Roots vacuum unit for solvent recovery

Abstract

The invention relates to the technical field of vacuum equipment, in particular to a Roots vacuum unit for solvent recovery. Comprising a pump shell, the pump shell communicates with an exhaust pipe, the pump shell is rotationally connected with rotating blocks distributed in a rectangular array mode, the rotating blocks are fixedly connected with rotating shafts, every two adjacent rotating shafts on different sides are jointly and rotationally connected with a rotor, and first cooling cavities distributed in a mirror image mode are formed in the pump shell; and flow limiting plates which are uniformly distributed in a mirror image manner are arranged in the first cooling cavity close to one side of the exhaust pipe, and first blocking plates which are distributed in an array manner and second blocking plates which are distributed in an array manner are fixedly connected to the flow limiting plates. Through guiding of the first blocking plate and the second blocking plate on the flow limiting plate, the local flow speed of cooling liquid is increased while the cooling area is increased, so that targeted heat dissipation is conducted on the position with high heat production, the overall cooling uniformity of the pump shell is improved, the probability that parts have problems due to thermal stress is reduced, and the stability of vacuum performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum equipment, in particular to a Roots vacuum unit for solvent recovery. BACKGROUND

[0002] The Roots vacuum unit is a kind of high-efficiency and energy-saving vacuum equipment, which has important application in the solvent recovery system. It can promote the evaporation, condensation and separation of the solvent by reducing the boiling point of the solvent under vacuum conditions, so as to realize the efficient recovery of the solvent. The unit relies on mechanical compression of gas, and uses the rotating rotor inside the Roots pump (dry vacuum pump) to suck and compress the gas from the inlet to the outlet, so as to establish and maintain vacuum in the system.

[0003] At present, the heat dissipation of the pump body of the Roots pump in such a unit mainly depends on the externally arranged heat dissipation fins during the working process. Since the heat of the Roots pump mainly comes from the gas compression process, the compression area is often concentrated on the rear half side of the pump body, resulting in that the heat generated at this part is much higher than that at the front half side. However, the existing heat dissipation structure covers a wide range and cannot accurately and directionally dissipate heat from the main heat source, resulting in uneven cooling of the pump body.

[0004] Such uneven heat dissipation is easy to cause local temperature rise of the pump body, which not only affects the running efficiency and long-term stability of the Roots pump, but also causes the deformation or wear of the key components due to thermal stress, thereby shortening the service life of the equipment. In addition, the large temperature difference also affects the gap precision between the rotor and the pump shell, and reduces the stability of the vacuum performance. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings, the present application provides a Roots vacuum unit for solvent recovery.

[0006] Technical scheme: A Roots vacuum unit for solvent recovery, comprising a pump shell, the pump shell is communicated with an air inlet pipe and an air outlet pipe, the pump shell is rotatably connected with a rectangular array of rotating blocks, the rotating blocks are fixedly connected with rotating shafts, and the rotating shafts on different sides are rotatably connected with rotors, the pump shell is provided with mirror image distributed first cooling cavities, the first cooling cavities near the air outlet pipe are provided with uniformly and mirror image distributed flow limiting plates, the flow limiting plates are fixedly connected with an array of first blocking plates and an array of second blocking plates, and the array of first blocking plates and the array of second blocking plates are staggered.

[0007] As a preferred, the middle part of the first blocking plate is provided with a first mixing hole, the second blocking plate is provided with a mirror image distributed second mixing hole, and the mirror image distributed second mixing holes are respectively located on both sides of the corresponding second blocking plate.

[0008] As preferred, the rotor is internally provided with a second cooling cavity, the rotating shaft is fixedly connected with mirror image distributed flow pipes, the flow pipes are communicated with the second cooling cavity, one side of the rotating shaft is rotationally connected with an adjusting shell, and mirror image distributed adjusting shells are commonly communicated with an injection pipe.

