A low-lift self-priming pump for conveying easily gasified media

Abstract

A low-lift self-priming pump for conveying easily gasified media includes a centrifugal pump, a jet pot, a shunt pressure-reducing pipe and a self-priming auxiliary device; the jet pot is connected to the centrifugal pump inlet through the jet pot outlet pipe at the bottom; the top of the jet pot is provided with an automatic exhaust self-priming device; the jet pot has a jet pump; the upper chamber of the shunt pressure-reducing pipe is connected to the jet pump discharge pipe, the lower chamber is connected to the centrifugal pump outlet, and the lower chamber outlet is divided into two paths: one is connected to the jet pump pressure pipeline; the other is connected to the pressure pipeline of the self-priming auxiliary device. The self-priming pump transfers the energy of the high-speed and high-pressure medium at the outlet of the centrifugal pump to the low-speed and low-pressure medium in the jet pot through the jet pump to reduce the outlet pressure of the centrifugal pump; the self-priming auxiliary device increases the suction height of the pump to avoid the medium from vaporizing due to the reduction of the liquid surface pressure during the suction process, thereby meeting the user's requirements for conveying easily gasified media at a low lift.

Description

Technical Field

[0001] The invention belongs to the technical field of self-priming pump devices, in particular to a low-lift self-priming pump for conveying easily gasifiable media. Background Art

[0002] With the development of petrochemical industry, flammable, explosive and gasifiable media are becoming more and more common. The suction height of ordinary self-priming pumps is limited by the local atmospheric pressure and the cavitation margin of the pump itself, and it is impossible to achieve the submerged lifting of such media. If a long-axis submersible pump is used for lifting, the motor is above the liquid surface and the rotor components are below the liquid surface. The over-long shaft is difficult to process, and the swing amplitude of the pump shaft is amplified, resulting in a short bearing life and high maintenance frequency; and the over-long shaft needs to be supported by multi-point sliding bearings. Once the sliding bearings are not well lubricated, it is easy to cause dry grinding, sparks, and ignite the flammable and explosive gases in the tank, causing a fire. Therefore, long-axis submersible pumps are not suitable.

[0003] A jet pump is a fluid machine, a device that uses the jet of a working fluid to transport fluid. There are no moving parts in the jet pump, and it has the advantages of simple structure, reliable operation, no leakage, self-priming ability, no sparks due to friction between parts, easy processing and convenient comprehensive utilization. It is especially suitable for the transportation of flammable, explosive and easily gasified media. However, the jet pump needs a high-pressure liquid source as the motive force during the jet process. Usually, a pressure water tank is used or a water pump is set up separately outside the main pump to provide a high-pressure liquid source for the jet pump. This not only increases the cost of the pump, but also takes up a large space.

[0004] To solve the above problems, the CN210218140U patent document discloses an "automatic exhaust self-priming pump" that can be used to transport easily gasified media. The self-priming pump consists of a centrifugal pump, a self-priming auxiliary device and an exhaust tank. The centrifugal pump diverts the high-pressure medium it outputs through a reflux pipeline (i.e., a pressure source pipeline) as the power source of the self-priming auxiliary device in the liquid storage tank. The self-priming auxiliary device delivers the medium in the liquid storage tank to the exhaust tank, and the gas contained in the medium is discharged through the automatic exhaust self-priming device at the top of the exhaust tank, and then delivered to the centrifugal pump through the discharge pipe at the bottom of the exhaust tank, and is directly discharged by the centrifugal pump. This self-priming pump requires that the outlet pressure of the centrifugal pump be high enough, otherwise it cannot meet the power requirements of the self-priming auxiliary device. However, the centrifugal pump has a high outlet pressure and a high head, which cannot meet the requirements of some users for low head of the self-priming pump. Even at the outlet of the high-head pump, it is difficult to reduce the excessively high outlet pressure to the level required by the user by the pressure reducing valve. Summary of the invention

[0005] In order to solve this technical problem, the present invention improves the automatic exhaust self-priming pump and provides a low-lift self-priming pump for conveying easily gasified media to meet the user's low-lift requirements for the self-priming pump.

