Pilot-operated type pneumatic conveying automatic blowing assisting valve used for pneumatic conveying pipeline

Abstract

The invention discloses a pilot-operated type pneumatic conveying automatic blowing assisting valve used for a pneumatic conveying pipeline, which is structurally characterized in that an air inlet cavity, a pipe pushing cavity and a piston cavity are arranged in a vertical valve body, and an upper opening in the air inlet cavity is connected with an air inlet connector pipe through threads; an air inlet connector pipe controls a valve element through a spring so that the valve element can be matched with a valve seat, a pilot hole penetrating through the valve element is formed in the center of the valve element, a pilot airflow adjusting bolt is arranged at the top end of the pilot hole of the valve element, a transverse pilot air inlet hole is formed in the end face of the valve element, and a push pipe arranged at the lower end of the valve element is in clearance fit with a push pipe cavity. A through hole communicated with the push tube cavity is formed in the upper end of the push tube. The pilot valve is reasonable in structure and convenient to machine and maintain, compressed air entering the valve can be preferentially guided into the air outlet cavity and the bottom of the main piston, the pilot effect is obvious, the blockage phenomenon at the right angle and the bent angle of an existing pilot air path can be avoided, blockage is not likely to happen, long-term stable work of the valve is guaranteed, and the working efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of pneumatic conveying, and belongs to a blow-assisting valve of a pneumatic conveying system, in particular to a pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline. Background Art

[0002] The pilot-operated pneumatic conveying automatic blow-assist valve is used in the pneumatic conveying system of fly ash in power station boilers. The pilot-operated pneumatic conveying automatic blow-assist valve is a key equipment in the ash conveying system. The quality of the pilot air circuit layout design is one of the key technologies that determine whether the pilot-operated pneumatic conveying automatic blow-assist valve can work stably and long-term in the ash conveying system. The pilot air circuit is to first introduce the compressed air entering the valve into the bottom of the main piston and the push rod cavity of the valve. When the fly ash in the ash conveying pipe is conveyed away, the ash conveying pressure in the ash conveying pipe is reduced, and the pilot air entering the air outlet cavity will flow from the valve outlet through the check valve into the ash conveying pipe. In this way, the pilot air pressure introduced into the bottom of the main piston and the air outlet cavity of the valve is less than the valve core opening pressure, and the valve is in a normally closed state. When the fly ash in the ash conveying pipe is blocked, the ash conveying pressure in the ash conveying pipe increases, the outlet check valve is closed, the pilot air in the outlet cavity does not flow out, and the pilot air pressure introduced into the bottom of the main piston of the valve and the outlet cavity increases. When the pressure increases to a level greater than the valve core opening pressure, the valve opens, and the high-pressure airflow enters the ash conveying pipe through the outlet cavity, instantly increasing the pressure in the pipe before the blockage point and disturbing the airflow in the pipe to send away the blocked fly ash. The valve opens and closes when the ash pipe is blocked and empty, thereby achieving automatic continuous operation.

[0003] The pilot hole of the existing pilot plunger valve is generally designed inside the valve body, consisting of horizontal and vertical holes, with many right-angle bends and complex processing technology. The pilot plunger valve requires that the air flow rate of the pilot gas entering the main piston chamber be smaller than the air flow rate entering the outlet chamber, so the diameter of the pilot hole entering the main piston chamber is designed to be very small (about 1mm in diameter). Since the compressed air used contains water, oil and trace impurities, the long-term circulation of compressed air will cause corrosion, scaling and blockage at the right-angle bend of the pilot hole and the small hole entering the main piston chamber, causing the valve to lose its pilot function. In addition, the processing of the pilot hole in the valve body is complex and costly. Summary of the invention

[0004] The purpose of the present invention is to provide a pilot-operated pneumatic conveying automatic blowing-assisting valve for use in a pneumatic conveying pipeline. The valve has a reasonable structure and is easy to process and maintain. The compressed air entering the valve can be preferentially introduced into the air outlet cavity and the bottom of the main piston. The pilot effect is obvious, and the blockage phenomenon at right angles and curved corners can be solved. The valve is not easy to be blocked, thereby ensuring long-term stable operation of the valve and improving work efficiency.