[0009] As preferred, the exhaust pipe is communicated with a pressure measuring shell, the pressure measuring shell is slidably connected with a sliding piston, a spring is arranged between the pressure measuring shell and the sliding piston, and the pressure measuring shell is communicated with the intake pipe through a pressure passing pipe.

[0010] As preferred, the adjusting shell is rotationally connected with a flow resistance plate, the flow resistance plate is fixedly connected with an adjusting rod, the adjusting rod is rotationally connected with the adjusting shell, a first sliding plate is slidably and rotationally connected on the adjusting rod, and mirror image distributed first sliding plates are commonly rotationally connected with a second sliding plate.

[0011] As preferred, the second sliding plate is rotationally connected with a rotating shell, the rotating shell is screwedly connected with a fixing rod, the fixing rod is fixedly connected with the sliding piston, and the fixing rod is slidably connected with the pressure measuring shell.

[0012] As preferred, a protrusion is fixedly connected on the first sliding plate, a recess is arranged on the adjusting rod, the protrusion slides in the corresponding recess, and the recess is an inclined sliding groove.

[0013] As preferred, the rotor is fixedly connected with a fixing block, the fixing block is fixedly connected with mirror image distributed expansion shells, the fixing block and the expansion shells are located in the second cooling cavity, and the fixing block divides the second cooling cavity.

[0014] As preferred, mirror image distributed pressure measuring cavities are arranged on the rotating block, a pressure measuring piston is slidably connected in the pressure measuring cavities, center-symmetrically distributed shunt pipes are fixedly connected on the rotating block, the shunt pipes are used for communicating the pressure measuring cavities with corresponding expansion shells, and the shunt pipes are fixedly connected with corresponding fixing blocks.

[0015] As preferred, first reinforcing ribs in linear array distribution and second reinforcing ribs in linear array distribution are fixedly connected between the expansion shells and the fixing blocks, the first reinforcing ribs in linear array distribution and the second reinforcing ribs in linear array distribution are staggered, uniform distribution of through holes are arranged on the first reinforcing ribs and the second reinforcing ribs, and the through holes on the first reinforcing ribs and the second reinforcing ribs are staggered.

[0016] Compared with the prior art, the present application has the advantages that: the present application increases the cooling area and improves the local flow rate of the cooling liquid (i.e. improves the mixing degree of the cooling liquid) through the guidance of the first blocking plate and the second blocking plate on the flow limiting plate, thereby performing targeted heat dissipation on the position with high heat generation, improving the uniformity of the overall cooling of the pump shell, reducing the probability of problems caused by thermal stress of the parts, and improving the stability of the vacuum performance; the pressure difference on both sides of the pump body is dynamically monitored by the pressure measuring shell, and when the pressure difference fluctuates, the flow rate of the cooling liquid in the second cooling cavity is adjusted synchronously to match the working heat generation, thereby improving the heat dissipation effect and saving the amount of cooling liquid; the gap between the expansion shell and the rotor is reduced through the expansion of the expansion shell under pressure, thereby improving the flow rate of the cooling liquid under the condition that the cooling area remains unchanged, i.e. the greater the pressure on one side of the rotor (the higher the heat generation on one side), the higher the heat dissipation on that side is synchronized to prevent excessive thermal expansion of the rotor, ensure the stability of the gap between the two rotors, and improve the practicality of the device. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of the three-dimensional structure of the present application; Figure 2 is a schematic diagram of the three-dimensional structure of the internal structure of the pump shell of the present application; Figure 3 is a schematic diagram of the three-dimensional structure of the first cooling cavity and the flow limiting plate of the present application; Figure 4 is a schematic diagram of the three-dimensional structure of the first blocking plate and the second blocking plate of the present application; Figure 5 is a schematic diagram of the three-dimensional structure of the rotating block and the rotating shaft of the present application; Figure 6 is a schematic diagram of the three-dimensional structure of the fixed block and the expansion shell of the present application; Figure 7 is a schematic diagram of the three-dimensional structure of the internal structure of the rotor of the present application; Figure 8 is a schematic diagram of the three-dimensional structure of the second cooling cavity of the present application; Figure 9 is a schematic diagram of the three-dimensional structure of the pressure measuring shell and the sliding piston of the present application; Figure 10 is a schematic diagram of the three-dimensional structure of the flow blocking plate and the adjusting rod of the present application; Figure 11 is a schematic diagram of the three-dimensional structure of the protrusion and the groove of the present application.

