High-pressure constant-pressure centrifugal pump and intelligent energy-saving control system

Abstract

The invention discloses a high-pressure constant-pressure centrifugal pump and an intelligent energy-saving control system. The centrifugal pump comprises a pump body and an impeller. The impeller comprises a front cover plate, a rear cover plate and backward bent blades located in the front cover plate and the rear cover plate. The impeller further comprises short blades fixedly connected to the outer edges of the front cover plate and the rear cover plate and evenly distributed in the circumferential direction of the impeller. The short blades are straight blades extending outwards in the radial direction of the impeller, the end of each backward-bent blade is connected with one short blade, and a plurality of short blades are arranged between every two adjacent backward-bent blades. The cross section of an internal flow channel of a volute of the pump body is a peanut shell type cross section comprising two parallel arcs. According to the centrifugal pump, the lift can be improved, and the constant pressure can be kept.

Description

Technical Field

[0001] The present invention relates to the field of centrifugal pumps, and in particular to a high-pressure constant-pressure centrifugal pump and an intelligent energy-saving control system. Background Art

[0002] Centrifugal pumps work by using the centrifugal force generated by the rotation of the impeller. They are widely used in industries such as petrochemicals, construction, agriculture, and pharmaceuticals. Traditional centrifugal pumps have a simple structure and consist of a pump body, impeller, pump cover, shaft, and bearings. Figure 1 As shown. However, traditional centrifugal pumps have the disadvantages of low efficiency, low head and low pressure, and cannot meet the application requirements of some special industries, such as the fire protection industry. In particular, fire pumps not only need to increase the head but also achieve the purpose of constant pressure. In other occasions, centrifugal pumps are required to have a higher outlet pressure. At present, the common methods on the market to improve efficiency and head include increasing the impeller diameter, increasing the blade outlet angle, increasing the speed, increasing the number of blades, and using multi-stage pumps. Although these methods are simple and effective, in actual applications, due to problems with processing technology and energy consumption, traditional improvement methods often require greater energy consumption and higher manufacturing costs.

[0003] In addition, with the popularization of intelligence and automation, centrifugal pump control systems are used more and more frequently in engineering. In order to maximize the control effect of the system, it is necessary to continuously strengthen the optimization of the centrifugal pump control system during practical application. However, in the current centrifugal pump intelligent control system, its monitoring link has a certain lag, and it is impossible to perform real-time monitoring according to the specific operating conditions of the centrifugal pump. This is insufficient to respond to emergencies that occur during the operation of the centrifugal pump, and managers need to intervene manually. In reality, managers of centrifugal pump control systems have incomplete knowledge of the control system and cannot make very accurate judgments and operations. Therefore, it not only affects the effect of the centrifugal pump control system, but also wastes a certain amount of energy. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a high-pressure constant-pressure centrifugal pump and an intelligent energy-saving control system, which improves the structure of the impeller and the structure of the volute of the pump body to achieve the functions of pressurization, lift and constant pressure. At the same time, in order to better control the operating conditions of the pump to achieve the purpose of energy saving and improve efficiency, a new intelligent control system is proposed.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A high-pressure constant-pressure centrifugal pump comprises a pump body and an impeller; the impeller comprises a front cover plate, a rear cover plate, and backward-curved blades located inside the front cover plate and the rear cover plate;

[0007] The impeller further comprises short blades fixedly connected to the outer edges of the front cover plate and the rear cover plate and uniformly arranged along the circumference of the impeller; the short blades are straight blades extending radially outward from the impeller, one short blade is connected to the end of each backward curved blade, and a plurality of short blades are arranged between two adjacent backward curved blades;

[0008] The internal flow channel cross section of the volute of the pump body is a peanut shell cross section including two parallel arcs.

[0009] Furthermore, two of the short blades are arranged between two adjacent backward-curved blades.

[0010] An intelligent energy-saving control system including a high-pressure constant-pressure centrifugal pump, and also including a flow control valve, an electromagnetic flow meter, a pressure transmitter, a central controller, a cavitation tank and a pressure-stabilizing tank;

[0011] The pressure transmitter is located at the inlet and outlet of the centrifugal pump, and is used to measure the inlet pressure and outlet pressure of the centrifugal pump and feed it back to the central controller in real time;

[0012] The electromagnetic flowmeter is located at the outlet of the pressure stabilizing tank and is used to measure the outlet flow of the centrifugal pump at constant pressure and provide real-time feedback to the central controller;

[0013] The flow control valve is located after the electromagnetic flow meter to facilitate controlling the outlet flow of the centrifugal pump.

[0014] The central controller is electrically connected to the motor of the centrifugal pump, the flow control valve, the electromagnetic flowmeter and the pressure transmitter, and is used to calculate the head of the centrifugal pump in real time and calculate the performance characteristic curve of the pump in real time.

