An electric pump with high concentration of hydrogen peroxide and its cooling control method

Abstract

This invention provides an electric pump for a high-concentration hydrogen peroxide medium, comprising a stator winding and a stator core constituting the stator, and a rotor magnet and a rotor sleeve constituting the rotor. The stator and rotor are encapsulated in a cavity formed by a front end cover and a rear end cover. Liquid flows from the front end to the rear end of the cavity, closely attached to the rotor. An adjusting needle cone is located at the center of the rear end of the cavity to control the forward and backward movement of the rotor to adjust the liquid flow rate. This invention also provides a cooling control method for the electric pump for a high-concentration hydrogen peroxide medium. This invention allows hydrogen peroxide to be introduced into the motor, utilizing the convective heat transfer of the hydrogen peroxide to remove heat from the motor, thereby preventing the motor temperature from becoming too high. It can effectively control the return flow rate, avoiding excessive power loss while ensuring sufficient cooling circuit flow to prevent dangerous overheating of the high-concentration hydrogen peroxide.

Description

Technical Field

[0001] This invention relates to an electric pump for high-concentration hydrogen peroxide medium and its cooling control method. Background Technology

[0002] A typical electric pump uses a common centrifugal pump structure, where a medium such as hydrogen peroxide enters through the pump inlet and passes sequentially through an inducer and an impeller. The low-pressure, low-velocity hydrogen peroxide is drawn in by the inducer and then driven by the high-speed rotating impeller, thus gaining a large amount of kinetic energy. The pump outlet exhibits an expansion angle, converting the kinetic energy of the liquid that has passed through the impeller into pressure potential energy, ultimately transforming the low-pressure hydrogen peroxide into high-pressure hydrogen peroxide, thereby pressurizing the fluid medium.

[0003] High-concentration hydrogen peroxide generally refers to hydrogen peroxide concentrations exceeding 90%, with commonly used concentrations being 90%, 95%, and 98%. Due to its excellent energy properties, high-concentration hydrogen peroxide is frequently used as a high-energy propellant in rocket engines.

[0004] However, high-concentration hydrogen peroxide is highly susceptible to thermal decomposition, with the decomposition rate increasing exponentially with temperature. Therefore, in electric pumps using hydrogen peroxide as the medium, it is crucial to accurately control the temperature of the hydrogen peroxide medium in the cooling circuit to prevent the excessive decomposition of high-concentration hydrogen peroxide, which could lead to an explosion.

[0005] A typical example is the hydrogen peroxide kerosene self-pressurization power system disclosed in Chinese invention patent application number CN202010646520.5, which uses an electric pump with a centrifugal pump structure. When used with high-concentration hydrogen peroxide medium, the above-mentioned problems exist. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an electric pump with a high concentration of hydrogen peroxide as the medium and its cooling control method. This electric pump with a high concentration of hydrogen peroxide as the medium can introduce hydrogen peroxide into the motor, and through the convective heat transfer of hydrogen peroxide, remove the heat from inside the motor, thereby preventing the motor temperature from becoming too high. The cooling control method of this electric pump with a high concentration of hydrogen peroxide as the medium can effectively control the return flow rate, on the one hand avoiding excessive effective power loss, and on the other hand ensuring sufficient cooling circuit flow.

[0007] The present invention is achieved through the following technical solutions.

[0008] The present invention provides an electric pump for high-concentration hydrogen peroxide medium, comprising stator windings and stator core constituting the stator, rotor magnets and rotor sheath constituting the rotor, wherein the stator and rotor are encapsulated in a cavity formed by a front end cover and a rear end cover, and liquid flowing from the front end to the rear end is in close contact with the rotor in the cavity. An adjusting needle cone is located at the center of the rear end of the cavity to control the forward and backward movement of the rotor to adjust the liquid flow rate.

[0009] The liquid is a high concentration of hydrogen peroxide.