[0006] The low-lift self-priming pump for conveying easily gasifiable media provided by the present invention comprises a centrifugal pump, a jet pot, a shunt pressure-reducing pipe and a self-priming auxiliary device;

[0007] The centrifugal pump and the jet tank are placed on the ground; the self-priming auxiliary device is placed in a liquid storage tank (the liquid storage tank is located underground);

[0008] The jet pot is connected to the inlet of the centrifugal pump through the jet pot outlet pipe at the bottom; the top of the jet pot is provided with an automatic exhaust self-priming device; and the jet pot is provided with a jet pump;

[0009] The shunt pressure-reducing pipe is divided into a lower chamber and an upper chamber by a blind plate, wherein the upper chamber is connected to the discharge pipe of the jet pump, and the lower chamber is connected to the outlet of the centrifugal pump. The outlet of the lower chamber is divided into two paths: one path is connected to the pressure pipeline of the jet pump through the pressure-reducing reflux pipe; the other path is connected to the pressure pipeline of the self-priming auxiliary device through the pressure source pipeline;

[0010] The discharge outlet of the self-priming auxiliary device is connected to the inlet pipe of the jet pot through a discharge pipe; the inlet pipe of the jet pot extends into the upper part of the jet pot, and is fixed in the jet pot through an upper partition installed on one side of the upper part of the inner wall of the jet pot, and its outlet protrudes out of the upper partition; a lower partition lower than the upper partition and staggered with the upper partition is installed on the other side of the upper part of the inner wall of the jet pot, and the jet pump is fixed in the jet pot through the lower partition.

[0011] The self-priming auxiliary device is a jet pump, a water wheel pump, or a turbocharger.

[0012] If the gas discharged from the automatic exhaust self-priming device needs to be introduced into the liquid storage tank, the automatic exhaust self-priming device is connected to the liquid storage tank through the exhaust flange and the exhaust pipe on the top thereof.

[0013] The working principle of the present invention is as follows: before the self-priming pump is started, the jet tank is first filled with medium. After the pump is started, the centrifugal pump extracts the medium in the jet tank and discharges it from the pump outlet. After entering the lower cavity of the shunt and pressure-reducing tube, it is divided into two paths: one path is used as a high-pressure liquid source and flows from the pressure-reducing reflux pipe to the jet pump in the jet tank. After the medium serving as the high-pressure liquid source enters the jet pump from the jet pump pressure pipeline, the jet pump absorbs the medium in the jet tank. The energy of the high-pressure and high-speed medium flowing out of the centrifugal pump outlet is transferred to the low-pressure and low-speed medium in the tank. Through the energy transfer, the medium is mixed into a mixed medium with a flow rate and pressure lower than the medium at the centrifugal pump outlet, enters the upper cavity of the shunt and pressure-reducing tube, and is discharged, thereby achieving the effect of reducing the outlet pressure of the centrifugal pump. The other way flows to the self-priming auxiliary device in the liquid storage tank through the pressure source pipeline, which serves as the high-pressure liquid source of the self-priming auxiliary device. After the medium enters the self-priming auxiliary device through the pressure pipeline, the self-priming auxiliary device absorbs the medium in the liquid storage tank. After the two are mixed, they enter the upper part of the jet tank through the discharge pipe and the jet tank inlet pipe, flow to the lower part of the jet tank through the gap between the upper and lower partitions, and then enter the centrifugal pump through the jet tank outlet pipe. The gas in the jet tank inlet pipeline is pushed into the jet tank by the medium and then floats up, and is discharged to a safe place through the automatic exhaust self-priming device, or introduced into the liquid storage tank through the exhaust flange and exhaust pipe.

[0014] Beneficial effects of the present invention:

[0015] The present invention transfers the energy of the high-speed and high-pressure medium at the outlet of the centrifugal pump to the low-speed and low-pressure medium in the jet tank through the shunt pressure-reducing pipe, the jet tank and the jet pump, and realizes the effect of reducing the outlet pressure of the centrifugal pump through the momentum exchange and mixing of the two; the medium conveying mode is changed from the negative pressure suction type of the ordinary centrifugal pump to the positive pressure push type through the self-priming auxiliary device, thereby increasing the suction height of the pump, and preventing the centrifugal pump from being unable to suck up the medium due to vaporization caused by the reduction of liquid surface pressure during the medium suction process. The cooperation of the two can meet the user's requirement for low head for conveying easily vaporized medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0017] Explanation of symbols in the figure: 1. Self-priming auxiliary device, 2. Liquid storage tank, 21. Discharge pipe, 22. Pressure pipeline, 3. Exhaust pipe, 4. Jet tank, 41. Jet tank inlet pipe, 42. Upper partition, 43. Exhaust flange, 44. Automatic exhaust self-priming device, 45. Jet pump discharge pipe, 46. Lower partition, 47. Jet pump, 48. Jet pump pressure pipeline, 49. Jet tank outlet pipe, 5. Diverter and pressure reducing pipe, 51. Upper chamber, 52. Blind plate, 53. Lower chamber, 54. Pressure reducing reflux pipe, 55. Pressure source pipeline, 6. Centrifugal pump. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] The embodiment of the low-lift self-priming pump for conveying easily gasifiable medium of the present invention is as follows: Figure 1 As shown, it includes a centrifugal pump 6, a jet pot 4, a shunt pressure reducing pipe 5 and a self-priming auxiliary device 1.

