A plunger pump with a gas collection prevention function and a control method thereof

Abstract

The application discloses a plunger pump with a gas collection prevention function and a control method thereof. The plunger pump comprises a feeding screw, a main pump body, a pressure detection device and a control system. The feeding screw is provided with a feeding screw discharge port. The main pump body comprises a material cavity and a pumping assembly. The material cavity is provided with a material cavity inlet port, and the material cavity inlet port is connected with the feeding screw discharge port. The pumping assembly is used for pumping the material in the material cavity. The pressure detection device is used for detecting the pressure change in the material cavity. The control system controls the operation of the pumping assembly according to the detection result of the pressure detection device, so as to reduce the energy consumption and prevent the gas collection. Compared with the setting of an exhaust valve or the direct installation of a material level meter to solve the gas collection problem, the application fundamentally reduces the frequency of the gas collection problem, and the detection device is in contact with the sludge through a film coating mode, so that the other components of the detection device are not directly contacted with the sludge, and the accuracy and reliability are higher than those of the direct installation of the material level meter in the material cavity.

Description

Technical Field

[0001] This invention relates to a plunger pump with anti-gas accumulation function and its control method, which is particularly suitable for plunger pumps used for conveying sludge or similar high-concentration viscous materials with a moisture content of 75% or more. Background Technology

[0002] If a sludge pump runs while the plunger pump is still operating, air will be pumped into the pipeline. When the air accumulates to a certain volume, due to the compressibility of gas and the intermittent delay characteristic of the plunger pump, all the energy transferred by the subsequent sludge in a single pumping stroke will be used to compress the gas in the pipeline. The pumping pressure of the sludge in the pipeline downstream of the gas will reach an equilibrium with the back pressure of the sludge in the pipeline upstream of the gas. The accumulated gas in the pipeline will be compressed-rebound-compressed repeatedly, resulting in pumping failure.

[0003] Current methods for addressing air accumulation in sludge plunger pump pipelines typically involve installing vent valves at the ends and middle of the pipeline. However, the location of the air accumulation is uncertain, resulting in poor venting effectiveness. Another approach involves installing a material storage hopper at the feed screw end of the plunger pump and directly mounting a level gauge on the top or side wall of the hopper to detect the material level, preventing air from entering the plunger pump. However, the stickiness and corrosiveness of sludge often cause the level gauge to malfunction. Furthermore, the root cause of air accumulation is the plunger pump's failure to effectively ensure the continuity of pumped material, leading to excessive air input during dry runs that enters the pipeline with the material, thus causing air accumulation. Therefore, it is necessary to develop a method that can monitor the air content in the pumped material, control the air content during sludge pumping, and thereby reduce the possibility of air accumulation. Summary of the Invention

[0004] In order to solve at least one of the problems existing in the background technology, the present invention provides a plunger pump with anti-gas accumulation function and its control method, which is suitable for plunger pumps that convey sludge or similar high-concentration viscous materials with a water content of more than 75%.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a plunger pump with anti-gas accumulation function, including a feeding screw, a main pump body, a pressure detection device and a control system;

[0007] The feeding screw is provided with a feeding screw inlet and a feeding screw outlet;

[0008] The main pump includes a material chamber and a pumping assembly; the material chamber is provided with a material inlet, which is connected to a feeding screw outlet; the pumping assembly is used to pump the material in the material chamber.

[0009] The pressure detection device is used to detect pressure changes within the material chamber;

[0010] The control system controls the operation of the pumping assembly based on the detection results of the pressure detection device, thereby reducing energy consumption and preventing gas accumulation in the pipeline.

[0011] Furthermore, when the pressure detection device detects that the material chamber is filled with material to the first threshold, the pressure detection device sends a signal, and the control system controls the pumping assembly to work, pumping the material out of the main pump body's material chamber.

[0012] Furthermore, when gas continuously enters the material chamber, and the pressure detection device detects that the material in the material chamber has dropped to the second threshold, the pressure detection device sends a signal, and the control system controls the pumping component to stop working or slow down the pumping speed, waiting for the material to continue filling the material chamber, until the material chamber is filled to the first threshold before restarting.

[0013] Furthermore, an opening is provided on the side of the feed screw outlet, and is connected to the opening of the pressure detection device.