[0010] An impeller is installed at the front end of the rotor, and an inducer is installed at the front end of the impeller. The inducer is locked by a locking nut. The locking nut, the inducer, and the impeller are all fixed on the rotor core. The front end of the front cover is a volute assembly for liquid to flow in. Between the front end cover and the volute assembly, an energy-absorbing block and an energy-absorbing spring are installed to buffer the fluid impact energy.

[0011] The rotor magnet is fitted inside the rotor sheath, which completely isolates the rotor magnet from the liquid inside the cavity.

[0012] The adjusting pin cone at the rear end of the rotor is fixed to a linear stepper motor. The conical end of the adjusting pin cone cooperates with the return hole inside the rotor core to form an adjustable needle valve. The maximum diameter of the adjusting pin cone is smaller than the inner diameter of the rotor core.

[0013] The adjusting needle cone also has a patch resistor fixed to the rear end cover. The patch resistor is used to measure the wall temperature in contact with the hydrogen peroxide fluid. There are four patch resistors, evenly distributed along the circumference.

[0014] A shielding sleeve is installed inside the cavity, directly opposite the rotor magnet. The shielding sleeve is equipped with a first sealing ring, a second sealing ring, a third sealing ring, and a fourth sealing ring to isolate the liquid. The shielding sleeve is made of polyetheretherketone.

[0015] This invention also provides a cooling control method for an electric pump using a high-concentration hydrogen peroxide medium, comprising the following steps:

[0016] ① Obtain the real-time temperature value y(kT) at the current time kT and the target temperature y d The temperature deviation e(k) of (kT), the error value at the current moment, and the temperature change rate Δe(k) at the previous moment;

[0017] ② Fuzzyize the temperature deviation e(k) and the temperature change rate Δe(k) to obtain the corresponding fuzzy output u. e (k) and u Δe (k);

[0018] ③ Adjust the gain coefficient K until there is no overshoot in the temperature response curve;

[0019] ④ Replace the medium with high-concentration hydrogen peroxide and conduct the test.

[0020] In step ③, adjusting the gain coefficient K involves using the dichotomy method to continuously change the output of K, starting the electric pump delivery system, using water as the test medium, and observing the temperature response curve.

[0021] In step ②, the controller output is Δx(k) = K(u)e (k)+u Δe (k)).

[0022] The beneficial effects of this invention are as follows: hydrogen peroxide can be introduced into the motor, and the heat inside the motor can be removed by the convective heat transfer of hydrogen peroxide, thereby preventing the motor temperature from becoming too high; the return flow rate can be effectively controlled, on the one hand avoiding excessive loss of effective power, and on the other hand ensuring sufficient cooling circuit flow to avoid danger caused by high concentration hydrogen peroxide temperature; and the spring energy absorption device can effectively reduce the impact of instantaneous pressure fluctuations on the internal structure of the electric pump. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of at least one embodiment of the present invention;

[0024] Figure 2 yes Figure 1 A schematic diagram of the three-dimensional structure;

[0025] Figure 3 This is a schematic diagram of the control link of at least one embodiment of the present invention.

[0026] In the diagram: 100 - volute assembly, 110 - locking nut, 120 - inducer, 130 - impeller, 140 - rotor core, 150 - front screw assembly, 160 - front inner seal ring, 161 - front outer seal ring, 170 - sliding bearing, 180 - stator winding, 190 - stator core, 200 - first seal ring, 201 - second seal ring, 202 - third seal ring, 203 - fourth seal ring, 210 - sliding bearing Bearing, 220-outer screw assembly, 240-inner screw assembly, 250-rear external seal ring, 260-rear internal seal ring, 270-connecting frame, 280-motor screw assembly, 290-linear stepper motor, 300-surface resistor, 310-adjusting pin taper, 320-rear end cover, 330-front end cover, 340-rotor magnet, 350-rotor sleeve, 360-shielding sleeve, 370-energy absorption block, 380-energy absorption spring. Detailed Implementation

[0027] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0028] Example 1

[0029] like Figure 1 , Figure 2An electric pump for a high-concentration hydrogen peroxide medium is shown, comprising a stator winding 180 and a stator core 190 constituting the stator, a rotor magnet 340 and a rotor sheath 350 constituting the rotor. The stator and rotor are encapsulated in a cavity formed by a front end cover 330 and a rear end cover 320. Liquid flows from the front end to the rear end of the cavity and is in close contact with the rotor. An adjusting needle cone 310 is located at the center of the rear end of the cavity to control the forward and backward movement of the rotor to adjust the liquid flow rate.