[0015] Furthermore, the central controller also estimates and predicts based on the set threshold of head, flow or efficiency using a Bayesian regularized BP neural network; when the Bayesian regularized BP neural network adapts to the setting of head, flow or efficiency when the prediction error is less than the set threshold, it automatically adjusts the motor speed of the centrifugal pump and the flow control valve to make the centrifugal pump operate under the set working conditions.

[0016] Furthermore, the set operating conditions of the centrifugal pump include the most efficient operating conditions or the most energy-saving operating conditions.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention improves the impeller structure of a traditional centrifugal pump, adds a short blade extending radially at the end of each rotating blade of a traditional closed impeller, and also arranges two short blades extending radially at the impeller outlet between two adjacent rotating blades; in order to adapt to the improved impeller, the cross-section of the volute area of ​​the impeller outlet is also improved to a peanut shell shape, so that the fluid flowing out from one side of the short blade can re-enter the flow channel between the short blades to be repeatedly circulated and pressurized to obtain energy, thereby achieving the purpose of simultaneously increasing pressure and improving lift.

[0019] 2. Since the outlet angle of the short blades of the impeller is vertical, according to the theoretical characteristic curve of the pump head flow, it can play a constant pressure role compared with the structure of the traditional impeller.

[0020] 3. The intelligent energy-saving control system of the present invention sets a pressure transmitter at the inlet and outlet of the pump to monitor the pump head in real time, sets an electromagnetic flowmeter at the outlet of the pressure-stabilizing tank, and connects the pressure transmitter, electromagnetic flowmeter, flow control valve and motor through a central intelligent controller. The performance curve of the pump can be obtained in real time and the speed of the motor and the flow control valve can be automatically adjusted to ensure that the pump always operates in the best state; and a BRBP neural network is built into the central controller for adaptive control, thereby achieving the purpose of intelligent control and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic cross-sectional view of a conventional centrifugal pump.

[0022] Figure 2 FIG. 1 is a top view of an impeller of a centrifugal pump according to an embodiment of the present invention.

[0023] Figure 3 It is a three-dimensional diagram of an impeller of a centrifugal pump according to an embodiment of the present invention.

[0024] Figure 4 Schematic cross-sectional view of a centrifugal pump according to an embodiment of the present invention.

[0025] Figure 5 Schematic diagram of the theoretical characteristic curve of the pump's head and flow rate.

[0026] Figure 6 Schematic diagram of an intelligent energy-saving control system according to an embodiment of the present invention.

[0027] Figure 7 Schematic diagram of the control flow of the central controller in the intelligent control system of the embodiment.

[0028] In the figure, 1 is the impeller, 2 is the short blade, 3 is the backward curved blade, 4 is the pump body, 5 is the arc-shaped pressurized pump chamber, 6 is the flow control valve, 7 is the electromagnetic flow meter, 8 is the pressure transmitter, 9 is the central controller, 10 is the cavitation tank, and 11 is the pressure-stabilizing tank. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] The diagrams only show the components related to the present invention, rather than the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation can be changed at will, and the layout of the components may be more complicated. The structures, proportions, sizes, etc. shown in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0031] like Figure 2 and Figure 3 As shown, the impeller 1 of the centrifugal pump has blades including backward curved blades 3 located inside the front cover plate and the rear cover plate, and short blades 2 fixedly connected to the outer edges of the front cover plate and the rear cover plate and arranged evenly arranged along the circumference of the impeller. The short blades 2 are straight blades extending radially outward from the impeller. A short blade 2 is connected to the end of each backward curved blade 3, and two short blades 2 are arranged between two adjacent backward curved blades 3.

[0032] like Figure 4 As shown, in order to adapt to the impeller 1, the internal flow passage section of the volute is increased by an arc surface on the basis of the traditional single arc surface, that is, the internal flow passage section of the volute is a peanut shell section containing two parallel arcs. When the impeller 1 is working, a part of the fluid pressurized by the impeller leaks from one side of the short blade 2, and due to the effect of gravity, re-enters the short blade 2 in the circumference of the impeller, and is pressurized again by the impeller 1, thereby realizing repeated circulation and pressurization of the fluid, so that the fluid obtains more energy, which is conducive to increasing the head and reducing the occurrence of cavitation. Since the short blade 2 is a straight blade extending in the radial direction, it can maintain the stability of the head and flow rate, and achieve the effect of constant pressure.

[0033] According to the basic equation of a centrifugal pump:

[0034]

[0035] Where H is the theoretical head, Q is the theoretical flow rate, v2 is the circumferential velocity of the liquid at the impeller outlet, n is the impeller speed, β2 is the flow angle, D2 is the outlet diameter, and b2 is the blade outlet width.

[0036] The outlet angle of the short blade is vertical. Figure 5 The theoretical characteristic curve of pump head flow rate not only improves the head but also plays a role of constant pressure compared with the traditional impeller structure (β2<90°).

