A system for regulating the temperature of a rotor of a roots vacuum pump and a method for regulating the temperature of a rotor of a roots vacuum pump

Abstract

This invention relates to the field of vacuum pump testing technology, specifically to a rotor temperature control system and method for a Roots vacuum pump, comprising a pump body, a rotor assembly, a temperature measurement system, a heating system, a cooling system, and an electronic control system. The temperature measurement system includes a wireless temperature sensor that measures the temperature of the rotor assembly and transmits the temperature signal to the electronic control system. The heating system is located at the pump body's inlet. The inner cavity of the rotor shaft of the rotor assembly is connected to the cooling system. The cooling system is electrically connected to the electronic control system. By adding a cooling system, and connecting it to the hollow rotor shaft, more heat can be removed. Simultaneously, a heating system is provided to heat the medium entering the pump body. Both the heating and cooling systems are connected to the electronic control system, which allows for precise temperature control of the rotor assembly and the internal temperature of the Roots pump cavity.

Description

Technical Field

[0001] This invention relates to the field of vacuum pump testing technology, and in particular to a rotor temperature control system and method for a Roots vacuum pump. Background Technology

[0002] A Roots pump includes a pump housing with a pump chamber, and the pump housing also has an inlet and an outlet connected to the pump chamber. A rotor assembly is disposed within the pump chamber, wherein the rotor assembly includes two figure-eight shaped rotors, which are perpendicular to each other. The gaps between the outer walls of the two rotors and between the two rotors and the inner wall of the pump housing are extremely small to ensure the normal operation of the Roots pump. A motor drives the rotor assembly to rotate. During the operation of the Roots vacuum pump, as the rotor assembly rotates, the medium to be pumped is transported from the suction side to the pressure side of the vacuum pump. The generated heat continuously accumulates and is transferred to the pump housing and rotor assembly, causing them to expand and deform under stress. This results in significant changes in the gaps between the two rotors and between the two rotors and the inner wall of the pump housing. These changes directly affect the operating efficiency of the Roots pump. Due to the uncertainty of the temperature field, Roots vacuum pumps are suitable for some very harsh application environments, requiring the internal temperature field of the Roots vacuum pump to be suitable for the specified operating conditions. For example, vacuum pumps cannot be used in frigid northern environments with outdoor temperatures of -15°C or below. Furthermore, the heat generated during the operation of a Roots vacuum pump leads to uneven temperature distribution in the dry pump, causing a difference in temperature between the Roots pump chamber and the Roots rotor. This results in inconsistent thermal deformation, and in severe cases, can cause the Roots rotor to "scrape" or "seize." In some vacuum pump applications, the pump should not be stopped arbitrarily after operation, as restarting is difficult and may lead to problems such as viscous material adhesion and rotor corrosion, affecting pumping efficiency and service life. These problems are related to the vacuum environment, flow field, and temperature field.

[0003] Currently, the internal temperature field of a dry pump is generally controlled by installing cooling pipes on the outer wall of the pump body to cool the pump chamber and by adding an external heating system; another method is to add heat dissipation fins to control the internal temperature field of the vacuum pump. However, current temperature measurement and heat dissipation methods cannot measure and control the temperature within the internal temperature field of the Roots vacuum pump. If the temperature measurement is inaccurate, the control will become meaningless, leading to a passive approach to temperature measurement and control. Therefore, the vacuum pump's effectiveness in new operating conditions still has room for improvement and potential. Summary of the Invention

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a rotor temperature control system and method for a Roots vacuum pump, which solves the technical problem that current temperature measurement and heat dissipation cannot be carried out in the internal temperature field of the Roots vacuum pump, and that inaccurate temperature measurement will render the control meaningless.

[0005] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0006] In a first aspect, embodiments of the present invention provide a rotor temperature control system for a Roots vacuum pump, comprising a pump body having a pump chamber at its center, a rotor assembly disposed within the pump chamber, wherein the rotation of the rotor assembly causes the pump body to be under negative pressure, thereby transporting the medium, and further comprising a temperature measurement system, a heating system, a cooling system, and an electrical control system.

[0007] The temperature measurement system includes a wireless temperature sensor mounted on the rotor assembly. The wireless temperature sensor can measure the temperature of the rotor assembly as a first temperature and send the signal of the first temperature to the electronic control system.

[0008] The heating system is located at the air inlet of the pump body and is electrically connected to the electronic control system. It can receive instructions from the electronic control system and start / stop the heating system to heat the medium entering from the air inlet.

[0009] The rotor shaft of the rotor assembly is a hollow tubular structure along its axial direction. The cooling system is located outside the pump body and is connected to both ends of the rotor shaft. The rotor shaft can circulate coolant and rotates relative to the cooling system. The cooling system is electrically connected to the electronic control system and can receive commands from the electronic control system to start / stop the cooling of the rotor assembly.