[0030] Example 2

[0031] Based on Example 1, the liquid is a high concentration of hydrogen peroxide.

[0032] Example 3

[0033] Based on Embodiment 1, an impeller 130 is installed at the front end of the rotor, and an inducer 120 is installed at the front end of the impeller 130. The inducer 120 is locked by a locking nut 110. The locking nut 110, the inducer 120, and the impeller 130 are all fixed on the rotor core 140. The front end of the front cover 330 is for the volute assembly 100 to receive liquid. Between the front end cover 330 and the volute assembly 100, an energy-absorbing block 370 and an energy-absorbing spring 380 are installed to buffer the fluid impact energy.

[0034] Example 4

[0035] Based on Embodiment 1, the rotor magnet 340 is fitted inside the rotor sleeve 350, and the rotor sleeve 350 completely isolates the rotor magnet 340 from the liquid inside the cavity.

[0036] Example 5

[0037] Based on Embodiment 1, the adjusting pin cone 310 at the rear end of the rotor is fixed to the linear stepper motor 290. The conical end of the adjusting pin cone 310 cooperates with the return hole inside the rotor core 140 to form an adjustable needle valve. The maximum diameter of the adjusting pin cone 310 is smaller than the inner diameter of the rotor core 140.

[0038] Example 6

[0039] Based on embodiment 5, the adjusting needle cone 310 also has a patch resistor 300 fixed on the side of the rear end cover 320. The patch resistor 300 is used to measure the wall temperature in contact with the hydrogen peroxide fluid. There are four patch resistors 300, which are evenly distributed along the circumference.

[0040] Example 7

[0041] Based on Embodiment 1, a shielding sleeve 360 ​​is installed in the cavity directly opposite the rotor magnet 340. The shielding sleeve 360 ​​is equipped with a first sealing ring 200, a second sealing ring 201, a third sealing ring 202, and a fourth sealing ring 203 for isolating liquid. The shielding sleeve 360 ​​is made of polyetheretherketone.

[0042] Example 8

[0043] Based on the above embodiments, the system comprises four parts: a centrifugal pump assembly, a high-speed motor assembly, an adjustable needle valve assembly, and an energy absorption device assembly. The centrifugal pump assembly pressurizes the fluid. The high-speed motor assembly drives the impeller, which is fixedly connected to the rotor, to rotate at high speed. The adjustable needle valve assembly regulates the flow rate of the return flow within the electric pump's internal cavity, adjusting the flow rate in real time based on temperature feedback to ensure the temperature of the hydrogen peroxide within the cavity remains within a safe range. The energy absorption device assembly absorbs and stores energy, converting pressure potential energy into elastic potential energy. By absorbing the impact energy of the fluid in the pipeline, it prevents water hammer from causing damage to the electric pump's internal cavity.

[0044] I. Centrifugal Pump Assembly

[0045] The centrifugal pump assembly includes a volute assembly 100, a locking nut 110, an inducer 120, and an impeller 130.

[0046] Casing assembly 100. Casing assembly 100 serves as the housing, inlet, and outlet of the centrifugal pump.

[0047] Locking nut 110. Locking nut 110 secures the inducer and impeller to the rotor core 140. Locking nut 100 is threadedly connected to the rotor core 140.

[0048] Inducer 120. The inducer 120 can entrain the fluid medium, thereby increasing the static pressure of the fluid, entraining the fluid into the impeller, and reducing the static positive suction pressure of the centrifugal pump.

[0049] Impeller 130. The impeller 130 axially enters the medium and radially throws the medium out. Through centrifugal force, it does work on the fluid, turning the low-pressure fluid into a high-pressure fluid, thus achieving fluid pressurization.