[0014] Furthermore, the pressure detection device includes a housing, a detection head, a connecting rod, a first proximity switch, a second proximity switch, and an elastic diaphragm; the outer edge of the elastic diaphragm is installed between the side opening of the feeding screw outlet and the housing; the inner surface of the elastic diaphragm is connected to the detection head; the connecting rod is installed in the detection head; the first and second proximity switches are installed in the housing to detect the position of the connecting rod; the installation positions of the first and second proximity switches in the housing are adjustable; when the second proximity switch sends a signal, the control system controls the main pump to pump; when the first proximity switch sends a signal, the control system controls the main pump to stop pumping or slow down the pumping speed.

[0015] Furthermore, the housing includes a fixed frame, a connecting rod support frame, and a proximity switch mounting frame; one end flange of the fixed frame is connected and fixed to the side opening flange of the feeding screw outlet; both sides of the connecting rod support frame are connected to the proximity switch mounting frame and the fixed frame respectively through flanges and bolts; one side of the proximity switch mounting frame is machined with an oblong hole for mounting the first proximity switch and the second proximity switch.

[0016] Furthermore, each end of the connecting rod support frame has a sealing plate, and a through hole is machined in the center of the sealing plate. A linear bearing is fixed in the through hole by bolts.

[0017] Furthermore, the connecting rod is a T-shaped connecting rod, one end of which is a round rod with a threaded end, and the other end is a round plate; the T-shaped connecting rod passes through a linear bearing in the connecting rod support frame, with the threaded end facing the fixed frame and the round plate end facing the proximity switch mounting frame.

[0018] Furthermore, the detection head is a circular plate with a threaded hole machined in the center to be fixed to the T-shaped connecting rod by means of a thread.

[0019] Secondly, the present invention provides a control method for a plunger pump with anti-gas accumulation function as described above, the method comprising:

[0020] When the feeding screw starts working, the material enters through the feeding screw inlet and exits through the feeding screw outlet, then enters the material chamber of the main pump body. When the material chamber of the main pump body is filled with material, the elastic diaphragm of the pressure detection device is squeezed and deformed, pushing the internal detection head to move away from the material chamber, and driving the connecting rod to move in the same direction until the second proximity switch detects the end of the T-shaped connecting rod and sends a signal. When the plunger pump control system receives this signal, it controls the pumping assembly of the main pump body to start working, pumping the material out of the material chamber of the main pump body.

[0021] As gas continuously enters the main pump's material chamber, the material filling rate gradually decreases. When the force exerted by the material on the elastic membrane is less than the force required for the membrane to recover its deformation, the detection head moves towards the material chamber under the tension of the elastic membrane, causing the T-shaped connecting rod to move in the same direction until proximity switch number two stops sending a signal. Proximity switch number one detects the circular plate end of the T-shaped connecting rod and sends a signal. When the control system receives this signal, it controls the main pump's pumping assembly to stop working or slows down the pumping speed, waiting for material to continue filling the main pump's material chamber until it is completely filled before restarting.

[0022] Compared with the prior art, the advantages of this invention are as follows:

[0023] This invention provides a plunger pump with anti-air accumulation function and its control method. A pressure detection device is installed on the side wall of the feeding screw outlet, and two proximity switches are installed at different positions at the same horizontal level on the side wall of the device support. When the material chamber of the main pump body is completely filled with material and the material is squeezed to the elastic membrane on the side of the device, the end of the sliding rod is pushed towards the proximity switch until the proximity switch sends a signal. When the second proximity switch sends a signal, the plunger pump control system controls the main pump body to start pumping; when the first proximity switch sends a signal, the plunger pump control system controls the main pump body to stop pumping or slow down the pumping speed. This ensures the continuity of material supply in the material chamber of the main pump body and prevents the main pump body from pumping too much air into the conveying pipeline due to insufficient material, causing air accumulation in the pipeline and resulting in pumping failure.

[0024] Compared to setting up an exhaust valve or directly installing a level gauge to solve the gas collection problem, this invention fundamentally reduces the frequency of gas collection problems. By using a membrane coating method, the detection device, except for the elastic membrane, avoids direct contact with the sludge (the detection head and T-shaped connecting rod behind the elastic membrane do not directly contact the sludge due to the presence of the elastic membrane, thus avoiding unnecessary resistance to its operation due to the presence of sludge). This method is more accurate and reliable than directly installing a level gauge in the material chamber, and also extends the service life of the detection elements.

