Self-cooling hydrogen peroxide double-head electric pump and starting method thereof

Abstract

This invention provides a self-cooled hydrogen peroxide dual-head electric pump, comprising a stator composed of stator windings and a stator core. The stator has a corresponding rotor within its inner ring. The rotor consists of two coaxial and symmetrical sections, with the centerline between the two sections overlapping the stator centerline. The stator and rotor are housed in a cavity formed by a front end cover and a rear end cover. This cavity allows liquid to enter from the front end of the front rotor section and exit from the rear end of the rear rotor section. The liquid is hydrogen peroxide. This invention also provides a starting method for the self-cooled hydrogen peroxide dual-head electric pump. This invention achieves axial thrust balance in the electric pump through the dual-head design, significantly reducing axial runout and sliding bearing wear. Through the shielding structure design of the electric pump, using shielding sleeves and other structures to separate the stator and rotor, a leak-free function is achieved, thus ensuring applicability to highly corrosive and oxidizing media such as hydrogen peroxide.

Description

Technical Field

[0001] This invention relates to a self-cooled hydrogen peroxide dual-head electric pump and its starting 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 with a concentration exceeding 90%. Commonly used high-concentration hydrogen peroxide concentrations are 90%, 95%, and 98%. Due to its excellent energy properties, high-concentration hydrogen peroxide is often 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. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a self-cooled hydrogen peroxide dual-head electric pump and its starting method. This self-cooled hydrogen peroxide dual-head electric pump and its starting method achieve axial thrust balance in the electric pump through the dual-head design, significantly reducing axial runout and sliding bearing wear. Through the shielding structure design of the electric pump, using shielding sleeves and other structures to separate the stator and rotor, a leak-free function is achieved, thereby ensuring applicability to highly corrosive and oxidizing media such as hydrogen peroxide.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a self-cooled hydrogen peroxide dual-head electric pump, comprising a stator composed of stator windings and a stator core, wherein the stator has a corresponding rotor in the inner ring, the rotor being composed of two sections, the front and rear sections of which are coaxially symmetrical, and the centerline between the two sections overlaps with the centerline of the stator; the stator and rotor are installed in a cavity composed of a front end cover and a rear end cover, the cavity allowing liquid to enter from the front end of the front section of the rotor and exit from the rear end of the rear section of the rotor; the liquid is hydrogen peroxide.

[0008] The front rotor core of the front rotor and the rear rotor core of the rear rotor are connected; the front rotor is rotatably fixed to the front end cover through the front sliding bearing, and the rear rotor is rotatably fixed to the rear end cover through the rear sliding bearing; both the front rotor core and the rear rotor core have multiple channels for recirculation.

[0009] The front rotor and the rear rotor are respectively fixed with front rotor magnets and rear rotor magnets near the center line; the front rotor magnets are enclosed and isolated by the front rotor sheath, and the rear rotor magnets are enclosed and isolated by the rear rotor sheath.

[0010] The front rotor is equipped with a front impeller near its end, and a front inducer is installed at the front end of the front impeller; the rear rotor is equipped with a rear impeller near its end, and a rear inducer is installed at the rear end of the rear impeller.

[0011] The front end of the front idler wheel is locked by a front locking nut, and the rear end of the rear idler wheel is locked by a rear locking nut; a front buffer pad and a front buffer spring provide buffering between the front idler wheel and the front locking nut; a rear buffer pad and a rear buffer spring provide buffering between the rear idler wheel and the rear locking nut.

[0012] The front cover has a front volute assembly at the front end, and the rear cover has a rear volute assembly at the rear end. The front and rear volute assemblies are symmetrical.

[0013] The front end cover has a front energy-absorbing block and a front energy-absorbing spring at its front end position, wherein the front energy-absorbing block can move back and forth, and the front energy-absorbing spring is in a compressed state; the rear end cover has a rear energy-absorbing block and a rear energy-absorbing spring at its rear end position, wherein the rear energy-absorbing block can move back and forth, and the rear energy-absorbing spring is in a compressed state.

[0014] This invention also provides a starting method for a self-cooled hydrogen peroxide dual-head electric pump. The method uses the self-cooled hydrogen peroxide dual-head electric pump described above as the dual-head electric pump, and connects the flow meter, solenoid valve, dual-head electric pump, check valve, solenoid valve, and regulating valve in sequence via pipelines, employing the following steps:

[0015] ① Pre-filling: First, keep the regulating valve at a small opening, then open the solenoid valve and the solenoid valve in sequence until the flow meter reading is stable, then close the solenoid valve and the solenoid valve in sequence.