[0050] II. High-speed motor assembly

[0051] The high-speed motor assembly includes a rotor core 140, a screw assembly 150, a front inner seal ring 160, a front outer seal ring 161, a sliding bearing 170, a stator winding 180, a stator core 190, a first seal ring 200, a second seal ring 201, a third seal ring 202, a fourth seal ring 203, a sliding bearing 210, a screw assembly 220, a rear end cover 320, a front end cover 330, a rotor magnet 340, a rotor sheath 350, a shielding sleeve 360, and a colloid filling the space between the motor stator and the housing. This colloid is used to fill the gaps around the stator, thereby reinforcing and stabilizing the stator.

[0052] Rotor core 140. The rotor core is supported by sliding bearings 170 and 210. It is fixed to the inducer 120 and impeller 130 by locking nut 110. There is a central return hole inside the rotor core, and the return channel returns the hydrogen peroxide medium that enters the inner cavity from the impeller gap to the front end of the inducer.

[0053] Screw assembly 150 is used to secure the volute assembly 100 and the front cover 330.

[0054] The front inner sealing ring 160 and the front outer sealing ring 161 are used to fix the seal between the volute assembly 100 and the front end cover 330 to prevent liquid leakage.

[0055] The sliding bearing 170 is used to support the rotor core 140 and serves as a connector between the rotor core 140 and the front end cover 300, thereby reducing the frictional resistance experienced by the rotor core 140.

[0056] The stator consists of the stator winding 180 and the stator core 190, which generates a rotating magnetic field to drive the rotor to rotate.

[0057] The first sealing ring 200, the second sealing ring 201, the third sealing ring 202, and the fourth sealing ring 203 achieve a seal between the shielding sleeve 360 ​​and the front end cover 330 and the rear end cover 320 of the motor, preventing hydrogen peroxide inside the motor from entering the motor stator.

[0058] The sliding bearing 210 is used to support the rotor core 140 and reduce the frictional resistance experienced by the rotor core 140.

[0059] Screw assembly 220 is used to fix the front end cover 330 and the rear end cover 320.

[0060] The rear cover 290 has four functions: first, it connects to the sliding bearing 210 and provides a force support point for the sliding bearing 210; second, it connects to the front cover 330 and serves as part of the motor housing; third, it provides support for the connecting frame 270 of the adjustable needle valve assembly; and fourth, it contacts the shielding sleeve and achieves isolation of the hydrogen peroxide medium through the third sealing ring 202 and the fourth sealing ring 203.

[0061] The front cover 330 serves four functions. First, it acts as a mounting base to secure the entire motor to the frame. Second, it connects to the volute assembly 100, positioning and fixing it. Third, it connects to the sliding bearing 170, providing a support point for the bearing. Fourth, it contacts the shielding sleeve, achieving isolation of the hydrogen peroxide medium through the first sealing ring 200 and the second sealing ring 201. Fifth, it provides support for the energy-absorbing block 370 and the energy-absorbing spring 380 of the energy-absorbing device assembly.

[0062] The rotor magnet 340, made of neodymium iron boron, is divided into two semicircles and adsorbed onto the rotor core 140. It is isolated from the internal peroxide components by the rotor sleeve 350. Under the electromagnetic influence generated by the stator, it provides torque.

[0063] The rotor sheath 350 is connected to the rotor core 140 by welding. Its function is to protect the rotor magnet 340 and prevent the hydrogen peroxide inside the motor from coming into contact with the rotor magnet 340 and reacting.

[0064] The shielding sleeve 360 ​​serves three purposes. First, it is made of polyetheretherketone (PEEK), a non-metallic material, which helps reduce high-frequency eddy current losses. Second, the high strength of PEEK ensures that the shielding sleeve 360 ​​can withstand high internal pressure, preventing it from rupturing due to excessive pressure. Third, in conjunction with the first sealing ring 200, the second sealing ring 201, the third sealing ring 202, and the fourth sealing ring 203, it isolates the stator from the internal fluids of the motor, preventing them from contacting and reacting.