[0010] Optionally, the temperature measurement system further includes a plurality of measuring holes formed on the outer wall of the pump body along its radial direction toward the side close to the pump cavity;

[0011] The ratio of the axial depth of the measuring hole to the wall thickness of the pump body is 1:1.02. A temperature measuring element is installed in the measuring hole. The temperature measuring element is inserted into the measuring hole and positioned close to the pump cavity to measure the temperature of the pump cavity as a second temperature. The temperature measuring element is electrically connected to the electronic control system and sends the signal of the second temperature to the electronic control system.

[0012] Optionally, the rotor assembly includes a drive shaft, a drive rotor mounted on the drive shaft, and a driven rotor that is clearance-fitted with the drive rotor and rotates with the drive rotor, the driven rotor being mounted on the driven shaft;

[0013] Both ends of the drive shaft and the driven shaft extend outwards and are connected to the cooling system. Both the drive shaft and the driven shaft are the rotor shafts of the rotor assembly.

[0014] The cooling system includes an external cooler, a first liquid inlet cooling channel, a second liquid inlet cooling channel, a first liquid return cooling channel, and a second liquid return cooling channel disposed on the cooler.

[0015] The first liquid inlet cooling channel and the first liquid return cooling channel are dynamically sealed to both ends of the drive shaft by soft packing, so that the drive shaft can rotate relative to the first liquid inlet cooling channel and the first liquid return cooling channel.

[0016] The second liquid inlet cooling channel and the second liquid return cooling channel are dynamically sealed to both ends of the driven shaft by soft packing, so that the driven shaft can rotate relative to the second liquid inlet cooling channel and the second liquid return cooling channel.

[0017] Optionally, a first flow regulating valve and a second flow regulating valve are respectively provided on the first liquid inlet cooling channel and the second liquid inlet cooling channel. The first flow regulating valve and the second flow regulating valve are both electrically connected to the electronic control system, and the flow rate of the first flow regulating valve and the second flow regulating valve can be controlled by the electronic control system.

[0018] Optionally, the heating system includes a heating belt wrapped around the air inlet, and the heating belt is started / stopped by the electronic control system.

[0019] Optionally, there are multiple wireless temperature measuring strips, and the multiple wireless temperature measuring strips are respectively located at the tip and bottom of the inner wall of the active rotor and the driven rotor; the wireless temperature measuring strips are used to detect the temperature of the active rotor and the driven rotor, and the wireless temperature measuring strips can emit radio electromagnetic waves to the electronic control system for remote temperature measurement.

[0020] Optionally, the electronic control system includes a temperature acquisition unit and a host computer;

[0021] The temperature acquisition device is connected to the temperature measuring element via a wire, and the temperature acquisition device is used to acquire the second temperature of the temperature measuring element and connect it to the host computer via a wire to display the second temperature on the host computer.

[0022] The wireless temperature measuring chip is wirelessly connected to the host computer and displays the first temperature on the host computer.

[0023] On the other hand, a method for regulating the rotor temperature of a Roots vacuum pump, the method being based on the rotor temperature regulation system of the Roots vacuum pump, the method comprising the following steps:

[0024] S1. Start the electronic control system and the pump body, keep the cooling system and the heating system in the off state, measure the temperature of the rotor assembly through the wireless temperature measuring strip to obtain the first temperature, and send the signal of the first temperature to the electronic control system;

[0025] S2. After the pump body has been running for a period of time and the internal temperature of the pump chamber has stabilized, the temperature of the pump chamber is displayed on the electronic control system through a measuring device, and the temperature of the rotor assembly is displayed on the electronic control system through a wireless temperature measuring plate.

[0026] S3. Set a preset temperature in the electronic control system;

[0027] S4. Take the average value of the temperature of the pump chamber and the temperature of the rotor assembly at different time points in S2 as the measured temperature, and compare the measured temperature with the preset temperature.

[0028] S5. When the measured temperature is greater than the preset temperature, the electronic control system controls the cooling system to turn on, so as to deliver refrigerant into the rotor assembly for temperature regulation.

[0029] When the measured temperature is lower than the preset temperature, the electronic control system controls the heating system to turn on and the cooling system to turn off, thereby heating the medium entering the pump chamber.

[0030] Optionally, the preset temperature in S3 is a range value, which is between a first critical temperature and a second critical temperature, wherein the first critical temperature is 60°C and the second critical temperature is 80°C.

[0031] Optionally, S5 further includes setting a preset temperature difference value in the electronic control system and comparing the actual temperature difference value with the preset temperature difference value;

[0032] The measured temperature is compared with the preset temperature to obtain the actual difference, and the next step is performed based on the obtained difference.