[0016] ② Refill: Increase the opening of the regulating valve to the set opening, then open the solenoid valve, close the solenoid valve, and open the solenoid valve in sequence to obtain the flow meter reading until the flow meter reading is stable without fluctuation, and then close the solenoid valve and the solenoid valve in sequence.

[0017] ③ Trial run: Keep the solenoid valve and the solenoid valve closed, set the target speed of the dual-head electric pump and start it. If the pressure is stable after starting the dual-head electric pump, proceed to the next step; otherwise, return to the previous step.

[0018] ④ Normal operation: Turn on the solenoid valve, solenoid valve and dual-head electric pump in sequence.

[0019] The target speed of the dual-head electric pump is 40,000 rpm.

[0020] In steps ① and ②, the rotational speed of the dual-head electric pump is 5000 rpm.

[0021] The beneficial effects of this invention are as follows: axial thrust balance of the electric pump is achieved through the dual-head electric pump, greatly reducing axial runout and sliding bearing wear; the shielded structure design of the electric pump, using shielding sleeves and other structures to separate the stator and rotor, achieves a leak-free function, thus ensuring applicability to highly corrosive and oxidizing media such as hydrogen peroxide; the internal dual-reflux design of the electric pump achieves self-circulating cooling of the dual-head pump, reducing the temperature of the high-speed motor through media circulation cooling, reducing the need for heat dissipation devices, and increasing the compactness of the structure and space utilization. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of at least one embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Enlarged schematic diagram of the position of the front volute assembly;

[0024] Figure 3 yes Figure 1 Schematic diagram of the external structure;

[0025] Figure 4 This is a connection diagram of at least one embodiment of the present invention.

[0026] In the diagram: 1-Flow meter, 2-Solenoid valve, 3-Dual-head electric pump, 4-Check valve, 5-Solenoid valve, 6-Regulating valve, 100-Front volute assembly, 200-Rear volute assembly, 101-Front inducer, 201-Rear inducer, 102-Front impeller, 202-Rear impeller, 110-Front locking nut, 111-Front buffer gasket, 112-Front buffer spring, 210-Rear locking nut, 211-Rear buffer gasket, 212-Rear buffer spring, 120-Front rotor core, 220-Rear rotor core, 240-Rear rotor core, 130-Front screw assembly, 230-Rear screw assembly, 140-Front inner seal ring, 14 1-Front outer sealing ring, 240-Rear inner sealing ring, 241-Rear outer sealing ring, 150-Front sliding bearing, 250-Rear sliding bearing, 160-First sealing ring, 161-Second sealing ring, 260-Third sealing ring, 261-Fourth sealing ring, 170-Front rotor magnet, 270-Rear rotor magnet, 171-Front rotor sheath, 271-Rear rotor sheath, 180-Front energy-absorbing block, 181-Front energy-absorbing spring, 280-Rear energy-absorbing block, 281-Rear energy-absorbing spring, 290-Shielding sleeve, 300-Stator winding, 301-Stator core, 310-Front end cover, 320-Rear end cover, 330-Screw assembly. 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 Figures 1 to 3 The self-cooled hydrogen peroxide dual-head electric pump shown includes a stator composed of a stator winding 300 and a stator core 301. The stator has a corresponding rotor in its inner ring. The rotor is composed of two sections, front and rear, which are coaxial and symmetrical. The centerline between the two sections overlaps with the centerline of the stator. The stator and rotor are installed in a cavity composed of a front cover 310 and a rear cover 320. Liquid can enter from the front end of the front rotor and exit from the rear end of the rear rotor. The liquid is hydrogen peroxide.

[0030] Example 2

[0031] Based on Embodiment 1, the front rotor core 120 of the front rotor and the rear rotor core 220 of the rear rotor are connected; the front rotor is rotatably fixed to the front end cover 310 through the front sliding bearing 150, and the rear rotor is rotatably fixed to the rear end cover 320 through the rear sliding bearing 250; both the front rotor core 120 and the rear rotor core 240 have multiple channels for recirculation.

[0032] Example 3

[0033] Based on Embodiment 1, the front rotor and the rear rotor are respectively fixed with a front rotor magnet 170 and a rear rotor magnet 270 at the position near the center line; the front rotor magnet 170 is enclosed and isolated by the front rotor sleeve 171, and the rear rotor magnet 270 is enclosed and isolated by the rear rotor sleeve 271.