[0065] The colloid is filled into the gaps inside the motor stator, thereby further fixing the stator and preventing it from loosening.

[0066] III. Adjustable needle valve assembly

[0067] The adjustable needle valve assembly is used to regulate the flow rate of the backflow within the electric pump's internal cavity. Based on temperature feedback, it adjusts the flow rate in real time to ensure that the temperature of the hydrogen peroxide within the cavity remains within a safe range. The adjustable needle valve assembly includes an inner screw assembly 240, a rear external sealing ring 250, a rear inner sealing ring 260, a connecting frame 270, a motor screw assembly 280, a linear stepper motor 290, a surface mount resistor 300, and an adjusting needle cone 310.

[0068] The inner screw assembly 240 is used to fix the connecting frame 270.

[0069] The rear external sealing ring is 250mm to prevent fluid leakage.

[0070] The rear internal sealing ring is 260 to prevent fluid medium leakage.

[0071] The connecting frame 270 is used to fix the linear stepper motor 290. It provides a moving hole for the adjusting pin cone 290, which mates with a sealing ring to ensure dynamic sealing of the adjusting pin cone. It also provides mounting holes for the surface mount resistor 300.

[0072] Motor screw assembly 280 is used to fix the linear stepper motor 290.

[0073] Linear stepper motor 290 is used to drive the movement of adjusting pin cone 310. The linear stepper motor used here is an existing product and will not be described in detail. A linear stepper motor is a component that combines a stepper motor and a ball screw into one unit, converting the rotational motion of the stepper motor into the linear motion of the ball screw. Here, the ball screw is fixedly connected to the linear stepper motor 290 and is the extended shaft of the linear stepper motor 290, allowing it to move back and forth.

[0074] A 300Ω surface-mount resistor is used to measure the real-time wall temperature inside the connection frame 270 near the fluid. Due to the strong corrosive and oxidizing properties of hydrogen peroxide, a surface-mount resistor is used to measure the wall temperature in contact with the hydrogen peroxide fluid, approximating the wall temperature of the connection frame 270 as the fluid temperature. Surface-mount resistors offer advantages such as high accuracy, fast response, and easy installation. Four surface-mount resistors are used in this design, evenly distributed on a ring. Their purpose is to average the temperatures measured by the four resistors to obtain a more accurate wall temperature. This also serves as redundancy; if one surface-mount resistor malfunctions, the temperature closed-loop control system can still operate, although the control accuracy will decrease, introducing some steady-state error.

[0075] The adjusting needle cone 310 is used to adjust the flow rate of the return flow within the electric pump's internal cavity. The adjusting needle cone 310 is threadedly connected to the extended shaft of the linear stepper motor 290. The adjusting needle cone 310 and the inner return hole of the rotor core 140 cleverly form an adjustable needle valve. By changing the size of the flow channel area formed between them, the throttling area is changed, thus controlling the return flow rate. Specifically, since the rotor core 140 is a high-speed rotating component, the maximum diameter of the adjusting needle cone 310 is smaller than the inner diameter of the rotor core. It is crucial to avoid friction between the adjusting needle cone 310 and the rotor core 140. If the rotor core 140, rotating at a high speed of 30,000 rpm, rubs against the adjusting needle cone 310, it can easily lead to severe friction, generating heat that could heat hydrogen peroxide, potentially causing a hydrogen peroxide decomposition and explosion.

[0076] IV. Energy Absorption Device Components

[0077] The function of the energy absorption device assembly is to absorb and store energy, converting pressure potential energy into elastic potential energy. It absorbs the impact energy of fluid in the pipeline, preventing water hammer from causing damage to the internal cavity of the electric pump. The energy absorption device assembly includes an energy-absorbing block 370 and an energy-absorbing spring 380.

[0078] The energy-absorbing block 370 serves as the force-bearing surface for fluid impact, bearing and transmitting the instantaneous fluid impact force.