[0005] The purpose of the present invention is achieved in this way: a pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline, the structure of the pilot-operated pneumatic conveying automatic blow-assisting valve is that a valve cavity, a push tube cavity and a piston cavity are arranged in sequence from top to bottom in an upright valve body, an air intake interface pipe is connected to the upper opening in the valve cavity through a thread, the air intake interface pipe controls the valve core through a spring, so that the valve core and the valve seat are matched, a pilot hole penetrating the valve core is arranged at the center of the valve core, a pilot airflow regulating bolt is arranged at the top of the pilot hole of the valve core, a pilot airway air intake hole that is horizontally connected to the valve cavity and the pilot hole is arranged on the end face of the valve core, and a pilot airway airway that is horizontally connected to the valve cavity and the pilot hole is arranged on the valve core. A push tube arranged at the lower end of the core is matched with a clearance of the push tube cavity, a through hole connected to the push tube cavity is arranged at the upper end of the push tube, a composite piston composed of a main piston and a secondary piston is installed in the piston cavity, a guide column is arranged at the center of the upper end surface of the secondary piston, the guide column and the inner wall of the push tube are slidably matched, a central through hole penetrating the composite piston and the guide column is arranged at the center of the composite piston, a shrinkage hole is arranged at the lower part of the central through hole, an air outlet cavity connected to the push tube cavity is arranged on the valve body at the side of the push tube cavity, an interface is arranged at the outlet end of the air outlet cavity, a valve cover and a valve body bolt seal are arranged at the bottom of the piston cavity, and a linkage air inlet interface is arranged at the center of the valve cover.

[0006] The compressed air of the present invention enters the valve cavity through the air inlet interface pipe of the valve, and a small amount of compressed air flows into the push tube cavity through the pilot hole on the valve core, and then is divided into two parts. One part enters the air outlet cavity through the end hole on the push tube, and the other part enters the central through hole of the secondary piston and enters the bottom of the main piston of the main piston cavity. When a large amount of ash in the ash conveying pipe is transported to the ash bin, the pressure of the compressed air in the ash conveying pipe is reduced, the pressure of the valve outlet connected to the ash conveying pipe is reduced, and the pilot air in the air inlet cavity will flow into the ash conveying pipe from the valve check outlet, so that the pilot air pressure introduced into the bottom of the main piston and the valve cavity is less than the valve core opening pressure, and the valve does not start. When the fly ash in the ash conveying pipe is blocked, the ash conveying pressure in the ash conveying pipe increases, the outlet check valve is closed, the pilot air in the air outlet cavity does not flow out, and the pilot air pressure introduced into the bottom of the main piston of the valve and the valve cavity increases. When the pressure increases to be greater than the valve core opening pressure, the valve starts, and the high-pressure airflow enters the ash conveying pipe from the outlet to blow away the blocked fly ash. The valve opens and closes when the ash pipe is blocked or emptied, thus achieving automatic and continuous operation.

[0007] The present invention sets a pilot hole at the center of the valve core, and designs a central through hole at the center of the auxiliary piston and the main piston, so that the compressed air entering the valve is preferentially introduced into the air outlet cavity and the bottom of the main piston. The design is ingenious and the pilot effect is obvious. Since the pilot hole structure is simple in design, it is easy to process and maintain, and there is no right-angle bend and no clogging will occur.

[0008] The invention has a reasonable structure and is easy to process and maintain. It realizes that the compressed air entering the valve is preferentially introduced into the air outlet cavity and the bottom of the main piston. The pilot action is sensitive, and the blockage phenomenon at right angles and curved corners is solved. It is not easy to be blocked, thus ensuring the long-term stable operation of the valve and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will be further described below in conjunction with the accompanying drawings. Figure 1 is a cross-sectional structural schematic diagram of embodiment 1 of the present invention, Figure 2 It is a schematic cross-sectional structural diagram of embodiment 2 of the present invention. DETAILED DESCRIPTION