[0034] Example 4

[0035] Based on Embodiment 1, a front impeller 102 is installed near the end of the front rotor, and a front inducer 101 is installed at the front end of the front impeller 102; a rear impeller 202 is installed near the end of the rear rotor, and a rear inducer 201 is installed at the rear end of the rear impeller 202.

[0036] Example 5

[0037] Based on Embodiment 4, the front end of the front guide wheel 101 is locked by the front locking nut 110, and the rear end of the rear guide wheel 201 is locked by the rear locking nut 210; a front buffer pad 111 and a front buffer spring 112 provide buffering between the front guide wheel 101 and the front locking nut 110; a rear buffer pad 211 and a rear buffer spring 212 provide buffering between the rear guide wheel 201 and the rear locking nut 210.

[0038] Example 6

[0039] Based on Embodiment 1, the front end cover 310 has a front volute assembly 100 at the front end, and the rear end cover 320 has a rear volute assembly 200 at the rear end. The front volute assembly 100 and the rear volute assembly 200 are symmetrical.

[0040] Example 7

[0041] Based on Embodiment 1, the front end cover 310 has a front energy-absorbing block 180 and a front energy-absorbing spring 181 at its front end position, wherein the front energy-absorbing block 180 can move back and forth, and the front energy-absorbing spring 181 is in a compressed state; the rear end cover 320 has a rear energy-absorbing block 280 and a rear energy-absorbing spring 281 at its rear end position, wherein the rear energy-absorbing block 280 can move back and forth, and the rear energy-absorbing spring 281 is in a compressed state.

[0042] Example 8

[0043] Based on the above embodiments, the system comprises four parts: a dual-head centrifugal pump assembly, a high-speed motor assembly, an energy absorption device, and a buffer device assembly. The centrifugal pump assembly pressurizes the fluid. The high-speed motor assembly primarily drives the impeller, which is fixedly connected to the rotor, to rotate at high speed. The energy absorption device 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 internal cavity of the electric pump. The buffer device buffers the fluid, preventing upstream fluid from directly entering the cooling circulation cavity of the electric pump and causing damage during valve opening.

[0044] I. Centrifugal Pump Assembly

[0045] The centrifugal pump assembly includes a front volute assembly 100, a front inducer 101, a front impeller 102, and a front locking nut 110. Being a dual-head centrifugal pump, it also includes a rear volute assembly 200, a rear inducer 201, a rear impeller 202, and a rear locking nut 210.

[0046] Front volute assembly 100 and rear volute assembly 200. These serve as the housing, inlet, and outlet of the centrifugal pump.

[0047] The front inducer 101 and the rear inducer 201 can entrain the fluid medium, thereby increasing the static pressure of the fluid and reducing the static positive suction pressure of the centrifugal pump by entraining the fluid into the impeller.

[0048] The front impeller 102 and the rear impeller 202. The medium enters through the axial channel of the front impeller 102 and the rear impeller 202, and the medium is thrown out radially. By doing work on the fluid through centrifugal force, the low-pressure fluid is converted into a high-pressure fluid, thereby increasing the fluid pressure.

[0049] The front locking nut 110 and the rear locking nut 210 serve two purposes. First, they fix the inducer and impeller to the front rotor core 120. The front locking nut 100 is threadedly connected to the front rotor core 120. Second, they act as limiting devices to restrict the movement of the front buffer pad 111 and the front buffer spring 112.

[0050] II. High-speed motor assembly

[0051] The high-speed motor assembly includes a front rotor core 120, a rear rotor core 220, a front screw assembly 130, a rear screw assembly 230, a front inner seal ring 140, a front outer seal ring 141, a rear inner seal ring 240, a rear outer seal ring 241, a front sliding bearing 150, a rear sliding bearing 250, a first seal ring 160, a second seal ring 161, a third seal ring 260, a fourth seal ring 261, a front rotor magnet 170, a rear rotor magnet 270, a front rotor sheath 171, a rear rotor sheath 271, a shielding sleeve 290, a stator winding 300, a stator core 301, a front end cover 310, a rear end cover 320, a screw assembly 330, and a colloid filled between the motor stator and the housing. This colloid is used to fill the gaps around the stator to achieve stator reinforcement and stability.