[0079] The energy-absorbing spring 380, as an energy storage element, converts the pressure potential energy of the fluid impact into elastic potential energy, thereby storing the fluid's energy. After being compressed violently in an instant, the energy-absorbing spring 380 slowly returns to its initial compressed position, releasing energy smoothly and preventing the fluid impact from being transmitted to the inner cavity of the electric pump.

[0080] The working process of the energy absorption device is as follows:

[0081] When water hammer occurs, such as during valve opening or closing, instantaneous pressure fluctuations enter the inner cavity through the gap between the impeller 130 and the front cover 330. First, the pressure surge passes through the small space formed by the energy-absorbing block and the impeller. The energy-absorbing block in this space can be compressed and moved backward. A huge impact acts on the surface of the energy-absorbing block 370, causing it to experience a significant acceleration. Since the energy-absorbing spring 380 is connected to the energy-absorbing block, the force from the energy-absorbing block 370 is absorbed by the spring, which rapidly compresses it. Within a short time, the pressure potential energy from the fluid impact is converted into elastic potential energy and stored in the spring 380. After the water hammer subsides, the pressure in the small space formed by the energy-absorbing block and the impeller returns to normal. The energy-absorbing spring 380 slowly releases the elastic potential energy, and the energy-absorbing block 370 returns to its initial position under the action of the spring.

[0082] Example 9

[0083] like Figure 3 The cooling control method for an electric pump using a high-concentration hydrogen peroxide medium, as shown, comprises the following steps:

[0084] ① Obtain the real-time temperature value y(kT) at the current time kT and the target temperature y d The temperature deviation e(k) of (kT), the error value at the current moment, and the temperature change rate Δe(k) at the previous moment;

[0085] ② Fuzzyize the temperature deviation e(k) and the temperature change rate Δe(k) to obtain the corresponding fuzzy output u. e (k) and u Δe (k);

[0086] ③ Adjust the gain coefficient K until there is no overshoot in the temperature response curve;

[0087] ④ Replace the medium with high-concentration hydrogen peroxide and conduct the test.

[0088] Example 10

[0089] Based on Example 9, in step ③, adjusting the gain coefficient K is done by using the dichotomy method to continuously change the output of K, starting the electric pump delivery system, using water as the test medium, and observing the temperature response curve.

[0090] Example 11

[0091] Based on Example 9, in step ②, the controller output is Δx(k) = K(u). e (k)+u Δe (k)).

[0092] Example 12

[0093] Based on the above embodiments, the specific method is as follows:

[0094] Step 1: Obtain the temperature data measured by the chip resistor. Obtain the real-time temperature value y(kT) at the current moment kT and the target temperature y. d The temperature deviation e(k) is given by (kT), the error value at the current moment, and the temperature change rate Δe(k) at the previous moment, where the control period in this paper is T = 0.2s.

[0095] e(k) = y d (kT)-y(kT)

[0096] Δe(k)=e(k)-e(k-1)

[0097] When the initial time k = 1, the initial conditions need to be set, and e(0) = 0 is set. At this time, e(k) = e(1) - e(0) = e(1).

[0098] Step 2: Fuzzification. The temperature deviation e(k) and the rate of temperature change Δe(k) are fuzzified to obtain the corresponding fuzzy output u. e (k) and u Δe (k). In this paper, based on the actual open-loop test temperature rise curve, the temperature deviation e(k) is fuzzified into 7 levels, and the corresponding output u e (k) are -3, -2, -1, 0, 1, 2, 3. The corresponding temperature deviations e(k) are: <-30℃, -30℃ to -20℃, -20℃ to -10℃, -10℃ to 10℃, 10℃ to 20℃, 20℃ to 30℃, >30℃. If the temperature deviation is e(k) = -32℃, then u e (k) = -3. If the temperature deviation is e(k) = -29℃, then u e (k) = -2. If the temperature deviation is e(k) = -12℃, then u e (k) = -1. And so on.

