Variable-pitch screw vacuum pump for chemical working conditions

Abstract

The invention discloses a variable-pitch screw vacuum pump for chemical working conditions, and relates to the technical field of screw vacuum pumps, the variable-pitch screw vacuum pump comprises a mounting rack, a driving unit, a detection unit, an adjusting unit and a backflow anticorrosion unit, the mounting rack is used for providing a mounting and fixing foundation, the driving unit is used for providing power, the detection unit is used for detecting flow fluctuation, and the adjusting unit is used for adjusting the backflow anticorrosion unit. The adjusting unit is used for adjusting buffering, the backflow anti-corrosion unit is used for preventing thread corrosion and even air exhaust, in the medium conveying process of the driving unit, after the detection unit detects that flow fluctuates, the adjusting unit is used for adjusting buffering, and impact caused by too large pressure is avoided; and meanwhile, in the medium conveying process, the backflow anti-corrosion unit is used for uniformly exhausting air and ensuring that screw teeth are corroded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of screw vacuum pumps, in particular to a variable pitch screw vacuum pump for chemical working conditions. BACKGROUND

[0002] As a kind of dry vacuum pump, screw vacuum pump is widely used in chemical production due to its advantages of no oil pollution, high pumping efficiency and wide range of vacuum degree, and is mainly used in chemical reaction kettle exhaust, solvent recovery, process gas transportation and other links. Chemical working conditions have significant complexity and harshness, and the medium is mostly mixed gas containing corrosive components (such as acid and alkali gas, chloride dust), and some media have condensability (such as hydrocarbon and alcohol vapor), and the pumping flow in the production process often fluctuates due to reaction progress and changes in feed amount, which puts high requirements on the adaptability, stability and durability of screw vacuum pumps.

[0003] Variable pitch screw vacuum pump realizes continuous compression of gas through gradual change of pitch, and has the characteristics of high compression ratio and stable exhaust compared with equal pitch structure, but there are still the following technical problems to be solved in the application of complex chemical working conditions:

[0004] Corrosive gas and dust in chemical medium are easy to come into direct contact with the surface of screw thread, causing chemical corrosion and physical wear of screw thread: on the one hand, corrosive medium will damage the passivation layer on the surface of screw thread, causing pitting and peeling, affecting the sealing performance of screw thread, and leading to the decrease of vacuum degree; on the other hand, the medium containing solid particles will aggravate the wear of screw thread working surface, shorten the service life of screw.

[0005] In chemical production, the pumping flow will fluctuate significantly with the reaction stage, feed amount and process parameter adjustment. The screw groove volume of the existing variable pitch screw vacuum pump is fixed, and it can only maintain the best pumping performance at the design rated flow: when the flow exceeds the rated value, the gas flow speed in the pump cavity is too fast, which is easy to produce vortex and pressure impact, leading to increased energy consumption and intensified vibration.

[0006] In the chemical pumping scene, the physical properties (such as density and viscosity) of the components of the mixed gas are quite different, and in the low pressure cavity of the existing variable pitch screw vacuum pump, the gas flow is in laminar state, and the components are difficult to mix fully, leading to too high medium concentration in local area, and easy to appear local overheating, uneven condensation and other problems in the compression process, affecting the pumping uniformity and running stability of the pump. SUMMARY

[0007] The purpose of the present application is to provide a variable pitch screw vacuum pump for chemical working conditions to solve the problems in the prior art.

[0008] To achieve the above purpose, the present application provides the following technical scheme:

[0009] The utility model provides a kind of variable pitch screw rod vacuum pump for chemical industry working condition, including mounting frame, controller is provided on the mounting frame, driving unit is provided on the mounting frame;

[0010] Adjusting unit is provided on the driving unit, and the adjusting unit expands and contracts action adjusts volume;

[0011] Detection unit is provided on the adjusting unit, the detection unit detects the flow pressure of medium into the adjusting unit, and the detection unit detects the flow pressure of medium.

[0012] Further, the adjusting unit includes a pump housing, a screw rod, a first end thread, a tail end thread, a memory spring, a slip ring and an elastic cone barrel, the pump housing is fixedly connected with the mounting box, the rotating rod is fixedly connected with the screw rod, the air inlet pipe is fixedly connected with the pump housing, the reset spring is fixedly connected with the pump housing, the screw rod is slidably connected with the first end thread, the first end thread is connected with the inner wall of the screw rod through the spring, the first end thread is abutted with the outer surface of the rigid end of the elastic cone barrel, the tail end thread is fixedly connected with the screw rod, the first end thread and the tail end thread have the same rotation direction, the pitch of the first end thread is larger than that of the tail end thread, one end of the memory spring is fixedly connected with the screw rod, the other end of the memory spring is fixedly connected with the slip ring, the slip ring is fixedly connected with the rigid end of the elastic cone barrel through the connecting rod, the elastic end of the elastic cone barrel is fixedly connected with the screw rod, and the slip ring is slidably connected with the rotating rod.

[0013] Further, the screw rod is provided with a one-way air inlet valve at one end of the exhaust pipe close to the mounting box, and is provided with a one-way air outlet valve at one end of the exhaust pipe away from the mounting box.

[0014] Further, the diameter of the rigid end of the elastic cone barrel is larger than that of the elastic end.