[0033] When the measured temperature is greater than the second critical temperature: when the actual difference is greater than the preset temperature difference, the cooling system is activated, and the opening size of the first flow regulating valve and the second flow regulating valve on the first and second liquid inlet cooling channels is controlled by the electronic control system to ensure that the refrigerant flow rate delivered by the first and second liquid inlet cooling channels is 2L / min; when the actual difference is greater than half of the preset temperature difference but less than the preset temperature difference, the opening size of the first flow regulating valve and the second flow regulating valve on the first and second liquid inlet cooling channels is controlled by the cooling system to ensure that the refrigerant flow rate delivered by the first and second liquid inlet cooling channels is 1L / min; when the actual difference is greater than the first critical temperature but less than half of the preset temperature difference, the opening size of the first flow regulating valve and the second flow regulating valve on the first and second liquid inlet cooling channels is controlled by the electronic control system to ensure that the refrigerant flow rate delivered by the first and second liquid inlet cooling channels is 0.5L / min.

[0034] The beneficial effects of this invention are as follows: The rotor temperature control system and method for a Roots vacuum pump, by adding a cooling system connected to the hollow rotor shaft, allows for cooling from within the rotor assembly, thereby removing more heat and improving cooling efficiency. Simultaneously, a heating system is provided to heat the medium entering the pump body, further increasing the rotor assembly temperature. Both the heating and cooling systems are connected to an electronic control system, which can then precisely control the temperature of the rotor assembly, achieving precise control of the internal temperature of the Roots pump chamber. Researching and controlling the heating and temperature field of Roots vacuum pumps not only solves the problems of "scratching" or "jamming" of the Roots rotor but also overcomes environmental limitations imposed on Roots vacuum pumps. Furthermore, the stable temperature field results in uniform clearance and a constant fluid state. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the rotor temperature control system for a Roots vacuum pump according to the present invention.

[0036] Figure 2 for Figure 1 A partial structural diagram of the rotor assembly in the diagram;

[0037] Figure 3 for Figure 1 The schematic diagram on the right side of the middle section (only the first liquid inlet cooling channel and the first liquid return cooling channel are shown).

[0038] Explanation of reference numerals in the attached figures

[0039] 1: Pump body; 11: Pump chamber; 12: Air inlet; 13: Air outlet;

[0040] 2: Rotor assembly; 21: Drive shaft; 22: Driven rotor; 23: Driven rotor; 24: Driven shaft;

[0041] 3: Temperature measurement system; 31: Wireless temperature measuring plate; 32: Measuring hole; 33: Temperature measuring element;

[0042] 4: Heating system; 41: Heating belt;

[0043] 5: Cooling system; 51: Cooler; 52: First liquid inlet cooling channel; 53: Second liquid inlet cooling channel; 54: First liquid return cooling channel; 55: Second liquid return cooling channel; 56: First flow regulating valve; 57: Second flow regulating valve;

[0044] 6: Electrical control system; 61: Temperature acquisition device; 62: Host computer. Detailed Implementation

[0045] To better explain and facilitate understanding of the present invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Figure 1 The direction is used as the reference direction. Specifically, the air inlet 12 is "up" relative to the pump body 1; the direction of the driving rotor 22 relative to the driven rotor 23 is defined as "right"; Figure 1 The side of the drive shaft 21 and driven shaft 24 that protrudes from the pump chamber 11 is defined as "front"; the position of the rotor assembly 2 relative to the pump body 1 is defined as "inner".

[0046] Combination Figure 1-3 As shown, a rotor temperature control system for a Roots vacuum pump includes a pump body 1 with a pump chamber 11 at its center, the pump body 1 having an air inlet 12 and an air outlet 13, a rotor assembly 2 disposed in the pump chamber 11, the rotation of the rotor assembly 2 causing the pump body 1 to be under negative pressure, thereby transporting the medium, and also includes a temperature measurement system 3, a heating system 4, a cooling system 5 and an electrical control system 6.

[0047] The heating system 4 is located at the air inlet 12 of the pump body 1 and is electrically connected to the electrical control system 6. It can receive instructions from the electrical control system 6 and start / stop the heating system 4 to heat the medium entering from the air inlet 12.

[0048] The rotor shaft of rotor assembly 2 is a hollow tubular structure along its axial direction. Cooling system 5 is located outside pump body 1 and is connected to both ends of rotor shaft. Coolant can flow through rotor shaft and rotor shaft rotates relative to cooling system 5. Cooling system 5 is electrically connected to electrical control system 6 and can receive commands from electrical control system 6 to start / stop cooling rotor assembly 2.

[0049] A rotor temperature control system and method for a Roots vacuum pump are disclosed. By adding a cooling system 5 connected to the hollow rotor shaft, cooling can be achieved from within the rotor assembly 2, thus removing more heat and improving cooling efficiency. Simultaneously, a heating system 4 is provided to heat the medium entering the pump body 1, thereby increasing the temperature of the rotor assembly 2. Both the heating system 4 and the cooling system 5 are connected to an electronic control system 6, which can precisely control the temperature of the rotor assembly 2, achieving precise control of the internal temperature of the Roots pump chamber. Researching and controlling the heating and temperature field of Roots vacuum pumps not only solves the problems of "scratching" or "jamming" of the Roots rotor but also overcomes the limitations imposed by the operating environment. Furthermore, the stable temperature field results in uniform clearance and a constant fluid state.