[0025] The core mechanism provided by this invention can automatically control the start-up, stop-up, or speed of operation of the plunger pump according to the filling status of the material in the main pump body's material chamber. The design of the waist-shaped hole on the side of the proximity switch mounting bracket allows for free adjustment of the distance between the two proximity switches, thereby controlling the start-up and stop interval of the plunger pump according to actual needs, improving the energy utilization rate of the plunger pump equipment, and thus achieving the purpose of energy conservation and emission reduction. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a plunger pump with anti-gas accumulation function provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the pressure detection mechanism;

[0028] Figure 3 for Figure 2 Enlarged view of a portion of the image from direction A;

[0029] In the diagram: 1-Feeding screw; 1.1-Feeding screw inlet; 1.2-Screw body; 1.3-Feeding screw outlet; 2-Pressure detection device; 2.1-Fixed frame; 2.2-Connecting rod support frame; 2.3-Proximity switch mounting frame; 2.4-Oval hole; 2.4.1-Proximity switch No. 1; 2.4.2-Proximity switch No. 2; 2.5-T-shaped connecting rod; 2.6-Linear bearing; 2.7-Detection head; 2.8-Elastic membrane; 3-Main pump body; 3.1-Material chamber; 3.2-Pumping system; 3.3-Frame; 3.4-Material chamber inlet. Detailed Implementation

[0030] Example:

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a signal connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can be described as the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms "upper," "lower," "front," "rear," "left," "right," "first," "last," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] To resolve the issue of air accumulation in the existing sludge plunger pump pipeline, refer to... Figure 1 As shown, this embodiment provides a plunger pump with anti-gas accumulation function, which mainly includes a feeding screw 1, a main pump body 3, a pressure detection device 2, and a control system (not shown).

[0034] The feeding screw 1 is used to convey and buffer materials to the main pump body 3, and is equipped with a feeding screw inlet 1.1, a screw body 1.2 and a feeding screw outlet 1.3.

[0035] The main pump body 3 is used to transport materials and mainly includes a material chamber 3.1, a pumping assembly 3.2, and a frame 3.3. A material chamber inlet 3.4 is also provided above the material chamber 3.1. The material chamber inlet 3.4 is connected to the lower part of the feeding screw outlet 1.3. The feeding screw 1 can transport the material from the feeding screw inlet 1.1 through the screw body 1.2 to the feeding screw outlet 1.3, and then enter the material chamber 3.1 through the material chamber inlet 3.4 of the main pump body 3. The material is then transported by the pumping assembly 3.2 through the pipeline.

[0036] The pressure detection device 1 is used to detect pressure changes in the material chamber 3.1. The control system controls the operation of the pumping component based on the detection results of the pressure detection device 2, thereby achieving the purpose of reducing energy consumption and preventing gas accumulation in the pipeline.

[0037] When the pressure detection device 2 detects that the material chamber 3.1 is filled to the first threshold (full), the pressure detection device 2 sends a signal, and the control system controls the pumping component 3.2 to pump the material out of the material chamber 3.1 of the main pump body. When the pressure detection device detects that the material filling rate in the material chamber gradually decreases and drops to the second threshold, the pressure detection device 2 sends a signal, and the control system controls the pumping component 3.2 to stop working or slow down the pumping speed, waiting for the material to continue filling the material chamber until the material chamber is filled to the first threshold, and then restarting. This cycle is repeated, thereby achieving the purpose of reducing energy consumption and preventing gas accumulation in the pipeline.

[0038] In one specific embodiment, an opening is provided on the side of the feed screw outlet 1.3, and is connected to the opening of the pressure detection device 2. For example... Figure 2 As shown, the pressure detection device 2 includes a housing, a detection head 2.7, a T-shaped connecting rod 2.5, a first proximity switch 2.4.1, a second proximity switch 2.4.2, and an elastic diaphragm 2.8. The housing includes a fixing frame 2.1, a connecting rod support frame 2.2, and a proximity switch mounting frame 2.3. One end flange of the fixing frame 2.1 is connected to the side opening of the feed screw 1 outlet 1.3 via flanges and bolts. Both sides of the connecting rod support frame 2.2 are connected to the proximity switch mounting frame 2.3 and the fixing frame 2.1 via flanges and bolts, respectively. The proximity switch mounting frame 2.3 has several oblong holes 2.4 machined on one side. Specifically, the outer edge of the elastic diaphragm 2.8 is located between the flange of the feed screw outlet 1.3 side opening and the flange of the pressure detection device 2 housing, and the elastic diaphragm is clamped and fixed by the two flanges using fasteners. The inner surface of the elastic diaphragm 2.8 is bonded to the detection head 2.7. The elastic membrane is characterized by its stretchability, elasticity, and corrosion resistance. The elasticity of the membrane itself enables the detection head 2.7 to achieve a self-resetting effect. In addition, the elastic membrane also serves to isolate the sludge from direct contact with other components of the detection device besides the elastic membrane.