[0018] The figure label name: 1, pump shell, 2, intake pipe, 3, exhaust pipe, 4, rotating block, 5, rotating shaft, 6, rotor, 7, first cooling cavity, 8, flow limiting plate, 9, first blocking plate, 10, second blocking plate, 11, first mixing hole, 12, second mixing hole, 13, second cooling cavity, 14, flow pipe, 15, adjusting shell, 16, injection pipe, 17, pressure measuring shell, 18, sliding piston, 19, pressure pipe, 20, flow resistance plate, 21, adjusting rod, 22, first sliding plate, 23, second sliding plate, 24, rotating shell, 25, fixed rod, 26, protruding block, 27, groove, 28, fixed block, 29, expansion shell, 30, pressure measuring cavity, 31, pressure measuring piston, 32, flow dividing pipe, 33, first reinforcing rib, 34, second reinforcing rib. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0020] Embodiment 1 A Roots vacuum unit for solvent recovery is used for targeted heat dissipation when the Roots pump is working, so as to reduce the probability of uneven cooling of the pump body.

[0021] As Figures 1-4As shown, the Roots pump comprises a pump shell 1, the pump shell 1 is communicated with an air inlet pipe 2 and an air outlet pipe 3, the air inlet pipe 2 is located above the air outlet pipe 3, the pump shell 1 is rotatably connected with four rotating blocks 4 arranged in a rectangular array, the rotating blocks 4 are dynamically sealed with the pump shell 1, every two adjacent rotating blocks 4 are mirror image distributed, the rotating blocks 4 are fixedly connected with rotating shafts 5 at the middle part, the left two rotating shafts 5 are meshed and driven with each other through gears, the front two rotating shafts 5 and the rear two rotating shafts 5 are rotatably connected with rotors 6 respectively, the two rotors 6 are cooperatively matched to compress air, the pump shell 1 is provided with two first cooling cavities 7 mirror image distributed above and below, the left and right sides of the pump shell 1 are respectively provided with pipelines for communicating the two first cooling cavities 7, wherein the left side is a liquid inlet pipe and the right side is a liquid outlet pipe, the first cooling cavity 7 below is provided with flow limiting plates 8 uniformly and mirror image distributed front and back, the flow limiting plates 8 are fixedly connected with first blocking plates 9 arranged in an array and second blocking plates 10 arranged in an array, the flow limiting plates 8, the first blocking plates 9 and the second blocking plates 10 are in contact with the inner wall of the first cooling cavity 7, the first blocking plates 9 and the second blocking plates 10 on the same flow limiting plate 8 are located at different sides of the flow limiting plate 8 and are staggered in the left and right directions, the middle part of the first blocking plate 9 is provided with a first mixing hole 11, the first mixing hole 11 is located at the middle part of the first blocking plate 9, the second blocking plate 10 is provided with two second mixing holes 12 mirror image distributed, the two second mixing holes 12 are respectively located at the upper and lower sides of the second blocking plate 10, that is, the cooling liquid passes through the first mixing hole 11 on the first blocking plate 9 and is blocked at the middle part of the second blocking plate 10 to limit the flow path and increase the mixing degree of the cooling liquid, so as to improve the cooling effect.