[0050] Furthermore, the rotor assembly 2 includes a drive shaft 21, a drive rotor 22 mounted on the drive shaft 21, and a driven rotor 23 that is clearance-fitted with the drive rotor 22 and rotates with the drive rotor 22. The driven rotor 23 is mounted on a driven shaft 24. Both ends of the drive shaft 21 and the driven shaft 24 extend outwards and are connected to the cooling system 5. Both the drive shaft 21 and the driven shaft 24 are rotor shafts of the rotor assembly.

[0051] Specifically, baffles are provided on both the front and rear sides of the pump body 1. A gearbox is provided on the front end face of the baffle on the front side of the pump body 1. A motor connected to the drive shaft 21 is provided on the front side of the gearbox. The motor drives the drive shaft 21 to rotate through the gearbox, and then drives the driven shaft 24 to rotate through the gearbox. In this embodiment, the front end of the drive shaft 21 passes through the baffle, gearbox and motor in sequence and extends to the first liquid inlet cooling channel 52 connected to the external cooling system 5. The front end of the driven shaft 24 passes through the baffle and gearbox in sequence and connects to the second liquid inlet cooling channel 53 of the external cooling system 5. An end cover is provided on the rear end face of the baffle on the rear side of the pump body 1. The rear ends of both the drive shaft 21 and the driven shaft 24 pass through the end cover and connect to the return cooling channel of the cooling system 5.

[0052] In this embodiment, the cooling system 5 includes an external cooler 51, a first liquid inlet cooling channel 52, a second liquid inlet cooling channel 53, a first liquid return cooling channel 54, and a second liquid return cooling channel 55 disposed on the cooler 51.

[0053] The first inlet cooling channel 52 and the first return cooling channel 54 are dynamically sealed to both ends of the drive shaft 21 via soft packing, allowing the drive shaft 21 to rotate relative to the first inlet cooling channel 52 and the first return cooling channel 54. It should be noted that the soft packing has a simple structure, is easy to install and disassemble, has low cost, and is safe and reliable in use. Soft packing is commonly made into various shapes such as round, long, rectangular, wedge-shaped, triangular, and conical. It is a high-grade "packing" refined from a new generation of high-performance fibers with special grease and lubricant. Furthermore, soft packing is available in any size and shape, is extremely easy to install, and can be directly injected using a dedicated high-pressure gun, unlike traditional packing which requires pre-cutting. It can be used with stuffing boxes of any size.

[0054] Furthermore, the second liquid inlet cooling channel 53 and the second liquid return cooling channel 55 are dynamically sealed to both ends of the driven shaft 24 via soft packing, so that the driven shaft 24 can rotate relative to the second liquid inlet cooling channel 53 and the second liquid return cooling channel 55. The connection of the driven shaft 24 is the same as that of the drive shaft 21.

[0055] In this embodiment, a first flow regulating valve 56 and a second flow regulating valve 57 are respectively installed on the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53. Both the first flow regulating valve 56 and the second flow regulating valve 57 are electrically connected to the electronic control system 6, and the flow rates of the first flow regulating valve 56 and the second flow regulating valve 57 can be controlled by the electronic control system 6. At the same time, the host computer 62 of the electronic control system processes the temperature measurement data, thereby controlling the flow rate of the refrigerant delivered by the cooler 51, so as to achieve the effect of precisely controlling the internal temperature of the Roots pump chamber. At the same time, when the internal temperature of the chamber is lower than the preset value, the internal temperature can be regulated by the heating belt 41 to bring the internal temperature of the chamber to the preset value.

[0056] Furthermore, the heating system 4 includes a heating belt 41 wrapped around the air inlet 12, which is started / stopped by the electronic control system 6. When the temperature is low in northern winters, in order to avoid the problem of poor pump efficiency due to low temperature, the medium is heated at the air inlet 12 by the heating belt 41 to adapt to different environments.

[0057] Furthermore, the electronic control system 6 includes a temperature acquisition device 61 and a host computer 62.

[0058] Temperature acquisition device 61 is connected to temperature measuring element 33 via a wire, and is used to acquire the second temperature of temperature measuring element 33 and is connected to host computer 62 via a wire to display the second temperature on host computer 62. Wireless temperature measuring chip 31 is wirelessly connected to host computer 62 and displays the first temperature on host computer 62.

[0059] In this embodiment, the temperature measurement system 3 includes a wireless temperature measuring chip 31 disposed on the rotor assembly 2. The wireless temperature measuring chip 31 can measure the temperature of the rotor assembly 2 as a first temperature and send the signal of the first temperature to the electronic control system 6.