[0037] like Figure 6 As shown, an embodiment of the present invention also provides an intelligent energy-saving control system including the above-mentioned centrifugal pump, including a flow control valve 6, an electromagnetic flowmeter 7, a pressure transmitter 8, a central controller 9, a cavitation tank 10, and a pressure-stabilizing tank 11. Among them, the pressure transmitter 8 is located at the inlet and outlet positions of the centrifugal pump, and is used to measure the inlet pressure and outlet pressure of the pump and feed back to the central controller 9 in real time. The electromagnetic flowmeter 7 is located at the outlet position of the pressure-stabilizing tank 11, and is used to measure the outlet flow of the pump at constant pressure and feed back to the central controller 9 in real time. The flow control valve 6 is located after the electromagnetic flowmeter 7 to facilitate the control of the outlet flow. The central controller 9 connects the flow control valve 6, the electromagnetic flowmeter 7, the pressure transmitter 8 and the motor of the pump, and can calculate the performance characteristic curve of the pump (including the flow-head curve, the efficiency-flow characteristic curve and the shaft power flow characteristic curve) in real time.

[0038] like Figure 6 and Figure 7 As shown, the central controller 9 will monitor the performance characteristic curve of the pump in real time, set the threshold of head, flow or efficiency, and use Bayesian Regularization BP (BRBP) neural network for estimation and prediction. When the prediction error of BRBP neural network is less than 5%, the setting of adaptive head, flow or efficiency can be adopted to achieve the purpose of intelligent control.

[0039] The Bayesian regularized BP neural network is based on the BP neural network. The Bayesian regularization rule is introduced to train the BP neural network. It does not require precise setting of network parameters. The training speed is very fast, the generalization performance is good and far exceeds the BP neural network.

[0040] The central controller 9 automatically adjusts the motor speed and the flow control valve 6 according to the adaptive control of the BRBP neural network to reduce cavitation and maintain efficient operation, so that the centrifugal pump operates under the set working conditions, thereby achieving the best state. The central controller 9 can also manually adjust the motor speed and the flow control valve 6 according to the efficiency threshold and the flow threshold to achieve the set working conditions, thereby achieving the energy saving requirements. The BRBP neural network can use the real-time monitored pump performance data as a training set, and verify the real-time prediction results to ensure that the error is always less than 5%.

[0041] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A high-pressure constant-pressure centrifugal pump, characterized in that: It comprises a pump body and an impeller (1); the impeller (1) comprises a front cover plate, a rear cover plate, and backward curved blades (3) located inside the front cover plate and the rear cover plate; The impeller (1) further comprises short blades (2) fixedly connected to the outer edges of the front cover plate and the rear cover plate and uniformly arranged along the circumference of the impeller (1); the short blades (2) are straight blades extending radially outwardly along the impeller (1); one short blade (2) is connected to the end of each backward curved blade (3), and a plurality of short blades (2) are arranged between two adjacent backward curved blades (3); The internal flow channel cross section of the volute of the pump body is a peanut shell cross section including two parallel arcs.

2. The high-pressure constant-pressure centrifugal pump according to claim 1, characterized in that: Two of the short blades (2) are arranged between two adjacent backward-curved blades (3).

3. An intelligent energy-saving control system including the high-pressure constant-pressure centrifugal pump according to claim 1, characterized in that: It also includes a flow control valve (6), an electromagnetic flow meter (7), a pressure transmitter (8), a central controller (9), a cavitation tank (10) and a pressure stabilizing tank (11); The pressure transmitter (8) is located at the inlet and outlet of the centrifugal pump, and is used to measure the inlet pressure and outlet pressure of the centrifugal pump, and feed it back to the central controller (9) in real time; The electromagnetic flowmeter (7) is located at the outlet of the pressure stabilizing tank (11) and is used to measure the outlet flow of the centrifugal pump at constant pressure and to feed back to the central controller (9) in real time; The flow control valve (6) is located after the electromagnetic flow meter (7) to facilitate controlling the outlet flow of the centrifugal pump. The central controller (9) is electrically connected to the motor of the centrifugal pump, the flow control valve (6), the electromagnetic flowmeter (7) and the pressure transmitter (8) and is used to calculate the head of the centrifugal pump in real time and calculate the performance characteristic curve of the pump in real time.

4. The intelligent energy-saving control system according to claim 3 is characterized in that: The central controller (9) also uses a Bayesian regularized BP neural network to estimate and predict based on a set threshold of the head, flow or efficiency; when the Bayesian regularized BP neural network has a prediction error less than the set threshold, it adapts to the setting of the head, flow or efficiency and automatically adjusts the motor speed of the centrifugal pump and the flow control valve (6) to enable the centrifugal pump to operate under the set working conditions.

5. The intelligent energy-saving control system according to claim 3 is characterized in that: The set operating conditions for centrifugal pump operation include the most efficient operating conditions or the most energy-saving operating conditions.

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