[0099] Based on the actual open-loop test temperature rise curve, the temperature deviation rate of change Δe(k) is fuzzified into 7 levels, with the corresponding output u. Δe(k) are -3, -2, -1, 0, 1, 2, 3. The corresponding temperature deviation rate of change Δe(k) are: <-15℃, -15℃ to -10℃, -10℃ to -5℃, -5℃ to 5℃, 5℃ to 10℃, 10℃ to 15℃, >15℃. If the temperature deviation is e(k) = -16℃, then u e (k) = -3. If the temperature deviation is e(k) = -12℃, then u e (k) = -2. If the temperature deviation is e(k) = -7℃, then u e (k) = -1. And so on.

[0100] Step 2: Fuzzyen the output. The controller output is Δx(k) = K(u) e (k)+u Δe (k)), where K is the gain coefficient, determined based on the temperature response curve during debugging. The specific position of the valve core at time KT is:

[0101] x(k)=Δx(k)+x(k-1)

[0102] Δx(k)=K(u e (k)+u Δe (k))

[0103] Since the position of the needle cone changes, i.e., the change in the position of the needle cone is Δx(k), the change in the fluid flow rate inside the electric pump is ΔQ(k). The change in flow rate ultimately leads to a change in heat exchange, and the temperature of the inner wall of the electric pump changes, thus realizing the entire closed-loop control.

[0104] Step 3: Adjust the gain coefficient K. Using the binary search method, continuously change the output of K, start the electric pump delivery system, use water as the test medium, and observe the temperature response curve until there is no overshoot in the temperature response curve. Then the adjustment of the gain coefficient K is complete.

[0105] Step 4: Replace the medium from water with high-concentration hydrogen peroxide and then conduct the experiment.

[0106] The above method considers both the current temperature deviation e(k) and the rate of change of temperature deviation Δe(k), effectively combining fuzzy control and PD control. It boasts advantages such as simplicity, reliability, and high control accuracy.

[0107] Compared to pure deviation control, the above embodiment has higher control accuracy and a certain degree of predictability because it employs the principles of proportional-derivative control and fuzzy control. For example, if the current temperature deviation e(k) = -35℃, u e (k) = -3. Temperature deviation change rate Δe(k) = 30℃, u Δe (k) = 3. Δx(k) = K(u) e (k)+uΔe When (k)) = 0, the adjusting needle cone does not move. In actual operation, this stage is characterized by a rapid temperature rise. Although the temperature deviation is large, the rate of temperature change is also significant. The needle cone should remain stationary for several cycles until the temperature naturally converges to the set value. If deviation control is used alone at this time, it will lead to actual temperature overshoot, insufficient flow rate, and excessively high hydrogen peroxide temperature, potentially causing danger.

[0108] Therefore, the present invention:

[0109] 1. In the internal structure design of the electric pump, the hydrogen peroxide electric pump is combined with the adjustable needle valve assembly, and the internal fluid temperature of the electric pump is approximately constant through temperature closed-loop control.

[0110] 2. In the cooling control method, the temperature of the high-concentration hydrogen peroxide inside the electric pump is controlled by adjusting the flow rate. Utilizing fuzzy control principles, a simple and reliable cooling control method is proposed. This method requires only simple tuning of the gain coefficient K to achieve the entire closed-loop control, offering advantages such as high control accuracy, ease of implementation, and reliable operation.

[0111] 3. The electric pump employs a spring energy-absorbing device to reduce the impact of instantaneous pressure fluctuations on the pump's internal structure. The main design improvement involves adding an energy-absorbing block and a spring at the pump head. The energy-absorbing block can move back and forth, while the spring is compressed. If, at the moment of valve opening or closing, pressure fluctuations enter the pump through the gap between the impeller and the front cover, the resulting high pressure will push against the energy-absorbing block, further compressing the spring. This converts the pressure potential energy into the spring's elastic potential energy, storing the energy and preventing further transmission of pressure fluctuations to vulnerable parts such as the shielding sleeve. Simultaneously, the energy-absorbing device, consisting of the energy-absorbing block and spring, can also absorb high-frequency pressure fluctuations in the fluid, preventing rapid pressure fluctuations within the pump's internal cavity and further reducing the impact on vulnerable parts such as the shielding sleeve. This solves the safety hazard of the electric pump being subjected to water hammer during valve opening and closing, leading to excessive pressure and shielding sleeve breakage.