[0039] Specifically, the connecting rod support frame 2.2 has a sealing plate at each of its left and right ends. The sealing plate is made of carbon steel. The sealing plate has a through hole in its center and two sets of linear bearings 2.6 are fixed to it with bolts. The linear bearings 2.6 can greatly reduce the friction of the T-shaped connecting rod 2.5 during operation, making it easier for it to reset.

[0040] Specifically, the detection head 2.7 is fixed to the T-shaped connecting rod 2.5 by a threaded connection. The detection head 2.7 is a circular plate with a threaded hole machined in its center; this threaded hole is a blind hole. One end of the T-shaped connecting rod 2.5 is a circular rod with a threaded end, and the other end is a circular plate. The T-shaped connecting rod 2.5 passes through the linear bearing 2.6 in the connecting rod support frame 2.2, with the threaded end facing the fixed frame 2.1 and the circular plate end facing the proximity switch mounting frame 2.3.

[0041] Specifically, proximity switch 2.4.1 and proximity switch 2.4.2 are located at different positions within the same oblong hole 2.4 of the proximity switch mounting bracket 2.3, and are used to detect the position of the circular plate of the T-shaped connecting rod 2.5. The positions of proximity switches 2.4.1 and 2.4.2 can be adjusted according to actual operating conditions to accommodate different pressure conditions generated when sludge is present in the material chamber.

[0042] Accordingly, this embodiment also provides a control method based on Figure 1 The plunger pump shown has an anti-gas-accumulation function, and the method includes:

[0043] When the feeding screw 1 starts working, the material enters through the feed inlet 1.1 and exits through the discharge outlet 1.3, then enters the material chamber 3.1 of the main pump body 3. When the material chamber 3.1 of the main pump body 3 is filled with material, the elastic membrane 2.8 of the pressure detection device 2 is squeezed and deformed, pushing the internal detection head 2.7 to move away from the material chamber 3.1, and driving the T-shaped connecting rod 2.5 to move in the same direction until the second proximity switch 2.4.2 detects the circular plate end of the T-shaped connecting rod 2.5 and sends a signal. When the plunger pump control system receives this signal, it controls the pumping system 3.2 of the main pump body 3 to start working, pumping the material out of the material chamber 3.1 of the main pump body 3.

[0044] When gas continuously enters the material chamber 3.1 of the main pump body 3, the material filling rate in the material chamber 3.1 of the main pump body 3 gradually decreases. When the force exerted by the material on the elastic membrane 2.8 is less than the force of the elastic membrane 2.8 to recover its deformation, the detection head 2.7 moves towards the material chamber 3.1 under the tension of the elastic membrane 2.8, driving the T-shaped connecting rod 2.5 to move in the same direction until the second proximity switch 2.4.2 stops sending a signal. The first proximity switch 2.4.1 detects the circular plate end of the T-shaped connecting rod 2.5 and sends a signal. When the plunger pump control system receives this signal, it controls the pumping system 3.2 of the main pump body 3 to stop working or slow down the pumping speed, waiting for the material to continue filling the material chamber 3.1 of the main pump body 3 until the material chamber 3.1 is full of material before restarting. This cycle is repeated to achieve the purpose of reducing energy consumption and preventing gas accumulation in the pipeline.

[0045] In summary, this invention provides a pressure detection device at the side wall of the feeding screw outlet and two proximity switches at different positions on the same horizontal level on the side wall of the device support. When the material chamber of the main pump body is completely filled with material and the material is squeezed to the elastic membrane on the side of the device, the end of the sliding rod is pushed towards the proximity switch until the proximity switch sends a signal. When the second proximity switch sends a signal, the plunger pump control system controls the main pump body to start pumping; when the first proximity switch sends a signal, the plunger pump control system controls the main pump body to stop pumping or slow down the pumping speed. This ensures the continuity of material supply in the material chamber of the main pump body and prevents the main pump body from pumping too much air into the conveying pipeline due to insufficient material, causing air accumulation in the pipeline and resulting in pumping failure.

[0046] Compared to setting up an exhaust valve or directly installing a level gauge to solve the gas collection problem, this invention fundamentally reduces the frequency of gas collection problems. By using a membrane coating method, the other components of the detection device, except for the elastic membrane, are prevented from directly contacting the sludge. This method is more accurate and reliable than directly installing a level gauge in the material chamber, and also extends the service life of the detection element.