[0052] The front rotor core 120 and the rear rotor core 220 are integrally machined structures. The rotor is divided into two parts, namely the front rotor core 120 and the rear rotor core 220, which present a symmetrical structure. The rotor has internal through holes, and 12 channels are opened in the middle of the rotor for reflux. The function of these 12 channels is to guide the fluid inside the shielding sleeve into the central reflux hole inside the rotor. The reflux channel returns the hydrogen peroxide medium entering from the 12 channels in the middle of the rotor to the front end of the inducer, and finally leads it out from the inducer to the upstream of the electric pump.

[0053] Front screw assembly 130 and rear screw assembly 230. Front screw assembly 130 is used to secure the front volute assembly 100 and the front end cover 310; rear screw assembly 230 is used to secure the rear volute assembly 200 and the rear end cover 320.

[0054] The front inner sealing ring 140, the front outer sealing ring 141, the rear inner sealing ring 240, and the rear outer sealing ring 241 are used for sealing to prevent leakage of liquid medium inside the electric pump.

[0055] A front sliding bearing 150 and a rear sliding bearing 250 are provided. The front sliding bearing 150 supports the front rotor core 120 and serves as a connector between the front rotor core 120 and the front end cover 310, reducing the frictional resistance experienced by the front rotor core 120. The rear sliding bearing 250 supports the rear rotor core 220 and serves as a connector between the rear rotor core 220 and the rear end cover 320, reducing the frictional resistance experienced by the rear rotor core 220.

[0056] The first sealing ring 160, the second sealing ring 161, the third sealing ring 260, and the fourth sealing ring 261 are used for sealing to prevent leakage of liquid medium in the return channel of the electric pump, and to prevent hydrogen peroxide from reacting with the stator winding 300 and the potting colloid around the stator through the shielding sleeve.

[0057] The front rotor magnet 170 and the rear rotor magnet 270 provide torque under the electromagnetic influence generated by the stator. The front rotor magnet 170, made of neodymium iron boron, is divided into two semicircles and is attached to the front rotor core 120, isolated from the internal circulating medium peroxide component by the front rotor sleeve 171. The rear rotor magnet 270, also made of neodymium iron boron, is divided into two semicircles and is attached to the rear rotor core 220, isolated from the internal circulating medium peroxide component by the rear rotor sleeve 271.

[0058] The front rotor sheath 171 and the rear rotor sheath 271 are connected to the front rotor core 120 and the rear rotor core 220 by welding. Their function is to protect the front rotor magnet 170 and the rear rotor magnet 270 and prevent the hydrogen peroxide inside the motor from coming into contact with the front rotor magnet 170 and the rear rotor magnet 270 and reacting with them.

[0059] The shielding sleeve 290 serves three purposes. First, it is made of polyetheretherketone (PEEK), a non-metallic material. The non-metallic nature of PEEK reduces high-frequency eddy current losses, prevents power loss, and eliminates ineffective heat generation from the shielding sleeve. Second, the high strength of PEEK ensures that the shielding sleeve 290 can withstand high internal pressure, preventing it from rupturing due to excessive pressure. Third, in conjunction with the first sealing ring 160, the second sealing ring 161, the third sealing ring 260, and the fourth sealing ring 261, it isolates the stator from the internal fluids of the motor, preventing them from contacting and reacting.

[0060] The stator winding 300 and the stator core 301 together form the stator, which is used to introduce three-phase AC to generate a rotating magnetic field, thereby driving the front rotor core 120 and the rear rotor core 220 to rotate at high speed.

[0061] Front cover 310. It has a fixed base structure for fixing the entire motor to the frame. It fixes the front volute assembly 100, limits the buffer pad 111 and buffer spring 112 of the buffer device, provides support for the sliding bearing 150, and limits the shielding sleeve 290, etc., for mechanical positioning and installation purposes.

[0062] The rear end cover 320 fixes the volute assembly 200, which limits the rear buffer pad 211 and rear buffer spring 212 of the buffer device, provides support for the sliding bearing 250, and limits the shielding sleeve 290, etc., for mechanical positioning and installation.

[0063] Screw assembly 330. Secures the front end cover 310 and the rear end cover 320.

[0064] The potting compound is used to fill the gaps inside the motor stator, thereby further securing the stator and preventing it from loosening.

[0065] III. Energy Absorption Device Components

[0066] 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 a front energy absorption block 180, a front energy absorption spring 181, a rear energy absorption block 280, and a rear energy absorption spring 281.