[0060] In this embodiment, see Figure 2 As shown, there are multiple wireless temperature measuring elements 31, located at the tip and bottom of the inner walls of the active rotor 22 and the driven rotor 23, respectively. These elements are used to detect the temperature of the active rotor 22 and the driven rotor 23, and can emit radio electromagnetic waves to the electronic control system 6 for remote temperature measurement. There are eight wireless temperature measuring elements 31 on each of the active and driven rotors. The elements are fixedly mounted on the active rotor 22 and the driven rotor 23 using fasteners. They communicate wirelessly with the host computer 62, transmitting the rotor surface temperature to the host computer 62.

[0061] Furthermore, the temperature measurement system 3 also includes multiple measuring holes 32 formed radially on the outer wall of the pump body 1 towards the side near the pump cavity 11. The ratio of the axial depth of the measuring hole 32 to the wall thickness of the pump body 1 is 1:1.02. A temperature measuring element 33 is installed in the measuring hole 32, inserted into the measuring hole 32 and positioned close to the pump cavity 11, to measure the temperature of the pump cavity 11 as a second temperature. The temperature measuring element 33 is electrically connected to the electronic control system 6 and sends the second temperature signal to the electronic control system 6. When measuring the pump cavity temperature, the temperature measuring element 33 can be placed as close to the pump cavity as possible, and the temperature measuring element 33 is positioned at the critical point where the pump wall is about to break. Therefore, while ensuring that the temperature is as close as possible to the pump cavity temperature, the pump body 1 can operate normally. By measuring both the rotor temperature and the pump cavity temperature, the rotor temperature can be measured more comprehensively and fully. Furthermore, the measurement method of the present invention allows for more comprehensive testing to accurately obtain the temperatures of the pump cavity 11 and the rotor assembly 2. The technical solution of this invention is reasonable and feasible, and can accurately test the temperature distribution of a Roots vacuum pump under actual operating conditions. It solves the technical problem of poor accuracy in current measurement methods.

[0062] It should be noted that by setting four large-area temperature measuring points at the four corners of the pump body 1, the temperature of the pump chamber 11 can be comprehensively measured, making the temperature measurement of the pump chamber 11 more accurate. Of course, this includes, but is not limited to, these four points; however, considering the overall mass of the vacuum pump, setting four measuring points here is optimal and ensures data accuracy.

[0063] Furthermore, preferably, each temperature measuring point is equipped with two measuring elements 33. The purpose of setting three is to ensure the accuracy of the measurement data while ensuring that the weight of the pump body 1 does not affect the operation of the pump body 1 itself. The temperature of the pump chamber 11 of the Roots vacuum pump is measured using a contact temperature measurement method. Eight temperature measuring holes are arranged along the axial direction on the pump chamber 11. A K-type thermocouple is placed in the temperature measuring hole to measure the temperature of the pump chamber 11, and the temperature signal is converted into a voltage signal. The temperature acquisition unit 61 receives the voltage signal and converts it into the temperature of the measured chamber. The computer displays and records it on the software of the host computer 62. It is worth noting that the axial depth of the measuring hole 32 is close to the thickness of the pump wall, and the two are in a critical state, so the obtained pump chamber temperature value is closer to the temperature of the pump chamber 11 itself.

[0064] Further, see Figure 1 The first measuring point located on the outer side has a vertical deflection angle of 45 degrees relative to the axis of the driven rotor 23 on the left, while the first measuring point located on the inner side has a vertical deflection angle of 30 degrees relative to the axis of the first rotor 23 on the left. Correspondingly, the position and angle of the temperature measuring element 33 at the first measuring point are the same as those of the first measuring point. The second measuring point and the first measuring point are arranged symmetrically with respect to the pump body 1. The third measuring point and the second measuring point are arranged symmetrically with respect to the pump body 1. Furthermore, the aforementioned angle settings ensure the overall balance of the pump body 1, preventing any deviation of the pump body 1.

[0065] Furthermore, the inner wall of the measuring hole is provided with internal threads, and the temperature measuring structure has external threads that are screwed into the internal threads. The threaded connection method is simple and convenient to install, easy to operate, and has good stability.

[0066] In this embodiment, the temperature measuring element 33 includes thermocouples and thermocouple fixing members, with a total of eight on the outer wall of the Roots pump body. The thermocouples are set axially near the Roots pump cavity through the thermocouple fixing members. The thermocouples are connected to the temperature acquisition device 61 through connecting wires. The temperature acquisition device 61 can convert the temperature signal of the Roots pump cavity into a voltage signal and transmit it to the host computer 62.

[0067] On the other hand, a method for controlling the rotor temperature of a Roots vacuum pump, the method being based on a Roots vacuum pump rotor temperature control system, includes the following steps:

[0068] S1. Start the electronic control system 6 and pump body 1, keep the cooling system 5 and heating system 4 in the off state, measure the temperature of rotor assembly 2 through wireless temperature measuring strip 31 to obtain the first temperature, and send the signal of the first temperature to the electronic control system 6.

