A magnetic drive pump system having a flush assembly

Abstract

The utility model relates to the field of magnetic force pump sealing, especially a magnetic force pump system with a flushing assembly, including magnetic force pump, magnetic force pump has the pump body, the isolating bushing, still include: water inlet hole, open in the pump body, flush pipeline is connected with water inlet hole, baffle is fixedly connected with the end of isolating bushing, first backflow hole, second backflow hole, both open in the baffle, balance bushing is sleeved in the pump shaft of magnetic force pump, the pump body is provided with the flow channel of the water inlet hole and first backflow hole, second backflow hole intercommunication, the utility model has the following beneficial effect: adopt external flushing liquid and pump internal structure change, no matter the device opens the parking process or the process material feeding mistake process, the equipment will not burn because of medium with crystalline particle, and retains the original magnetic force pump leakproof advantage, will not cause the scene safety hidden danger because of machine seal leakage.

Description

Technical Field

[0001] This utility model relates to the field of magnetic pump sealing, and in particular to a magnetic pump system with a flushing component. Background Technology

[0002] A magnetic drive pump consists of three core components: the pump itself, the magnetic drive mechanism, and the electric motor. Its unique feature lies in the magnetic drive mechanism, which comprises an outer magnetic rotor, an inner magnetic rotor, and a non-magnetic isolation sleeve. When the electric motor starts and drives the outer magnetic rotor to rotate, its magnetic field easily penetrates the air gap and non-magnetic materials, thereby driving the inner magnetic rotor, connected to the impeller, to rotate synchronously. This design achieves contactless power transmission, transforming components that previously required dynamic seals into static seals, significantly improving sealing performance. Because the shielded sealing cavity system composed of the flow-through components of the magnetic drive pump lacks dynamic seals, it ensures zero leakage and zero contamination.

[0003] A certain chemical plant currently uses magnetic pumps such as Figure 1 As shown, the impeller has an impeller outlet for the medium to enter and exit, and the pump body has a flow channel for the medium to enter the isolation sleeve. When the pump is working, the impeller generates a suction force, which draws the medium in from the inlet of the magnetic pump and discharges it from the outlet. A portion of the medium will enter the flow channel through the impeller outlet and then enter the isolation sleeve to lubricate and cool components such as sliding bearings.

[0004] The medium used in the PO separation unit of the propylene oxide plant is C3H6O, a colorless liquid and an organic compound with strong oxidizing properties. It decomposes easily at high temperatures and is classified as a Group 2B carcinogen. Therefore, any leakage is strictly prohibited during the transport of propylene oxide, making a magnetic drive pump an optimal solution. During normal operation, the PO separation process in the propylene oxide plant produces a clean liquid. However, in the early stages of production, the system needs to be balanced with acids and bases. Excess sulfate ions will react with the separated byproducts to form sulfate crystals.

[0005] First, as solid particles, the irregularity and density differences of the crystals can lead to unstable fluid flow, causing vibration of the magnetic pump rotor, affecting its stable operation, and even causing damage. Second, these particles may wear down the internal components of the magnetic pump, accelerating equipment aging and shortening its service life. When the magnetic pump is working, the outer sleeve of the sliding bearing is stationary, while the inner sleeve rotates synchronously with the pump shaft, impeller, and internal magnet. The pumped medium, under the pressure generated by the impeller rotation, lubricates and cools the sliding bearing through the flow channels within the pump body. Because the sliding bearing is mostly made of pressureless sintered silicon carbide, which has high hardness, good wear resistance, and can withstand temperatures up to 1800℃, it relies on the medium itself for cooling and lubrication. Its disadvantages are that it is very brittle and cannot withstand dry grinding. This dictates that the medium pumped by the magnetic pump cannot contain particles. If particles are present between the inner and outer sleeves of the sliding bearing, after the pump starts operating, the inner and outer sleeves will rotate relative to each other within a short time, leading to bearing breakage and damage. Furthermore, the magnetic pump must have a medium to lubricate the sliding bearing during operation to prevent the inner and outer sleeves from dry grinding into powder.