[0067] The front energy-absorbing block 180 and the rear energy-absorbing block 280 serve as the force-bearing surfaces for fluid impact, bearing and transmitting the instantaneous fluid impact force.

[0068] The front energy-absorbing spring 181 and the rear energy-absorbing spring 281, as energy storage elements, convert 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 front energy-absorbing spring 181 and the rear energy-absorbing spring 281 slowly return to their initial compressed positions, gently releasing the energy and preventing the fluid impact from being transmitted to the inner cavity of the electric pump.

[0069] Taking the front energy-absorbing block 180 and the front energy-absorbing spring 181 as examples, the working process of the energy-absorbing device is as follows:

[0070] When water hammer occurs, such as during valve opening or closing, instantaneous pressure fluctuations enter the inner cavity through the gap between the front impeller 102 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 front energy-absorbing block 180, causing it to experience a significant acceleration. Since the front energy-absorbing spring 181 is connected to the back of the energy-absorbing block, the force from the front energy-absorbing block 180 is absorbed by the spring, which is rapidly compressed. Within a short time, the pressure potential energy from the fluid impact is converted into elastic potential energy and stored in the spring. After the water hammer subsides, the pressure in the small space formed by the energy-absorbing block and the impeller returns to normal. The front energy-absorbing spring 181 slowly releases the elastic potential energy, and the front energy-absorbing block 180 returns to its initial position under the action of the spring.

[0071] IV. Buffer Device

[0072] The buffer device buffers the fluid, preventing upstream fluid from directly entering the cooling circulation chamber of the electric pump and causing damage during the valve opening process. The buffer device assembly includes a front buffer pad 111, a front buffer spring 112, a rear buffer pad 211, and a rear buffer spring 212.

[0073] The front buffer pad 111 and the rear buffer pad 211 bear the buffering force of the fluid and transmit the force to the front buffer spring 112 and the rear buffer spring 212.

[0074] The front buffer spring 112 absorbs the impact force of the stored filling fluid, compresses rapidly and then slowly recovers, releasing the force gradually.

[0075] Taking the front buffer pad 111 and the front buffer spring 112 as examples, the working process of the buffer device is as follows:

[0076] When the upstream valve of the electric pump is opened, water hammer will occur during the liquid filling process because there is no accumulated liquid inside or downstream of the electric pump. This is visually manifested as upstream liquid flowing along the pipe, impacting the inducer wheel, and some liquid passing through the return hole in the center of the inducer wheel, rushing into the inner cavity of the electric pump at high speed, causing some damage to the pump's internal structure.

[0077] To prevent water hammer from damaging the inner cavity of the electric pump during valve opening, a buffer device was added at the return outlet of the inducer in this case, which can effectively reduce the water hammer caused by valve opening and filling.

[0078] The buffer pad has a small hole in the center, which has a throttling effect. This ensures that during filling, the fluid enters the return chamber through the small hole of the front buffer pad 111 from the axial direction, and slowly fills the inner cavity of the electric pump with a small flow rate.

[0079] The buffer pad can also buffer the high-speed fluid filling after the valve is opened. When the filling fluid reaches the inducer after the valve is opened, it will impact the front buffer pad 111. The buffer pad will transmit the force to the buffer spring, and the buffer spring will be compressed quickly. Through this buffering process, the fluid speed entering the inner cavity of the electric pump is slowed down.

[0080] The front locking nut 110 has four evenly spaced grooves on its side. These grooves can accelerate the filling process and increase the filling speed of the electric pump's internal cavity. Since the four grooves of the front locking nut 110 are located on the side and perpendicular to the velocity of the filling fluid, the fluid entering the electric pump's internal cavity from this direction has a slower velocity and will not cause a strong impact on the electric pump's internal cavity.

[0081] In summary, during valve opening and filling, there are two paths for the fluid to enter the inner cavity from the central return hole of the front rotor core 120. The first path is through the central throttling hole of the buffer pad. After the throttling effect of the throttling hole, the flow velocity of this part of the fluid slows down, and the impact is greatly reduced. The second path is through the four grooves on the side of the front locking nut 110 to enter the return hole. The direction of this path is perpendicular to the fluid filling flow direction. There is no initial flow velocity in the vertical direction, and the impact on the electric pump is small. Therefore, the buffer device greatly reduces the impact and loss on the inner cavity of the electric pump during the filling process.