[0010] A pilot-operated pneumatic conveying automatic blow-assist valve used in a pneumatic conveying pipeline, such as Figure 1 , Figure 2As shown in the figure, the structure of the pilot-operated pneumatic conveying automatic blow-assisting valve is that a valve cavity, a push tube cavity and a piston cavity are arranged in sequence from top to bottom in an upright valve body 1, an air intake interface pipe 2 is connected to the upper opening in the valve cavity through a thread, and the air intake interface pipe 2 controls the valve core 5 through a spring 3, so that the valve core 5 and the valve seat are matched, a pilot hole 7 penetrating the valve core 5 is arranged at the center of the valve core 5, a pilot air flow adjustment bolt 4 is arranged at the top of the pilot hole 7 of the valve core 5, a pilot air path air intake hole 6 that is horizontally connected to the valve cavity and the pilot hole 7 is arranged on the end face of the valve core 5, a push tube 8 arranged at the lower end of the valve core 5 is matched with the push tube cavity clearance, and a push tube 8 is arranged at the upper end of the push tube 8 A through hole 9 connected to the push tube cavity is provided, and a composite piston composed of a main piston 16 and a secondary piston 11 is installed in the piston cavity. A guide column 19 is provided at the center of the upper end surface of the secondary piston 11, and the guide column 19 is slidably matched with the inner wall of the push tube 8. A central through hole 14 penetrating the composite piston and the guide column is provided at the center of the composite piston, and a shrinkage hole 15 is provided at the lower part of the central through hole 14. An air outlet cavity 10 connected to the push tube cavity is provided on the valve body 1 at the side of the push tube cavity, and an interface 12 is provided at the outlet end of the air outlet cavity 10. A valve cover 17 is provided at the bottom of the piston cavity to seal with the valve body bolts, and a linkage air intake interface 18 is provided at the center of the valve cover 17. The structure of the composite piston is that the secondary piston 11 is provided at the center above the main piston 16, and the diameter of the main piston 16 is larger than that of the secondary piston 11, forming a stepped disc shape. The assembly structure of the air intake interface pipe 2 is that a reduced diameter air intake port 20 is provided at the upper end of the air intake interface pipe inner cavity, an internal thread is provided on the inner wall of the air intake port, and an external thread is provided on the outer wall of the lower end of the air intake interface pipe 2. The air intake interface pipe 2 is connected to the upper opening of the valve body 1 through a thread, and the upper end of the spring 3 installed in the air intake interface pipe 2 is matched with the lower end surface of the reduced diameter air intake port 20, and the valve core 5 is installed at the lower end of the spring 3. The length of the push tube 8 is longer than the length of the push tube cavity. The center of the center hole of the valve core 5, the push tube 8, and the composite piston are on the same straight line. The piston circumferential surfaces of the main piston 16 and the auxiliary piston 11 constituting the composite piston are respectively provided with annular grooves, and the sealing member 13 is installed in the annular groove, and the composite piston is sealed and matched with the piston cavity through the sealing member 13. The pilot air hole mechanism is composed of the central circular hole of the valve core 5, the pilot air inlet hole 6 of the valve core 5 end face transversely connected to the valve cavity, the through hole 9 set at the upper end of the push tube 8, the central through hole 14 and the shrinkage hole 15. The pilot air is divided into two parts after passing through the pilot air inlet hole 6 and the pilot hole 7. One part flows into the air outlet cavity 10 through the through hole 9 set at the upper end of the push tube 8, and the other part flows into the bottom of the main piston of the piston cavity through the central through hole 14 and the shrinkage hole 15. The aperture of the central through hole 14 located in the main piston 16 is smaller than that of the central through hole 14 located in the auxiliary piston 11 and the guide column. There are two air outlet holes on the air outlet cavity 10. One hole is installed with a pressure gauge to observe the valve body pressure, and the other hole is a linkage air outlet hole 21 connected to the linkage air inlet 18 of the next blow-assist valve through a hose.