[0069] S2. After the pump body 1 has been running for a period of time and the internal temperature of the pump chamber 11 has stabilized, the temperature of the pump chamber 11 is displayed on the electronic control system 6 through the measuring element, and the temperature of the rotor assembly 2 is displayed on the electronic control system 6 through the wireless temperature measuring plate 31.

[0070] S3. Set the preset temperature in the electronic control system 6.

[0071] S4. Take the average temperature of the pump chamber 11 and the rotor assembly 2 at different time points S2 as the measured temperature, and compare the measured temperature with the preset temperature.

[0072] S5. When the measured temperature is higher than the preset temperature, the electronic control system 6 controls the cooling system 5 to turn on, so as to deliver refrigerant into the rotor assembly 2 for temperature regulation.

[0073] When the measured temperature is lower than the preset temperature, the electronic control system 6 controls the heating system 4 to turn on and the cooling system 5 to turn off, thereby heating the medium entering the pump chamber 11.

[0074] Furthermore, the preset temperature in S3 is a range value, which is between the first critical temperature and the second critical temperature. The first critical temperature is 60℃ and the second critical temperature is 80℃.

[0075] Furthermore, S5 also includes setting a preset temperature difference value in the electronic control system 6 and comparing the actual temperature difference value with the preset temperature difference value. It should be noted that the preset temperature difference value is 20℃.

[0076] The measured temperature is compared with the preset temperature to obtain the actual difference, and the next step is performed based on the obtained difference.

[0077] When the measured temperature exceeds the second critical temperature: when the actual temperature difference is greater than the preset temperature difference, the cooling system 5 is activated, and the opening size of the first flow regulating valve 56 and the second flow regulating valve 57 on the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53 is controlled by the electronic control system 6 to ensure that the refrigerant flow rate delivered by the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53 is 2L / min; when the actual temperature difference is greater than half of the preset temperature difference but less than the preset temperature difference, the cooling system 5 controls the opening size of the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53. The opening size of the first flow regulating valve 56 and the second flow regulating valve 57 on the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53 is adjusted so that the refrigerant flow rate delivered by the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53 is 1L / min; when the actual temperature difference is greater than the preset temperature difference of less than half of the first critical temperature, the opening size of the first flow regulating valve 56 and the second flow regulating valve 57 on the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53 is controlled by the electronic control system 6 so that the refrigerant flow rate delivered by the first liquid inlet cooling channel 52 and the second liquid inlet cooling channel 53 is 0.5L / min.

[0078] In this embodiment, S1, the host computer 62 and the pump body 1 of the Roots pump are started, the cooler 51 and the heating belt 41 are kept in the closed state, and a temperature measuring element 33 is set in the measuring hole 32 to obtain the temperature of the pump chamber 11 of the Roots pump; the temperature of the active rotor 22 and the driven rotor 23 is obtained through the wireless temperature measuring strip 31.

[0079] S2. After the pump body 1 of the Roots pump has been running for a period of time and the internal temperature of the pump chamber 11 has stabilized, the temperature of the pump chamber 11 of the Roots pump is displayed on the host computer 62 through the temperature acquisition device 61, and the temperatures of the active rotor 22 and the driven rotor 23 are displayed on the host computer 62 through the wireless temperature measuring plate 31.

[0080] S3. Set a first preset temperature and a second preset temperature in the host computer 62. Further, the preset temperature in S3 is a range value, between a first critical temperature and a second critical temperature. The first critical temperature is 60℃, and the second critical temperature is 80℃. S5 also includes setting a preset temperature difference in the electronic control system 6 and comparing the actual temperature difference with the preset temperature difference. It should be noted that the preset temperature difference is 20℃.

[0081] S4. Take the average temperature of the pump chamber 11 of the Roots pump at different time points S2, and the average temperature of the driving rotor 21 and the driven rotor 23, and compare it with the first and second preset temperatures to obtain the difference.

[0082] S5. When the temperature difference is greater than a certain temperature, the host computer controls the cooling system to deliver refrigerant for temperature regulation based on the PID algorithm. The greater the temperature difference, the greater the flow rate of the delivered refrigerant. When the temperature difference is less than a certain temperature, the heating system is turned on to heat the medium delivered by the Roots pump. At the same time, the host computer reduces the flow rate of the refrigerant delivered by the cooling system based on the PID algorithm to achieve temperature regulation.

[0083] Specifically, the temperature control method includes the following steps:

[0084] S1. Turn on the power supply switch of the electrical control system, start the Roots pump, and ensure that the switches of the cooler 51 and the heating belt 41 are in the off state;

[0085] S2. A temperature measuring element 33 is installed in the measuring hole 32 to obtain the temperature of the pump chamber 11 of the Roots pump; a wireless temperature measuring strip 31 is used to obtain the temperature of the driving rotor 21 and the driven rotor 23.