[0082] At the same time, the buffer device can increase the efficiency of the electric pump. The mechanism of action is as follows:

[0083] Without a buffer device, during normal operation of the electric pump, the circulating cooling fluid in the inner cavity will be axially ejected through the axial hole of the front rotor core 120. The return fluid flows in the opposite direction to the inlet fluid of the electric pump. Due to viscous shearing, this part of the return flow will reduce the flow velocity of the inlet fluid of the electric pump, consuming some of the fluid's kinetic energy. Because the fluid enters the inducer at a reduced velocity, the entrainment effect of the inducer and the impeller pressurization effect will be reduced, thus affecting the overall efficiency of the electric pump.

[0084] This case study improves the overall efficiency of the electric pump by changing the ejection direction of the return flow, thus avoiding the opposing effect between the return flow and the inlet flow of the electric pump. During normal operation of the electric pump, the return fluid passes through a buffer device and merges with the main flow at the pump inlet via two paths. The first path exits through the central hole of the buffer gasket. Due to the small diameter of the central hole, it has a strong throttling effect, and the flow rate in this path is negligible. The second path merges with the main flow through the four channels on the side of the locking nut. Since the four channels have no throttling effect and a large channel area, the main flow of the return flow passes through this path. The ejection direction of this path is perpendicular to the main flow direction at the pump inlet, thus avoiding loss of the main flow's kinetic energy. This enhances the entrainment effect of the inducer, increases the impeller inlet pressure, and improves the overall efficiency of the electric pump.

[0085] Example 9

[0086] like Figure 4 The method for starting a self-cooled hydrogen peroxide dual-head electric pump, as shown above, uses the self-cooled hydrogen peroxide dual-head electric pump as the dual-head electric pump 3. The flow meter 1, solenoid valve 2, dual-head electric pump 3, check valve 4, solenoid valve 5, and regulating valve 6 are connected in sequence via pipelines, and the following steps are followed:

[0087] ① Pre-filling: First, keep the regulating valve 6 at a small opening, then open the solenoid valve 5 and solenoid valve 2 in sequence until the reading of the flow meter 1 is stable, and then close the solenoid valve 5 and solenoid valve 2 in sequence.

[0088] ② Refill: Increase the opening of regulating valve 6 to the set opening, then open solenoid valve 2, close solenoid valve 5, and open solenoid valve 5 in sequence to obtain the reading of flow meter 1 until the reading of flow meter 1 is stable and without fluctuation, and then close solenoid valve 5 and solenoid valve 2 in sequence.

[0089] ③ Trial run: Keep solenoid valves 5 and 2 closed, set the target speed of the dual-head electric pump 3 and start it. If the pressure is stable after starting the dual-head electric pump 3, proceed to the next step; otherwise, return to the previous step.

[0090] ④ Normal operation: Open solenoid valve 2, solenoid valve 5 and dual-head electric pump 3 in sequence.

[0091] Example 10

[0092] Based on Example 9, the target rotational speed of the dual-head electric pump 3 is 40,000 rpm.

[0093] Example 11

[0094] Based on Example 9, in steps ① and ②, the rotational speed of the dual-head electric pump 3 is 5000 rpm.

[0095] Example 12

[0096] Based on the above embodiments, the two centrifugal pumps of the electric pump must be filled in place and start synchronously. Otherwise, partial filling will result in one centrifugal pump having a large flow rate, large axial thrust, and large starting torque, while the other centrifugal pump has a small flow rate, small axial thrust, and small starting torque. This will cause uneven force on both ends of the high-speed motor, preventing the high-speed motor from working properly and resulting in start-up failure.

[0097] The components of the conveying system are: flow meter 1, solenoid valve 2, double-headed electric pump 3, check valve 4, solenoid valve 5, and regulating valve 6.

[0098] Flowmeter 1 monitors the flow rate in real time, primarily using the stability of the flow curve to determine the filling degree and effect. The electric pump can only be started after the flow curve has stabilized without fluctuations.

[0099] Solenoid valve 2 is the upstream control valve of the electric pump, which controls the filling sequence of the dual-head electric pump.

[0100] The dual-head electric pump 3 performs work on the fluid, using centrifugal force to increase the fluid's kinetic energy, and then uses a gradually expanding pipe to convert the fluid's kinetic energy into fluid pressure potential energy, thereby pressurizing the fluid.

[0101] The one-way valve 4 reduces the impact of liquid backflow and water hammer on the dual-head electric pump 3 when the valve is closed, by avoiding reverse flow of fluid.