[0006] In summary, the crystals produced in the early stages of propylene oxide production may cause pumps and machinery to burn out. Therefore, to ensure stable operation and equipment safety, relevant system modifications are crucial. Utility Model Content

[0007] The purpose of this invention is to provide a magnetic pump system with a rinsing component, which can rinse crystals and ensure long-term operation of the device.

[0008] The above-mentioned technical objective of this utility model is achieved through the following technical solution: a magnetic pump system with a flushing assembly, comprising a magnetic pump, the magnetic pump having a pump body and an isolation sleeve, and further comprising:

[0009] The water inlet is located on the pump body;

[0010] The flushing line is connected to the water inlet.

[0011] The partition is fixedly connected to the end of the isolation sleeve;

[0012] The first reflux hole and the second reflux hole are both located on the partition plate;

[0013] A balancing sleeve is fitted onto the pump shaft of the magnetic pump;

[0014] The pump body has a flow channel that connects the water inlet hole with the first return hole and the second return hole.

[0015] Preferably, the water inlet is equipped with an O-ring.

[0016] Preferably, the water inlet is equipped with a pipeline interface, and the flushing pipeline is connected to the water inlet through the pipeline interface.

[0017] Preferably, a pressure reducing valve is installed on the flushing line.

[0018] As a preferred option, a pressure gauge is installed on the flushing line.

[0019] Preferably, an orifice plate is installed on the flushing pipeline, and a flange is connected to the flushing pipeline, with the orifice plate disposed in the flange.

[0020] Preferably, the inner diameter of the first reflux hole and the second reflux hole is 12 mm.

[0021] Preferably, the thickness of the balancing sleeve is 3mm.

[0022] In summary, this utility model has the following beneficial effects:

[0023] This utility model adopts an external flushing fluid and a modified internal pump structure. Regardless of the start-up or shutdown of the device or the process feeding error, the equipment will not be burned due to the medium carrying crystal particles. It also retains the original magnetic pump's leak-free advantage and will not cause on-site safety hazards due to mechanical seal leakage. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an existing magnetic pump in the background art;

[0025] Figure 2 This is a schematic diagram of the overall structure of the embodiment;

[0026] Figure 3 This is a schematic diagram of the magnetic pump in the embodiment;

[0027] Figure 4 This is a schematic diagram of the pipeline interface in the embodiment;

[0028] Figure 5 This is a schematic diagram of the structure of the partition and the isolation sleeve in the embodiment;

[0029] Figure 6 This is a schematic diagram of the balancing sleeve in the embodiment.

[0030] In the diagram, 1. Magnetic pump; 11. Pump body; 12. Isolation sleeve; 13. Water inlet; 14. Baffle plate; 15. First reflux hole; 16. Second reflux hole; 17. Balance sleeve; 18. Pipeline interface; 2. Flushing pipeline; 3. Pressure reducing valve; 4. Pressure gauge; 5. Orifice plate. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings.

[0032] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0033] Example:

[0034] In this embodiment, the propylene oxide feed pump that is shut down on-site is a single-stage magnetic pump, model CHPM100-400. Two pumps are in operation on-site, with one as a backup. The pump operates at an inlet pressure of 0.17MPa and an outlet pressure of 1.74MPa. The medium is PO, methanol, and water. The shaft power is 178.9KW, and the motor power is 200KW. It can be seen that the axial force of the pump is not small. First, in order to ensure that the pump continues to operate during crystallization, a coolant flushing line needs to be added.

[0035] like Figure 2 As shown, the system includes an external flushing line 2, which is a section of stainless steel pipe added to the existing circulating water pipeline on site. The flushing line 2 is equipped with a pressure reducing valve 3, a pressure gauge 4, and an orifice plate 5 to monitor the pressure in the flushing line 2. The orifice plate 5 is installed inside a flange mounted on the flushing line 2, and has circular holes for the medium to pass through, used to control the flow rate of the medium.