[0047] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A plunger pump with anti-gas accumulation function, characterized in that, Includes a feeding screw, main pump body, pressure detection device, and control system; The feeding screw is provided with a feeding screw inlet and a feeding screw outlet; The main pump body includes a material chamber and a pumping assembly; the material chamber is provided with a material chamber inlet, and the material chamber inlet is connected to a feeding screw outlet; the pumping assembly is used to pump the material in the material chamber; The pressure detection device is used to monitor the pressure changes in the material chamber in real time. The control system controls the operation of the pumping assembly based on the monitoring results of the pressure detection device, so as to reduce energy consumption and prevent gas accumulation in the pipeline. The pressure detection device includes a housing, a detection head, a connecting rod, a first proximity switch, a second proximity switch, and an elastic membrane; the outer edge of the elastic membrane is installed between the side opening of the feeding screw outlet and the housing; the inner surface of the elastic membrane is connected to the detection head; The connecting rod is installed in the detection head; The first proximity switch and the second proximity switch are installed in the housing to detect the position of the connecting rod; The installation positions of the first and second proximity switches in the housing are adjustable; when the second proximity switch sends a signal, the control system controls the main pump to pump; when the first proximity switch sends a signal, the control system controls the main pump to stop pumping or slow down the pumping speed.

2. The plunger pump with anti-gas accumulation function as described in claim 1, characterized in that, When the pressure detection device detects that the material chamber is filled with material to the first threshold, the pressure detection device sends a signal, and the control system controls the pumping component to work, pumping the material out of the material chamber of the main pump body.

3. The plunger pump with anti-gas accumulation function as described in claim 1, characterized in that, When gas continuously enters the material chamber, and the pressure detection device detects that the material in the material chamber has dropped to the second threshold, the pressure detection device sends a signal, and the control system controls the pumping component to stop working or slow down the pumping speed, waiting for the material to continue filling the material chamber, until the material chamber is filled to the first threshold before restarting.

4. The plunger pump with anti-gas accumulation function as described in claim 1, characterized in that, An opening is provided on the side of the feed screw outlet and is connected to the opening of the pressure detection device.

5. The plunger pump with anti-gas accumulation function as described in claim 1, characterized in that, The housing includes a fixed frame, a connecting rod support frame, and a proximity switch mounting frame; one end flange of the fixed frame is connected and fixed to the side opening flange of the feeding screw outlet; both sides of the connecting rod support frame are connected to the proximity switch mounting frame and the fixed frame respectively through flanges and bolts; one side of the proximity switch mounting frame is machined with an oblong hole for installing the first proximity switch and the second proximity switch.

6. The plunger pump with anti-gas accumulation function as described in claim 5, characterized in that, The connecting rod support frame has a sealing plate at each of its left and right ends. Each sealing plate has a through hole machined in its center, and a linear bearing is fixed in the through hole by bolts.

7. The plunger pump with anti-gas accumulation function as described in claim 1, characterized in that, The connecting rod is a T-shaped connecting rod, one end of which is a round rod with a threaded end, and the other end is a round plate. The T-shaped connecting rod passes through a linear bearing in the connecting rod support frame, with the threaded end facing the fixed frame and the round plate end facing the proximity switch mounting frame.

8. The plunger pump with anti-gas accumulation function as described in claim 7, characterized in that, The detection head is a circular plate with a threaded hole machined in the center to be fixed to the T-shaped connecting rod by thread.

9. A control method for the plunger pump with anti-gas accumulation function as described in claim 1, characterized in that, The method includes: When the feeding screw starts working, the material enters through the feeding screw inlet and exits through the feeding screw outlet, then enters the material chamber of the main pump body. When the material chamber of the main pump body is filled with material, the elastic diaphragm of the pressure detection device is squeezed and deformed, pushing the internal detection head to move away from the material chamber, and driving the connecting rod to move in the same direction until the second proximity switch detects the end of the T-shaped connecting rod and sends a signal. When the plunger pump control system receives this signal, it controls the pumping assembly of the main pump body to start working, pumping the material out of the material chamber of the main pump body. As gas continuously enters the main pump body's material chamber, the material filling rate gradually decreases. When the force exerted by the material on the elastic membrane is less than the force exerted by the elastic membrane to recover its deformation, the detection head moves towards the material chamber under the tension of the elastic membrane, causing the T-shaped connecting rod to move in the same direction until the second proximity switch stops sending a signal. The first proximity switch detects the circular plate end of the T-shaped connecting rod and sends a signal. When the control system receives this signal, it controls the main pump body's pumping assembly to stop working or slows down the pumping speed, waiting for the material to continue filling the main pump body's material chamber until the chamber is completely filled before restarting.

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