[0102] Solenoid valve 5 is a control valve downstream of the electric pump, used to control the filling process of fluid and the opening and closing of the delivery system.

[0103] The regulating valve 6 adjusts the flow rate in the pipeline by changing the minimum flow area. It works in conjunction with an electric pump to change the flow rate of the delivery system in real time.

[0104] The specific work process is as follows:

[0105] Step 1: Pre-filling. Pre-fill a portion of the pipeline with a small flow rate for initial filling. First, reduce the opening of regulating valve 6. Maintaining a small opening of regulating valve 6 provides a strong throttling effect, ensuring a low system flow rate and avoiding the impact of large flow rates, as a lower flow rate results in a weaker filling impact. However, excessively low flow rates will lead to prolonged filling time. Second, sequentially open solenoid valves 5 and 2. Fluid fills the entire pipeline. Finally, observe the flow curve until it stabilizes at a low flow rate, then sequentially close solenoid valves 5 and 2. The dual-head electric pump pre-filling is complete. At this point, due to the low upstream pressure and flow rate, some internal surface areas of the pipeline remain unwetted, and unexpelled gas may be trapped inside.

[0106] Step 2: Refilling. Refill at a higher flow rate for complete filling. First, increase the opening of regulating valve 6 to the set opening. With a larger opening of regulating valve 6, the throttling effect is reduced, increasing the system flow. Since there is already fluid inside the dual-head electric pump, the water hammer effect during refilling is weak. Second, open solenoid valve 2 and close solenoid valve 5, then start the electric pump and maintain low-speed operation. Set the electric pump speed to a low speed, such as 5000 rpm. Finally, open solenoid valve 5, keep solenoid valve 2 open, and maintain low-speed operation of the electric pump. Observe the flow meter reading; once the flow reading stabilizes without fluctuation, refilling is complete, and solenoid valves 5 and 2 are closed sequentially. During the refilling stage, the electric pump rotates at low speed, increasing the downstream pressure and flow rate, further wetting the inner cavity of the electric pump, and further filling the downstream pipeline.

[0107] Step 3: Trial run to assess filling effect. First, keep solenoid valves 5 and 2 closed, and change and set the electric pump speed. Set the electric pump to the target speed, such as changing it from 5000 rpm to 40000 rpm. Second, start the electric pump and observe the pressure after pumping. If the pressure after pumping is stable and without abnormalities, it indicates that the pipeline filling is complete; otherwise, return to step 2. Finally, if the pressure after pumping remains stable and the pressure curve is smooth without fluctuations, proceed to the next step.

[0108] Step 3: Normal Operation. At this point, open solenoid valve 2, solenoid valve 5, and the electric pump in sequence. The electric pump will operate at the set speed of 40,000 rpm. Since there is no abnormal pressure after the pump, open solenoid valve 5, and the system will operate normally. The start-up process of the dual-head electric pump is now complete.

[0109] Therefore, the present invention:

[0110] 1. Based on the internal structure design of the electric pump, hydrogen peroxide is introduced into the inner cavity of the electric pump and circulated for cooling.

[0111] 2. A dual-head electric pump is adopted, with two shafts drawn from a high-speed motor and symmetrically arranged as centrifugal pump components. The forces at both ends are consistent, thereby balancing the axial thrust of the electric pump.

[0112] 3. A spring energy-absorbing device and a buffer device are adopted to reduce the impact of instantaneous pressure fluctuations on the internal structure of the electric pump; an energy-absorbing device, such as an energy-absorbing block and an energy-absorbing spring, is added at the pump head; a buffer device, such as a buffer pad and a buffer spring, is added at the inlet of the inducer wheel; these measures prevent rapid fluctuations in the internal pressure of the electric pump, further reduce the impact on weak parts such as the shielding sleeve, and solve the safety hazard of the electric pump being subjected to water hammer from valve switching, which could lead to excessive pressure and breakage of the shielding sleeve.