[0022] As Figures 5-11As shown, the rotor 6 is provided with a second cooling cavity 13, the rotating shaft 5 is fixedly connected with mirror image distributed flow pipes 14, two flow pipes 14 are communicated with the left and right sides of the second cooling cavity 13, for injecting cooling medium into the second cooling cavity 13, the flow pipe 14 on the right side is connected with an external cooling supply system through a flange, for backflow, the left rotating shaft 5 is rotatably connected with an adjusting shell 15 on the left side, the upper sides of the two adjusting shells 15 are commonly communicated with an injection pipe 16, the exhaust pipe 3 is communicated with a pressure measuring shell 17, the pressure measuring shell 17 is slidably connected with a sliding piston 18, and they are dynamically sealed, a spring is arranged between the pressure measuring shell 17 and the sliding piston 18, the spring is in a natural extension state at the beginning, when the Roots pump is started, the sliding piston 18 extrudes the spring under pressure difference, so that the sliding piston 18 is stable after the pressure difference is stable, the pressure measuring shell 17 and the inlet pipe 2 are communicated with a pressure communication pipe 19, the communication position of the pressure communication pipe 19 and the pressure measuring shell 17 is located on the left side of the sliding piston 18, the adjusting shell 15 is rotatably connected with a flow resistance plate 20, the flow resistance plate 20 is provided with a semicircular through hole, and the adjusting shell 15 is provided with a semicircular baffle, the two are cooperatively matched to control the flow area of the injection flow pipe 14 of the adjusting shell 15, the two flow resistance plates 20 are fixedly connected with adjusting rods 21, the adjusting rods 21 are rotatably connected with the adjusting shell 15, and they are dynamically sealed, the first sliding plates 22 are slidably and rotatably connected on the adjusting rods 21, the second sliding plate 23 is rotatably connected with the two first sliding plates 22, the lower part of the second sliding plate 23 is rotatably connected with a rotating shell 24, the rotating shell 24 is threadedly connected with a fixed rod 25 fixedly connected with the sliding piston 18, the fixed rod 25 is slidably connected with the pressure measuring shell 17, and they are dynamically sealed, the inner ring of the first sliding plate 22 is fixedly connected with a protrusion 26, the adjusting rod 21 is provided with a groove 27, the protrusion 26 slides in the corresponding groove 27, and the groove 27 is an inclined sliding groove.

[0023] The working process of the Roots pump in the embodiment is as follows: Preparation process: when the device is used for solvent recovery, the user first connects the inlet pipe 2 with the condenser, connects the exhaust pipe 3 with the front stage pump, then connects the external cooling system with the flow pipe 14, for circulating cooling medium (the cooling medium is taken as cooling liquid hereinafter) in the second cooling cavity 13, synchronously connects the left and right side pipes of the pump shell 1 with the external cooling system, for circulating cooling medium in the two first cooling cavities 7, connects the left rear rotating shaft 5 with the external power, and the preparation work is completed.

[0024] Working process: after the preparation work is completed, the user starts the pre-stage pump, and when the pressure in the system is reduced to the starting pressure of the Roots pump, the user drives the left rear rotating shaft 5 to rotate through external power, the left rear rotating shaft 5 drives the left front rotating shaft 5 to rotate in the opposite direction through the gear set, and the two rotating shafts 5 on the left side drive the two rotors 6 to rotate in the opposite direction continuously, so that the evaporated solvent is gradually extracted. With the continuous rotation of the two rotors 6, the rotors 6 continuously compress the gas, thereby improving the vacuum degree for solvent evaporation. In the process of gas compression, the lower part of the pump shell 1 and the rotor 6 are continuously heated. In order to prevent the gap from changing due to thermal expansion of the lower part of the pump shell 1 and the rotor 6, which affects the normal work of the Roots pump, the user starts the external cooling system. The external cooling system continuously circulates cooling liquid into the two first cooling cavities 7 and the two rotors 6 through the two pipelines of the pump shell 1, thereby preventing the pump shell 1 and the two rotors 6 from overheating.