[0086] S3. After the Roots pump body 1 has been running for a period of time and the internal temperature of the pump chamber 11 has stabilized, the temperature of the pump chamber 11 is displayed on the host computer 62 via the temperature acquisition device 61, and the temperatures of the driving rotor 21 and the driven rotor 23 are displayed on the host computer 62 via the wireless temperature measuring strip 31. The average value of the temperature of the pump chamber 11 and the temperatures of the driving rotor 21 and the driven rotor 23 at different time points is taken as the measured temperature.

[0087] S4. Set a first preset temperature of 60°C and a second preset temperature of 80°C in the host computer 62. At this temperature, the operating performance of the Roots pump body 1 is optimal.

[0088] S5. In the host computer 62, compare the measured temperature with the preset temperature to obtain the difference, and proceed to the next step based on the obtained difference:

[0089] S51. When the measured temperature is greater than the preset temperature: when the difference is greater than 20℃, start the cooler and set the refrigerant flow rate to 2L / min through the upper computer's regulating valve; when the difference is greater than 10℃ but less than 20℃, operate the regulating valve through the upper computer to deliver the refrigerant flow rate to 1L / min; when the difference is greater than 1℃ but less than 10℃, operate the regulating valve through the upper computer to deliver the refrigerant flow rate to 0.5L / min, in order to cool the internal temperature of the pump chamber 11 of the Roots pump.

[0090] S52. When the measured temperature is lower than the preset temperature, turn on the heating belt 41 switch and turn off the cooler 51 to heat the medium entering the pump chamber 11 of the Roots pump, thereby indirectly heating the inside of the pump chamber 11 of the Roots pump.

[0091] S6. Repeat steps S51 and S52 to maintain the difference between the measured temperature and the preset temperature within 1℃.

[0092] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0093] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0094] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0095] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0096] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for controlling the rotor temperature of a Roots vacuum pump, characterized in that: The control method is based on the rotor temperature control system of the Roots vacuum pump; The rotor temperature control system of the Roots vacuum pump includes a pump body (1) with a pump chamber (11) in the center and a rotor assembly (2) disposed in the pump chamber (11). The rotation of the rotor assembly (2) makes the pump body (1) negative pressure, thereby transporting the medium. The system is characterized by further including a temperature measurement system (3), a heating system (4), a cooling system (5) and an electrical control system (6). The temperature measurement system (3) includes a wireless temperature measuring chip (31) disposed on the rotor assembly (2). The wireless temperature measuring chip (31) can measure the temperature of the rotor assembly (2) as a first temperature and send the signal of the first temperature to the electronic control system (6). The heating system (4) is located at the air inlet (12) of the pump body (1), and the heating system (4) is electrically connected to the electrical control system (6). It can receive the instructions of the electrical control system (6) and start / stop the heating system (4) to heat the medium entering from the air inlet (12). The rotor shaft of the rotor assembly (2) is a hollow tubular structure along its axial direction. The cooling system (5) is located outside the pump body (1) and is connected to both ends of the rotor shaft. The rotor shaft can circulate coolant and rotates relative to the cooling system (5). The cooling system (5) is electrically connected to the electrical control system (6) and can receive instructions from the electrical control system (6) to start / stop the cooling of the rotor assembly (2). The control method includes the following steps: S1. Start the electronic control system (6) and the pump body (1), keep the cooling system (5) and the heating system (4) in the off state, measure the temperature of the rotor assembly (2) through the wireless temperature measuring chip (31) to obtain the first temperature, and send the signal of the first temperature to the electronic control system (6); S2. After the pump body (1) has been running for a period of time and the internal temperature of the pump chamber (11) has stabilized, the temperature of the pump chamber (11) is displayed on the electronic control system (6) through a measuring device, and the temperature of the rotor assembly (2) is displayed on the electronic control system (6) through a wireless temperature measuring chip (31). S3. Set a preset temperature in the electronic control system (6); S4. Take the average temperature of the pump chamber (11) and the rotor assembly (2) at different time points in S2 as the measured temperature, and compare the measured temperature with the preset temperature. S5. When the measured temperature is greater than the preset temperature, the electronic control system (6) controls the cooling system (5) to turn on, so as to deliver refrigerant into the rotor assembly (2) for temperature regulation. When the measured temperature is lower than the preset temperature, the electronic control system (6) controls the heating system (4) to turn on and the cooling system (5) to turn off, thereby heating the medium entering the pump chamber (11); The preset temperature in S3 is a range value, which is between a first critical temperature and a second critical temperature. The first critical temperature is 60°C and the second critical temperature is 80°C. S5 also includes setting a preset temperature difference value in the electronic control system (6) and comparing the actual temperature difference value with the preset temperature difference value; The measured temperature is compared with the preset temperature to obtain the actual difference, and the next step is performed based on the obtained difference. When the measured temperature is greater than the second critical temperature: when the actual difference is greater than the preset temperature difference, the cooling system (5) is started, and the opening size of the first flow regulating valve (56) and the second flow regulating valve (57) on the first liquid inlet cooling channel (52) and the second liquid inlet cooling channel (53) is controlled by the electronic control system (6) so that the refrigerant flow rate delivered by the first liquid inlet cooling channel (52) and the second liquid inlet cooling channel (53) is 2L / min; when the actual difference is greater than half of the preset temperature difference but less than the preset temperature difference, the opening size of the first flow regulating valve (56) and the second flow regulating valve (57) on the first liquid inlet cooling channel (52) and the second liquid inlet cooling channel (53) is controlled by the cooling system (5) so that the refrigerant flow rate delivered by the first liquid inlet cooling channel (52) and the second liquid inlet cooling channel (53) is 1L / min.

