bin. The stuffing pressure plate 08 is fixed by the provided stuffing bolts 09 and nuts, and plays the role of sealing the stuffing bin after being fixed.

[0032] The fastening assembly includes a nut 02 and a packing bolt 09;

[0033] The lower valve body 01 is fixedly connected to the valve body 05 and the lower valve body 01 by a nut 02;

[0034] The valve core 04 is provided with a corresponding first valve head 401 and a second valve head 402. The first valve head 401 is a first valve head sealing surface, and the second valve head 402 is a second sealing surface. The two sealing surfaces can be adjusted by moving the valve stem up and down, that is, the larger the opening of the valve, the smaller the scouring and cavitation of the valve core 04 by the relative medium. In order to accurately control the flow rate, the first valve head 401 of the valve core 04 is only provided with an inclined surface without a large angle change, so the medium will not generate cavitation on it. The second valve head 402 is a segmented spherical shape, which plays an absolute flow control role and can make the flow control more accurate.

[0035] The contact surface between the inner circle of the lower end of the valve body 05 and the valve seat 03 is provided with an inclined chamfer C. The inclined surface of the chamfer C extends outward from the inner circle to the perpendicular line of the inner circle of the valve body 05. o Degrees, set to 15 o The chamfer can prevent the valve seat 03 and the valve body 05 from being squeezed and deformed when the nut 02 is tightened, which may make it difficult to remove the valve seat 03 later.

[0036] See also Figure 1 and2 , with the direction indicated by the arrow in the figure as upward, the diameter of the upper end of the valve core 04 is larger than the diameter of the lower end, and an upwardly inclined guide slope with a smaller lower end and a larger upper end is formed at the intersection of the large and small diameters, and the guide slope forms a buffer chamber above the second valve head 402;

[0037] Figure 2 Point C is the angle of the inclined plane 15 o , Figure 2 Point B in the figure is the extrusion deformation area during installation;

[0038] Figure 1 The arrow at the bottom of the middle indicates the direction of the fluid inlet, and the arrow to the left indicates the direction of the fluid outlet.

[0039] Example 2: Use

[0040] See also Figure 1 and 2 : After the valve core 04 and the valve seat 03 are assembled, for example, when the process design requires a valve flow of 50%, the openings of the first valve head 401 and the second valve head 402 of the valve head 04 are both 50%. At this time, the flow area of ​​the first valve head 401 in contact with the valve seat is much larger than the flow area of ​​the second valve head 402 in contact with the valve seat, and may even be equal to the inlet flow channel area at the lower end of the valve seat. When the flow rate remains unchanged, the flow areas of the two valve heads will change. At this time, the flow rate of the medium entering the two valve heads will also be different, so the cavitation caused will also be different. There is basically no cavitation phenomenon in the first valve head, which can ensure the service life of the sealing surface.

[0041] Specifically, a larger flow channel is provided on the valve seat 03, which can provide a certain buffer for the medium during the flow process, while ensuring that there is enough flow channel space to meet the large flow rate.

[0042] The valve core 04 is configured such that the upper end diameter is larger than the lower end diameter, and an upwardly inclined guide slope can be formed at the intersection of the large and small diameters. The guide slope can form a buffer chamber above the second valve head 402, and the buffer chamber can prevent the medium from bursting instantly.

[0043] Furthermore, the outlet flow channel 301 on the upper part of the valve seat 03 is configured as a two-layer structure, and multiple small holes are arranged on the two layers of the outlet flow channel. The number of small holes arranged on each layer needs to be determined according to the size of the opening flow rate. In this way, different numbers of small holes can effectively control different flow rates and reduce cavitation of the valve core 03 by the medium. In addition, the two layers of the outlet flow channel 301 can effectively reduce noise under high pressure difference conditions.

Claims

1. A minimum reflux valve suitable for a high-pressure ammonium pump, characterized in that: Including valve body and valve core assembly, packing assembly and fastening assembly: The valve body and valve core assembly comprises a lower valve body (01), a valve seat (03), a valve core (04) and a valve body (05); an outlet flow channel (301) is arranged at the upper end of the valve seat (03); the outlet flow channel (301) is arranged as a two-layer outlet flow channel, and different numbers of flow holes are arranged on the two layers of outlet flow channels; A bolt hole is provided at the lower end of the valve body (05) and a bolt is installed thereon; a bolt hole is provided at the upper end of the valve body (05) and a bolt is installed thereon; the upper part of the valve body (05) is a stuffing box body, and a stuffing bin is provided inside the stuffing box body; The packing assembly comprises a packing assembly (06), a packing gland (07), and a packing pressure plate (08); The fastening assembly comprises a nut (02) and a packing bolt (09); The lower valve body (01) is fixed to the valve body (05) and the lower valve body (01) by a nut (02).

2. A minimum reflux valve suitable for a high-pressure ammonium pump as claimed in claim 1, characterized in that: A packing assembly (06), a packing gland (07), and a packing pressure plate (08) are sequentially installed in a packing bin arranged in a packing box at the upper end of the valve body (05); the packing pressure plate (08) is fixed by a packing bolt (09) and a nut, and seals the packing bin.

3. A minimum reflux valve suitable for a high-pressure ammonium pump as claimed in claim 1, characterized in that: The valve core (04) is provided with a corresponding first valve head (401) and a second valve head (402); the first valve head (401) is a first valve head sealing surface, and the second valve head (402) is a second sealing surface; the two sealing surfaces are used in an adjustable manner; the larger the opening of the valve, the smaller the scouring and cavitation of the valve core (04) by the relative medium.

4. A minimum reflux valve suitable for a high-pressure ammonium pump as claimed in claim 3, characterized in that: The first valve head (401) of the valve core (04) has only one inclined surface, on which the medium will not generate cavitation, and the second valve head (402) is a segmented spherical shape, which plays an absolute role in flow control.

5. A minimum reflux valve suitable for a high-pressure ammonium pump as claimed in claim 1, characterized in that: An inclined chamfer C is provided on the inner circle of the lower end of the valve body (05), and the inclined surface of the chamfer C is inclined outward from the inner circle to a perpendicular line of the inner circle of the valve body (05) at 150 degrees.

6. A minimum reflux valve suitable for a high-pressure ammonium pump as claimed in claim 1, characterized in that: The diameter of the upper end of the valve core (04) is larger than the diameter of the lower end, and an upwardly inclined guiding slope is formed at the intersection of the large and small diameters, and the guiding slope forms a buffer chamber above the second valve head (402).

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