[0025] When the cooling liquid enters the lower first cooling cavity 7, it is guided and limited by the flow limiting plate 8 inside, and the cooling liquid is divided. Taking the front and rear two adjacent flow limiting plates 8 as an example, the cooling liquid flows from left to right between the front and rear two flow limiting plates 8. When the cooling liquid flows through the first blocking plate 9 on the front flow limiting plate 8, part of the cooling liquid moves to the right through the first mixing hole 11, and the other part of the cooling liquid moves backward under the guidance of the first blocking plate 9. At this time, the flow area of the cooling liquid is reduced, thereby making the cooling liquid accelerate temporarily at this point to improve the cooling effect. In this process, the cooling liquid accelerates to the right next to the rear flow limiting plate 8, and the flow limiting plate 8 also increases the cooling area of the lower first cooling cavity 7. As the cooling liquid continues to move to the right, the cooling liquid contacts the second blocking plate 10 on the rear flow limiting plate 8. The same as the first blocking plate 9, part of the cooling liquid continues to flow to the right along the gap between the second blocking plate 10 and the front flow limiting plate 8, and the other part of the cooling liquid continues to move to the right through the two second mixing holes 12, thereby disturbing the flow state of the cooling liquid and reducing the probability of laminar flow of the cooling liquid in the flow process. Repeat the above steps to cool the pump shell 1 until the Roots pump is used up. Through the guidance of the first blocking plate 9 and the second blocking plate 10 on the flow limiting plate 8, the cooling area is increased while the local flow rate of the cooling liquid is increased (i.e. the mixing degree of the cooling liquid is increased), thereby targeted heat dissipation for the position with high heat generation, improving the uniformity of the overall cooling of the pump shell 1, reducing the probability of problems caused by thermal stress of the parts, and improving the stability of the vacuum performance.

[0026] In the above preparation, the user adjusts the flow area of the adjusting shell 15 and the flow pipe 14 according to the pressure difference on both sides of the Roots pump: the user rotates the rotating shell 24, the rotating shell 24 drives the second sliding plate 23 to move left through the threaded fixed rod 25, the second sliding plate 23 drives the two first sliding plates 22 to move left synchronously, in the process of moving left, the first sliding plate 22 slides in the adjacent groove 27 through the protrusion 26 on the first sliding plate 22, thereby extruding and driving the adjusting rod 21 to rotate, the adjusting rod 21 drives the flow resistance plate to rotate, thereby making the adjusting shell 15 gradually lose the shielding of the through hole on the flow resistance plate 20, until the area of the through hole on the flow resistance plate 20 that loses the shielding reaches the preset adjustment value, the user stops rotating the rotating shell 24, at this time, the adjustment of the flow area of the adjusting shell 15 and the flow pipe 14 is completed.

[0027] After the adjustment of the flow area of the adjusting shell 15 and the flow pipe 14 is completed, the above steps are repeated to perform the solvent recovery operation, in this process, because the pressure in the exhaust pipe 3 is greater than the pressure in the inlet pipe 2, the sliding piston 18 moves left under the action of the pressure, while extruding the spring between the sliding piston 18 and the pressure measuring shell 17, until the force provided by the spring between the sliding piston 18 and the pressure measuring shell 17 balances with the pressure difference, the sliding piston 18 stops moving, in this process, the sliding piston 18 drives the fixed rod 25 to move left synchronously, the fixed rod 25 drives the first sliding plate 22 to move left through the rotating shell 24, the first sliding plate 22 drives the adjusting rod 21 to rotate through the protrusion 26 extruding the corresponding groove 27, the adjusting rod 21 drives the flow resistance plate 20 to rotate, thereby adjusting the cooling liquid flow according to the pressure difference (under the same conditions, the greater the pressure difference, the higher the heat production), in the working process, the external cooling system injects cooling liquid into the adjusting shell 15 through the injection pipe 16, the cooling liquid enters the two flow pipes 14 through the through hole on the flow resistance plate 20 respectively, the cooling liquid enters the second cooling cavity 13 after passing through the flow pipe 14, thereby cooling the working rotor 6, the pressure difference on both sides of the pump body is dynamically monitored through the pressure measuring shell 17, when the pressure difference fluctuates, the cooling liquid flow in the second cooling cavity 13 is adjusted synchronously to match the working heat production, thereby improving the cooling effect and saving the amount of cooling liquid.

[0028] Example 2 The embodiment discloses a Roots vacuum unit for solvent recovery, which is further improved on the basis of example 1.