Claims

1. A method of starting a self-cooled hydrogen peroxide double-headed electric pump, characterized in that: A dual-head electric pump (3) is used, and the flow meter (1), the first solenoid valve (2), the dual-head electric pump (3), the check valve (4), the second solenoid valve (5), and the regulating valve (6) are connected in sequence through pipelines, using the following steps: ① Pre-filling: First, keep the regulating valve (6) at a small opening, then open the second solenoid valve (5) and the first solenoid valve (2) in sequence until the reading of the flow meter (1) is stable, then close the second solenoid valve (5) and the first solenoid valve (2) in sequence. ② Refill: Increase the opening of the regulating valve (6) to the set opening, open the first solenoid valve (2) in sequence, close the second solenoid valve (5), open the second solenoid valve (5) in sequence, obtain the reading of the flow meter (1) until the reading of the flow meter (1) is stable and without fluctuation, and close the second solenoid valve (5) and the first solenoid valve (2) in sequence. ③ Trial run: Keep the second solenoid valve (5) and the first solenoid valve (2) closed, set the target speed of the double-headed electric pump (3) and start it. If the pressure is stable after starting the double-headed electric pump (3), proceed to the next step; otherwise, return to the previous step. ④ Normal operation: Open the first solenoid valve (2), the second solenoid valve (5) and the dual-head electric pump (3) in sequence.

2. The method of starting a self-cooling hydrogen peroxide double-headed electric pump according to claim 1, characterized in that: The target speed of the dual-head electric pump (3) is 40,000 rpm.

3. The method of starting a self-cooling hydrogen peroxide double-headed electric pump according to claim 1, characterized in that: In steps ① and ②, the rotational speed of the dual-head electric pump (3) is 5000 rpm.

4. A self-cooling hydrogen peroxide double-head electric pump applied to the starting method in any one of claims 1-3, characterized in that: The self-cooled hydrogen peroxide dual-head electric pump includes a stator composed of a stator winding (300) and a stator core (301). The stator inner ring has a corresponding rotor, which is composed of two sections, front and rear, and the two sections are coaxially symmetrical, with the center line between the two sections overlapping the center line of the stator. The stator and rotor are installed in a cavity composed of a front end cover (310) and a rear end cover (320). The cavity allows liquid to enter from the front end of the front section of the rotor and exit from the rear end of the rear section of the rotor. The liquid is hydrogen peroxide.

5. The self-cooling peroxide double-headed electric pump according to claim 4, characterized in that: The front rotor core (120) of the front rotor and the rear rotor core (220) of the rear rotor are connected; the front rotor is rotatably fixed to the front end cover (310) through the front sliding bearing (150), and the rear rotor is rotatably fixed to the rear end cover (320) through the rear sliding bearing (250); both the front rotor core (120) and the rear rotor core have multiple channels for recirculation.

6. The self-cooling peroxide double-headed electric pump according to claim 4, characterized in that: The front rotor and the rear rotor are respectively fixed with front rotor magnet (170) and rear rotor magnet (270) near the center line; the front rotor magnet (170) is enclosed and isolated by the front rotor sleeve (171), and the rear rotor magnet (270) is enclosed and isolated by the rear rotor sleeve (271).

7. The self-cooling peroxide double-headed electric pump according to claim 4, characterized in that: The front rotor is equipped with a front impeller (102) near its end, and a front inducer (101) is installed at the front end of the front impeller (102); the rear rotor is equipped with a rear impeller (202) near its end, and a rear inducer (201) is installed at the rear end of the rear impeller (202).

8. The self-cooling peroxide double-headed electric pump according to claim 7, characterized in that: The front end of the front guide wheel (101) is locked by the front locking nut (110), and the rear end of the rear guide wheel (201) is locked by the rear locking nut (210). A front buffer pad (111) and a front buffer spring (112) provide buffering between the front guide wheel (101) and the front locking nut (110). A rear buffer pad (211) and a rear buffer spring (212) provide buffering between the rear guide wheel (201) and the rear locking nut (210).

9. The self-cooling peroxide double-headed electric pump according to claim 4, characterized in that: The front cover (310) has a front volute assembly (100) at the front end, and the rear cover (320) has a rear volute assembly (200) at the rear end. The front volute assembly (100) and the rear volute assembly (200) are symmetrical.

10. The self-cooling peroxide double-headed electric pump according to claim 4, characterized in that: The front end cover (310) has a front energy-absorbing block (180) and a front energy-absorbing spring (181) at its front end position, wherein the front energy-absorbing block (180) can move back and forth, and the front energy-absorbing spring (181) is in a compressed state; the rear end cover (320) has a rear energy-absorbing block (280) and a rear energy-absorbing spring (281) at its rear end position, wherein the rear energy-absorbing block (280) can move back and forth, and the rear energy-absorbing spring (281) is in a compressed state.

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