Claims

1. An electric pump for high-concentration hydrogen peroxide medium, comprising a stator winding (180) and a stator core (190) constituting the stator, and a rotor magnet (340) and a rotor sheath (350) constituting the rotor, characterized in that: The stator and rotor are encapsulated in a cavity formed by a front cover (330) and a rear cover (320). Liquid flows from the front end to the rear end of the cavity and is in close contact with the rotor. An adjusting needle cone (310) is located at the center of the rear end of the cavity to adjust the liquid flow rate. The adjusting needle cone (310) at the rear end of the rotor is fixed to a linear stepper motor (290). The cone end of the adjusting needle cone (310) cooperates with the return hole in the rotor core (140) of the rotor to form an adjustable needle valve. The maximum diameter of the adjusting needle cone (310) is smaller than the inner diameter of the rotor core (140). The linear stepper motor (290) is used to drive the movement of the adjusting needle cone (310).

2. The electric pump for high-concentration hydrogen peroxide medium as described in claim 1, characterized in that: An impeller (130) is installed at the front end of the rotor, and an inducer (120) is installed at the front end of the impeller (130). The inducer (120) is locked by a locking nut (110). The locking nut (110), the inducer (120), and the impeller (130) are all fixed on the rotor core (140). The front end cover (330) is a volute assembly (100) for liquid to flow into. Between the front end cover (330) and the volute assembly (100), an energy-absorbing block (370) and an energy-absorbing spring (380) are installed to buffer the fluid impact energy.

3. The electric pump for high-concentration hydrogen peroxide medium as described in claim 1, characterized in that: The rotor magnet (340) is fitted inside the rotor sleeve (350), and the rotor sleeve (350) completely isolates the rotor magnet (340) from the liquid inside the cavity.

4. The electric pump for high-concentration hydrogen peroxide medium as described in claim 1, characterized in that: The adjustment needle cone (310) also has a chip resistor (300) fixed on the side of the rear end cover (320). The chip resistor (300) is used to measure the wall temperature in contact with the hydrogen peroxide fluid. There are four chip resistors (300) evenly distributed along the circumference.

5. The electric pump for high-concentration hydrogen peroxide medium as described in claim 1, characterized in that: A shielding sleeve (360) is installed in the cavity directly opposite the rotor magnet (340). The shielding sleeve (360) is equipped with a first sealing ring (200), a second sealing ring (201), a third sealing ring (202), and a fourth sealing ring (203) to isolate the liquid. The shielding sleeve (360) is made of polyetheretherketone.

6. The electric pump for high-concentration hydrogen peroxide medium as described in claim 1, characterized in that: The cooling control method for this electric pump is as follows: ① Obtain the real-time temperature value y(kT) at the current time kT and the target temperature y d The temperature deviation e(k) of (kT), the error value at the current moment, and the temperature change rate Δe(k) at the previous moment; ② Fuzzyize the temperature deviation e(k) and the temperature change rate Δe(k) to obtain the corresponding fuzzy output u. e (k) and u Δe (k); ③ Adjust the gain coefficient K until there is no overshoot in the temperature response curve; ④ Replace the medium with high-concentration hydrogen peroxide and conduct the test.

7. The electric pump for high-concentration hydrogen peroxide medium as described in claim 6, characterized in that: In step ③, adjusting the gain coefficient K involves using the dichotomy method to continuously change the output of K, starting the electric pump delivery system, using water as the test medium, and observing the temperature response curve.

8. The electric pump for high-concentration hydrogen peroxide medium as described in claim 6, characterized in that: In step ②, the controller output is Δx(k) = K(u) e (k)+u Δe (k)).

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