[0036] like Figure 3 As shown, the magnetic pump 1 in this embodiment has a conventional magnetic pump's inlet, outlet, isolation sleeve 12, impeller, and impeller outlet mounted on the impeller, which will not be described in detail here. The difference lies in that the pump body 11 of the magnetic pump 1 has openings such as... Figure 4 The water inlet 13 shown is connected to a pipeline interface 18, and an O-ring is provided in the water inlet 13 for sealing. The flushing pipeline 2 is connected to the pipeline interface 18.

[0037] The pump body 11 in this embodiment is also provided with, as shown in the example Figure 5 The isolation sleeve 12 shown and as Figure 6 The balancing sleeve 17 is shown. A partition 14 is installed at the opening of the isolation sleeve 12. The partition 14 is annular, with a through hole in its middle for the main shaft of the magnetic pump 1 to pass through. A first return hole 15 and a second return hole 16 are respectively opened through the upper and lower sides of the surface of the partition 14, and the diameter of the first return hole 15 and the second return hole 16 is 12mm.

[0038] like Figure 3As shown, this magnetic pump 1 is a horizontal magnetic pump. The isolation sleeve 12 is horizontally arranged with its opening facing the impeller. The partition plate 14 is connected to the end of the isolation sleeve 12, and both the first return hole 15 and the second return hole 16 are connected to the interior of the isolation sleeve 12. The balance sleeve 17 is fitted on the main shaft of the magnetic pump 1 with an interference fit, and the balance sleeve 17 is located in the through hole of the partition plate 14. A flow channel is provided inside the pump body 11, which connects the water inlet hole 13 to the first return hole 15. After the flushing fluid from the flushing pipeline 2 enters the water inlet hole 13, it flows along the route shown by the arrow, lubricating and cooling the interior of the isolation sleeve 12 while flushing the crystals to the outside of the isolation sleeve 12.

[0039] Because the axial forces inside magnetic pump 1 change after the addition of flushing pipeline 2, it is necessary to calculate the change in axial force of magnetic pump 1 and perform a major overhaul. The specific calculation process is as follows:

[0040] 1. Pressure difference between the front and rear cover plates of the impeller

[0041] F1=(Π / 4)ρω(R2 2 -R1 2 ) 2 ;

[0042] Where R2 is the impeller outer diameter; R1 is the hub radius; P is the medium density; ω is the angular velocity, ω=2Πn / 60, and n is the rotational speed.

[0043] 2. Fluid momentum change

[0044] F2=ρQ(V2Z-V1Z);

[0045] Where Q is the flow rate; and V2Z and V1Z are the inlet and outlet axial velocities.

[0046] 3. Total axial force of the fluid

[0047] Fflow = F1 + F2.

[0048] 4. Axial force generated by the magnetic coupler

[0049] Because the pressure of the medium between the impeller shrouds varies with the impeller diameter:

[0050] Fmagnetism = (B 2 A×sin2Φ) / (2μ0);

[0051] B is the electromagnetic induction intensity; A is the effective area of ​​the magnetic pole; μ0 is the vacuum permeability (4Π×10^(-7)); Φ is the misalignment angle of the inner and outer magnetic rotors (usually designed to be close to 0).

[0052] 5. Others, such as pump body 1110, need to consider gravity when installed vertically, because this data is negligible when installed horizontally.

[0053] 6. Total axial force

[0054] Ftotal = Fcurrent + Fmagnetic.