[0029] The structure, connection relationship and working process of the mounting structure in example 1 are not described again, and the working principle of the following structure is mainly described.

[0030] As Figures 5-8As shown, the rotor 6 is fixed with a fixed block 28, the fixed block 28 divides the second cooling cavity 13 into two chambers which are not communicated with each other, the fixed block 28 is fixed with two expansion shells 29 which are mirror distributed, the fixed block 28 and the expansion shell 29 are located in the second cooling cavity 13, the expansion shell 29 is made of elastic material, the flow path of the cooling liquid is the chamber composed of the rotor 6, the expansion shell 29 and the fixed block 28, and the chamber is mirror distributed in the rotor 6, the rotating block 4 is provided with two pressure measuring cavities 30 which are mirror distributed, the two pressure measuring cavities 30 on the same rotating block 4 are located on the two sides of the rotor 6 respectively, and the pressure measuring cavity 30 is connected with the corresponding expansion shell 29 through the shunt pipe 32. Figure 6 For example, at this time, the pressure measuring piston 31 is in the normal position (i.e. the Roots pump is in the non-working state), when the Roots pump works, the pressure measuring piston 31 moves towards the middle of the pump body 1 when being located at the low pressure side, and moves away from the middle of the pump body 1 when being located at the high pressure side, the pressure measuring cavity 30 is slidably connected with the pressure measuring piston 31, and the two are dynamically sealed, the rotating block 4 is fixed with the shunt pipe 32 which is centrally symmetrically distributed, the shunt pipe 32 is fixed with the corresponding fixed block 28, the shunt pipe 32 is provided with the exhaust holes which are linearly arrayed, so as to ensure that the expansion shell 29 is uniformly expanded, the shunt pipe 32 is used for connecting the pressure measuring cavity 30 with the corresponding expansion shell 29, the expansion shell 29 and the fixed block 28 are fixed with the first reinforcing ribs 33 and the second reinforcing ribs 34 which are linearly arrayed, the first reinforcing ribs 33 and the second reinforcing ribs 34 are made of elastic material, the first reinforcing ribs 33 and the second reinforcing ribs 34 which are linearly arrayed are staggered, so as to ensure that the expansion shell 29 is uniformly expanded, the first reinforcing ribs 33 and the second reinforcing ribs 34 are provided with the through holes which are uniformly distributed, and the through holes on the first reinforcing ribs 33 and the second reinforcing ribs 34 are staggered, so as to improve the tensile strength of the expansion shell 29.

[0031] The working process of the Roots pump in the embodiment is as follows: In the working process of the above embodiment, the two surfaces of the rotor 6 alternately compress the gas, so that the two surfaces of the rotor 6 are unevenly heated at any moment, and the side of the rotor 6 with greater pressure is heated more, and in the working process of the embodiment, the rotating block 4 rotates with the rotor 6, when the pressure of one side of the rotor 6 increases, the corresponding pressure measuring piston 31 is pressed and moves into the pressure measuring cavity 30, the gas in the pressure measuring cavity 30 enters the expansion shell 29 through the shunt pipe 32, the expansion shell 29 is expanded under pressure and reduces the gap between the expansion shell 29 and the rotor 6, so as to increase the flow rate of the cooling liquid, that is, the greater the pressure of the side of the rotor 6 (the higher the heat generation of the side), the higher the heat dissipation of the side, so as to prevent the rotor 6 from being excessively expanded, and to ensure that the gap between the two rotors 6 is stable, thereby improving the practicability of the device.

[0032] The above only describes the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A Roots vacuum unit for solvent recovery, characterized in that, The pump housing (1) is connected to an intake pipe (2) and an exhaust pipe (3). A rectangular array of rotating blocks (4) are rotatably connected to the pump housing (1). A rotating shaft (5) is fixed to the rotating block (4). Two adjacent rotating shafts (5) on different sides are rotatably connected to a rotor (6). A mirror-distributed first cooling chamber (7) is provided inside the pump housing (1). A uniform and mirror-distributed flow-limiting plate (8) is provided in the first cooling chamber (7) near the exhaust pipe (3). An array of first blocking plates (9) and an array of second blocking plates (10) are fixed to the flow-limiting plate (8). The array of first blocking plates (9) and array of second blocking plates (10) are staggered.