[0020] The centrifugal pump and the jet tank are placed on the ground; the self-priming auxiliary device is placed in the liquid storage tank 2; the self-priming auxiliary device can be a jet pump, a water wheel pump or a turbocharger.

[0021] The jet tank 4 is connected to the inlet of the centrifugal pump through the jet tank outlet pipe 49 at the bottom; the top of the jet tank is provided with an automatic exhaust self-priming device 44, which is connected to the liquid storage tank through the exhaust flange 43 and the exhaust pipe 3 at the top of the jet tank, and the gas exhausted by the automatic exhaust self-priming device is introduced into the liquid storage tank; the jet tank is provided with a jet pump 47.

[0022] The shunt pressure reducing pipe 5 is divided into a lower chamber 53 and an upper chamber 51 by a blind plate 52, wherein the upper chamber is connected to the jet pump discharge pipe 45, and the lower chamber is connected to the outlet of the centrifugal pump. The outlet of the lower chamber is divided into two paths: one is connected to the jet pump pressure pipeline 48 through the pressure reducing reflux pipe 54 to provide power for the jet pump; the other is connected to the pressure pipeline 22 of the self-priming auxiliary device through the pressure source pipeline 55 to provide a pressure source for the self-priming auxiliary device.

[0023] The discharge port of the self-priming auxiliary device is connected to the discharge pipe 21 ( Figure 1 The middle discharge pipe 21 is an inner tube of a double-layer tube, the lower end of which is connected to the discharge port of the self-priming auxiliary device, the upper end of the annular cavity formed between the outer tube and the inner tube of the double-layer tube is connected to the pressure source pipeline 55 through the pressure pipeline 22, and the lower end is connected to the pressure source inlet of the self-priming auxiliary device) and is connected to the jet pot inlet pipe 41; the jet pot inlet pipe extends into the upper part of the jet pot, and is fixed in the jet pot by an upper partition 42 installed on one side of the upper part of the inner wall of the jet pot, and its outlet protrudes out of the upper partition; a lower partition 46 is installed on the other side of the upper part of the inner wall of the jet pot, which is lower than the upper partition and staggered with the upper partition in space, and the jet pump is fixed in the jet pot through the lower partition.

Claims

1. A low-lift self-priming pump for conveying easily gasified media, characterized in that: It comprises a centrifugal pump (6), a jet pot (4), a diversion and pressure-reducing pipe (5) and a self-priming auxiliary device (1); The centrifugal pump and the jet tank are placed on the ground; the self-priming auxiliary device is placed in the liquid storage tank (2); The jet pot is connected to the inlet of the centrifugal pump through the jet pot outlet pipe (49) at the bottom of the jet pot; an automatic exhaust self-priming device (44) is provided on the top of the jet pot; and a jet pump (47) is provided in the jet pot; The shunt pressure reducing pipe is divided into a lower chamber (53) and an upper chamber (51) by a blind plate (52), wherein the upper chamber is connected to the jet pump discharge pipe (45), and the lower chamber is connected to the outlet of the centrifugal pump, and the outlet of the lower chamber is divided into two paths: one path is connected to the jet pump pressure pipeline (48) through the pressure reducing return pipe (54); and the other path is connected to the pressure pipeline (22) of the self-priming auxiliary device through the pressure source pipeline (55); The discharge outlet of the self-priming auxiliary device is connected to the jet pot inlet pipe (41) through a discharge pipe (21); the jet pot inlet pipe extends into the upper part of the jet pot and is fixed in the jet pot through an upper partition (42) installed on one side of the upper part of the inner wall of the jet pot, and its outlet protrudes out of the upper partition; a lower partition (46) is installed on the other side of the upper part of the inner wall of the jet pot, which is lower than the upper partition and has a space staggered with the upper partition, and the jet pump is fixed in the jet pot through the lower partition.

2. The low-lift self-priming pump for conveying easily gasifiable media according to claim 1, characterized in that: The self-priming auxiliary device is a jet pump, a water wheel pump or a turbocharger.

3. The low-lift self-priming pump for conveying easily gasifiable media according to claim 1 or 2, characterized in that: The automatic exhaust self-priming device is connected to the liquid storage tank through an exhaust flange (43) on the top and an exhaust pipe (3).

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