2. The method for controlling the rotor temperature of a Roots vacuum pump as described in claim 1, characterized in that: The temperature measurement system (3) also includes a plurality of measuring holes (32) provided on the outer wall of the pump body (1) along its radial direction toward the side close to the pump cavity (11). The ratio of the axial depth of the measuring hole (32) to the wall thickness of the pump body (1) is 1:1.

02. A temperature measuring element (33) is provided in the measuring hole (32). The temperature measuring element (33) is inserted into the measuring hole (32) and is located close to the pump cavity (11) to measure the temperature of the pump cavity (11) as a second temperature. The temperature measuring element (33) is electrically connected to the electronic control system (6) and sends the signal of the second temperature to the electronic control system (6).

3. The method for controlling the rotor temperature of a Roots vacuum pump as described in claim 1, characterized in that: The rotor assembly (2) includes a drive shaft (21), a drive rotor (22) mounted on the drive shaft (21), and a driven rotor (23) that is clearance-fitted with the drive rotor (22) and rotates with the drive rotor (22). The driven rotor (23) is mounted on the driven shaft (24). Both ends of the drive shaft (21) and the driven shaft (24) extend outwards and are connected to the cooling system (5). The drive shaft (21) and the driven shaft (24) are both rotor shafts of the rotor assembly (2). The cooling system (5) includes an external cooler (51), a first liquid inlet cooling channel (52), a second liquid inlet cooling channel (53), a first liquid return cooling channel (54), and a second liquid return cooling channel (55) disposed on the cooler (51). The first liquid inlet cooling channel (52) and the first liquid return cooling channel (54) are dynamically sealed to both ends of the drive shaft (21) by soft packing, so that the drive shaft (21) can rotate relative to the first liquid inlet cooling channel (52) and the first liquid return cooling channel (54); The second liquid inlet cooling channel (53) and the second liquid return cooling channel (55) are dynamically sealed to both ends of the driven shaft (24) by soft packing, so that the driven shaft (24) can rotate relative to the second liquid inlet cooling channel (53) and the second liquid return cooling channel (55).

4. The method for controlling the rotor temperature of a Roots vacuum pump as described in claim 3, characterized in that: A first flow regulating valve (56) and a second flow regulating valve (57) are respectively provided on the first liquid inlet cooling channel (52) and the second liquid inlet cooling channel (53). The first flow regulating valve (56) and the second flow regulating valve (57) are both electrically connected to the electronic control system (6) and can control the flow rate of the first flow regulating valve (56) and the second flow regulating valve (57) through the electronic control system (6).

5. The method for controlling the rotor temperature of a Roots vacuum pump as described in claim 1, characterized in that: The heating system (4) includes a heating belt (41) wrapped around the air inlet (12), and the heating belt (41) is started / stopped by the electronic control system (6).

6. The method for controlling the rotor temperature of a Roots vacuum pump as described in claim 3, characterized in that: There are multiple wireless temperature measuring strips (31), and the multiple wireless temperature measuring strips (31) are respectively located at the tip and bottom of the inner wall of the active rotor (22) and the driven rotor (23); the wireless temperature measuring strips (31) are used to detect the temperature of the active rotor (22) and the driven rotor (23), and the wireless temperature measuring strips (31) can emit radio electromagnetic waves to the electronic control system (6) for remote temperature measurement.

7. The method for controlling the rotor temperature of a Roots vacuum pump as described in claim 2, characterized in that: The electronic control system (6) includes a temperature acquisition device (61) and a host computer (62). The temperature acquisition device (61) is connected to the temperature measuring element (33) via a wire, and the temperature acquisition device (61) is used to acquire the second temperature of the temperature measuring element (33) and connect it to the host computer (62) via a wire to display the second temperature on the host computer (62); The wireless temperature measuring chip (31) is wirelessly connected to the host computer (62) and displays the first temperature on the host computer (62).

Images