[0055] Because the inlet pressure of magnetic pump 1 is 0.17 MPa and the outlet pressure is 1.74 MPa, to prevent the first return hole 15 and the second return hole 16 from being blocked by crystallization, the hole diameter is set to 12 mm. This is because the impeller diameter is Φ395 mm, the hub outer diameter is 66 mm, and the density of propylene oxide is 763 kg / m³. 3 Rotation speed 2950 r / min, flow rate 190 m³ / min 3 / h, journal 55mm, flushing fluid pressure ≥ pump inlet pressure + sealing cavity pressure (approximately equal to outlet pressure), according to the above formula, the flushing fluid pressure ≥ 1.91MPa. On-site, 2.2MPa demineralized water is used, reduced to 1.95MPa after depressurization, as the external flushing fluid. Because the pump internal pressure changes after adding external flushing, to meet the requirements of pump body 11, only a balance sleeve 17 to overcome the added axial force on pump body 11 needs to be designed. That is, Fnew = Fnew total - Foriginal:

[0056] F_new = (Π / 4)ρω(R2) 2 -R1 2 ) 2 +ρQ(V2newZ-V1Z)+(B 2 A×sin2Φ)

[0057] / (2μ0)-(Π / 4)ρω(R2 2 -R1 2 ) 2 +ρQ(V2Z-V1Z)+(B 2 A×sin2Φ) / (2μ0)=972N.

[0058] Note: Vnew = 38.7 m / s. Due to the excessively high flow velocity, if... Figure 2 As shown, the newly added orifice plate 5 reduces the flow velocity to 4 m / s, and the calculated flow rate for flushing pipeline 2 is 2.55 m³ / s. 3 / h (Cd is the thin-wall coefficient 0.62).

[0059] 7. Added cross-current value

[0060] Because the axial displacement F_axis = K × X, the original displacement is 0.15 mm, K is the axial stiffness, and X is the displacement value;

[0061] Based on the original crosslinking, the K value is 37333.33 N / mm;

[0062] Newly added crosslinking amount X new = 972 / 37333.33 - 0.15 = 0.026mm;

[0063] To overcome this cross-flow, a 3mm thick balancing sleeve 17 was added.

[0064] Working principle: The on-site operator first primes the magnetic pump 1, then opens the pressure reducing valve 3 and controls the pressure to 1.95MPa using the on-site pressure gauge 4. Once the conditions are met, the pump is officially started.

[0065] In the initial stage of startup of the propylene oxide unit, the medium contains crystalline particles. Flushing fluid is injected into pump body 11 through the flushing water pipeline. The flushing fluid flows along... Figure 3 The direction indicated by the middle arrow is used to flush the inside of the isolation sleeve 12, flushing the crystallized particles to the impeller outlet, which will prevent the inside of the inner pump body 11 from becoming blocked and causing the magnetic pump 1 to burn out.

Claims

1. A magnetic pump system with a flushing assembly, comprising a magnetic pump (1), the magnetic pump (1) having a pump body (11) and an isolation sleeve (12), characterized in that, Also includes: The water inlet (13) is located on the pump body (11); The flushing line (2) is connected to the water inlet (13); The partition (14) is fixedly connected to the end of the isolation sleeve (12); The first return hole (15) and the second return hole (16) are both opened on the partition plate (14); A balance sleeve (17) is fitted onto the pump shaft of the magnetic pump (1); The pump body (11) has a flow channel that connects the water inlet (13) with the first return hole (15) and the second return hole (16).

2. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, The water inlet (13) is equipped with an O-ring.

3. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, The water inlet (13) is equipped with a pipeline interface (18), and the flushing pipeline (2) is connected to the water inlet (13) through the pipeline interface (18).

4. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, A pressure reducing valve (3) is installed on the flushing pipeline (2).

5. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, A pressure gauge (4) is installed on the flushing pipeline (2).

6. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, An orifice plate (5) is installed on the flushing pipeline (2), and a flange is connected to the flushing pipeline (2). The orifice plate (5) is installed in the flange.

7. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, The inner diameter of the first reflux hole (15) and the second reflux hole (16) is 12 mm.

8. A magnetic pump system with a flushing assembly according to claim 1, characterized in that, The thickness of the balance sleeve (17) is 3mm.

Images