Claims

1. A pilot-operated pneumatic conveying automatic blow-assisting valve for use in a pneumatic conveying pipeline, characterized in that: The structure of the pilot-operated pneumatic conveying automatic blow-assisting valve is that a valve cavity, a push tube cavity and a piston cavity are arranged in sequence from top to bottom in an upright valve body (1); an air intake interface pipe (2) is connected to the upper opening of the valve cavity through a thread; the air intake interface pipe (2) controls a valve core (5) through a spring (3) so that the valve core (5) and the valve seat are matched; a pilot hole (7) penetrating the valve core (5) is arranged at the center of the valve core (5); a pilot air flow regulating bolt (4) is arranged at the top end of the pilot hole (7) of the valve core (5); a pilot air path air intake hole (6) horizontally connecting the valve cavity and the pilot hole (7) is arranged on the end face of the valve core (5); a push tube (8) arranged at the lower end of the valve core (5) is matched with the push tube cavity gap; a push tube (8) is arranged at the upper end of the push tube (8) A through hole (9) connected to the push tube cavity is arranged, a composite piston composed of a main piston (16) and a secondary piston (11) is installed in the piston cavity, a guide column (19) is arranged at the center of the upper end surface of the secondary piston (11), the guide column (19) is slidably matched with the inner wall of the push tube (8), a central through hole (14) penetrating the composite piston and the guide column is arranged at the center of the composite piston, a shrinkage hole (15) is arranged at the lower part of the central through hole (14), an air outlet cavity (10) connected to the push tube cavity is arranged on the valve body (1) at the side of the push tube cavity, an interface (12) is arranged at the outlet end of the air outlet cavity (10), a valve cover (17) is arranged at the bottom of the piston cavity to be sealed with the valve body bolts, and a linkage air inlet interface (18) is arranged at the center of the valve cover (17).

2. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: The structure of the composite piston is that a secondary piston (11) is arranged at the center of a main piston (16), the diameter of the main piston (16) is larger than that of the secondary piston (11), and the main piston (16) is in a stepped disc shape.

3. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: The assembly structure of the air intake interface pipe (2) is as follows: a reduced diameter air intake port (20) is arranged at the upper end of the inner cavity of the air intake interface pipe, an internal thread is arranged on the inner wall of the air intake port, and an external thread is arranged on the outer wall of the lower end of the air intake interface pipe (2). The air intake interface pipe (2) is connected to the upper end of the valve body (1) through threads, and the upper end of a spring (3) is installed in the air intake interface pipe (2) to match the lower end surface of the reduced diameter air intake port (20), and a valve core (5) is installed at the lower end of the spring (3).

4. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: The length of the push tube (8) is longer than the length of the push tube cavity.

5. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: The centers of the center holes of the valve core (5), the push tube (8) and the composite piston are on the same straight line.

6. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: Circular grooves are respectively arranged on the circumferential surfaces of the main piston (16) and the auxiliary piston (11) constituting the composite piston. A sealing member (13) is installed in the circular groove. The composite piston is sealed with the piston cavity through the sealing member (13).

7. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: The pilot air hole mechanism comprises a central circular hole of a valve core (5), a pilot air inlet hole (6) on the end face of the valve core (5) which is transversely connected to the valve cavity, a through hole (9) arranged at the upper end of a push tube (8), a central through hole (14) and a shrinkage hole (15). The pilot air is divided into two parts after passing through the pilot air inlet hole (6) and the pilot hole (7). One part flows into the air outlet cavity (10) through the through hole (9) arranged at the upper end of the push tube (8), and the other part flows into the bottom of the main piston of the piston cavity through the central through hole (14) and the shrinkage hole (15). The aperture of the central through hole (14) in the main piston (16) is smaller than the aperture of the central through hole (14) in the auxiliary piston (11) and the guide column.

8. The pilot-operated pneumatic conveying automatic blow-assisting valve used in a pneumatic conveying pipeline according to claim 1 is characterized in that: The air outlet cavity (10) has two air outlet holes, one hole is provided with a pressure gauge to observe the valve body pressure, and the other hole is a linkage air outlet hole (21) connected to the linkage air inlet (18) of the next blow-assisting valve through a hose.

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