2. A Roots vacuum unit for solvent recovery according to claim 1, characterized in that The first barrier plate (9) is provided with a first mixing hole (11) in the middle, and the second barrier plate (10) is provided with a mirror-distributed second mixing hole (12), which are located on both sides of the corresponding second barrier plate (10).

3. A Roots vacuum unit for solvent recovery according to claim 1, characterized in that, The rotor (6) is provided with a second cooling chamber (13), and the rotating shaft (5) is fixedly connected with a mirror-distributed flow pipe (14). The flow pipe (14) is connected to the second cooling chamber (13). The rotating shaft (5) on one side is rotatably connected to an adjustment shell (15). The mirror-distributed adjustment shells (15) are connected to an injection pipe (16).

4. A Roots vacuum unit for solvent recovery according to claim 3, characterized in that The exhaust pipe (3) is connected to a pressure measuring shell (17), and a sliding piston (18) is slidably connected inside the pressure measuring shell (17). A spring is provided between the pressure measuring shell (17) and the sliding piston (18), and a pressure-passing pipe (19) is connected between the pressure measuring shell (17) and the intake pipe (2).

5. A Roots vacuum unit for solvent recovery according to claim 4, characterized in that A baffle plate (20) is rotatably connected inside the regulating shell (15). An adjusting rod (21) is fixedly connected to the baffle plate (20). The adjusting rod (21) is rotatably connected to the regulating shell (15). A first sliding plate (22) is rotatably connected to the adjusting rod (21). The first sliding plates (22) which are mirror-distributed are rotatably connected to a second sliding plate (23).

6. A Roots vacuum unit for solvent recovery according to claim 5, characterized in that The second sliding plate (23) is rotatably connected to a rotating shell (24), and the rotating shell (24) is threadedly connected to a fixing rod (25). The fixing rod (25) is fixedly connected to the sliding piston (18), and the fixing rod (25) is slidably connected to the pressure measuring shell (17).

7. A Roots vacuum unit for solvent recovery according to claim 6, characterized in that A protrusion (26) is fixedly connected to the first sliding plate (22), and a groove (27) is provided on the adjusting rod (21). The protrusion (26) slides in the corresponding groove (27), and the groove (27) is an inclined sliding groove.

8. A Roots vacuum unit for solvent recovery according to claim 3, characterized in that, The rotor (6) is fixedly connected to a fixing block (28), and the fixing block (28) is fixedly connected to a mirror-distributed expansion shell (29). The fixing block (28) and the expansion shell (29) are both located in the second cooling chamber (13), and the fixing block (28) separates the second cooling chamber (13).

9. A Roots vacuum unit for solvent recovery according to claim 8, characterized in that The rotating block (4) is provided with mirror image distributed pressure measuring cavities (30), the pressure measuring cavities (30) are slidably connected with pressure measuring pistons (31), the rotating block (4) is fixedly connected with center-symmetrically distributed shunt pipes (32), the shunt pipes (32) are used for connecting the pressure measuring cavities (30) with corresponding expansion shells (29), and the shunt pipes (32) are fixedly connected with corresponding fixed blocks (28).

10. A Roots vacuum unit for solvent recovery according to claim 9, characterized in that First reinforcing ribs (33) in linear array distribution and second reinforcing ribs (34) in linear array distribution are fixedly connected between the expansion shell (29) and the fixed block (28), the first reinforcing ribs (33) in linear array distribution and the second reinforcing ribs (34) in linear array distribution are staggered, the first reinforcing ribs (33) and the second reinforcing ribs (34) are all provided with uniformly distributed through holes, and the through holes on the first reinforcing ribs (33) and the second reinforcing ribs (34) are staggered.

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