[0015] Further, the detection unit includes an air inlet pipe, a buffer plate, a conductive lifting lug, a straight rod and a reset spring, the memory spring is electrically connected with the conductive lifting lug, the air inlet pipe is provided with a moving groove, two elastic expansion plates are arranged in the moving groove, the buffer plate is slidably installed in the air inlet pipe, the buffer plate is fixedly connected with the conductive lifting lug, the conductive lifting lug is abutted with the expansion end of the elastic expansion plate, the conductive lifting lug is slidably connected with the straight rod, the reset spring is fixedly connected with the conductive lifting lug, and the air inlet pipe and the exhaust pipe on the mounting box are both provided with electromagnetic valves.

[0016] Further, the straight rod is provided with a driving coil, and the driving coil is close to the current input end at one end close to the horizontal ground.

[0017] Further, the adjusting unit is internally provided with a backflow corrosion prevention unit, which prevents corrosion of the adjusting unit and backflows of gas from the high-pressure end of the adjusting unit, and performs corrosion prevention and gas extraction on the adjusting unit.

[0018] Further, the backflow corrosion prevention unit comprises a sleeve, an elastic telescopic rod, a counterweight, an elastic contraction ring and a spiral rib, the sleeve is fixedly installed on the rotating rod, the fixed end of the elastic telescopic rod is fixedly installed on the sleeve, the telescopic end of the elastic telescopic rod is fixedly connected with the counterweight, the fixed end of the elastic contraction ring is fixedly installed on the inner wall of the screw rod, the telescopic end of the elastic contraction ring is provided with the spiral rib on the outer surface, the elastic contraction ring is filled with a corrosion prevention medium, the elastic contraction ring is connected with the first end screw thread through a conduit, and the elastic contraction ring is connected with the tail end screw thread through a conduit.

[0019] Further, the spiral rib is opposite in rotation direction to the first end screw thread.

[0020] Further, the driving unit comprises a driving motor, a shaft coupling, a driving gear, a driven gear, a mounting box and a rotating rod, the fixed end of the driving motor is fixedly installed on the mounting frame, the output end of the driving motor is in transmission connection with the driving gear through the shaft coupling, the driving gear is rotatably installed in the mounting box, the driving gear is in meshing connection with the driven gear, the driven gear is rotatably installed in the mounting box, the mounting box is fixedly installed on the mounting frame, one end of the rotating rod is fixedly connected with the driving gear, and the rotating rod is fixedly connected with the driven gear, and the mounting box is provided with an exhaust pipe.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1、The present application is through in the medium through the intake pipe flow process, when the pumping flow increases with the reaction stage, through the buffer plate to carry on the preliminary pressure relief after entering the pump shell, under the action of pressure, push the buffer plate to move down, so as to drive the electric lug compression reset spring along the straight rod to move down, with the electric lug descending distance increases, it indicates that the flow pressure of medium is larger at this time, the effective coil number of access circuit is reduced by the descending distance, the resistance of access circuit is reduced, so that the current received by the memory spring gradually increases, after the memory spring is electrified, it is contracted, so as to pull the sliding ring to the intake end of the pump shell, so as to drive the elastic cone barrel to contract, because the rigid end diameter of the elastic cone barrel is larger than the elastic end, so that the first end screw is gradually extruded upwards and slides upwards in the process of the elastic cone barrel moving, so as to make the first end screw expand outward and increase the volume, so as to adapt to the demand of large flow, avoid the internal airflow speed of pump cavity too fast, easy to produce vortex and pressure impact, cause damage to the pump body, after the flow is small, under the action of the restoring force of reset spring, push the electric lug to move up, increase the effective coil number of access circuit, increase the resistance of access circuit, so as to reduce the receiving current of memory spring, the memory spring resets and drives the sliding ring to move reversely, at this time, the first end screw slides down under the action of spring and resets, reduces the volume.

[0023] 2、The present application is through the high pressure gas in the pump cavity flows out to the exhaust pipe, under the action of pressure difference, a small amount of high pressure gas enters the screw rod through the one-way intake valve, then flows back to the low pressure cavity in the pump shell through the one-way exhaust valve, actively disturbs the airflow in the low pressure cavity, breaks the laminar flow, enhances the premixing effect of the inhaled medium, especially the mixed gas, and improves the extraction uniformity.

[0024] 3、The present application is through the rotation of the rotating rod drives the screw rod to rotate, under the action of centrifugal force, the counterweight pulls the elastic telescopic rod to elongate, the counterweight extrudes the spiral rib on the elastic contraction ring, so that the elastic contraction ring is pressed to slowly flow the anticorrosive medium in the inside into the surface of the first end screw and the tail end screw screw rib, forming a layer of dynamically updated protective film, this layer of film automatically fills the gap increased due to wear, and actively isolates the corrosive medium, realizes the corrosion prevention, if the micro bubbles have begun to condense, the high pressure area gas near the exhaust pipe in the pump shell enters the screw rod through the one-way intake valve, when the medium passes through the high-speed rotating spiral flow channel composed of spiral ribs, it is broken by strong shearing, delays or prevents the premature large gathering of liquid drops in the compression cavity, improves the processing capacity of the pump to the condensable gas. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the overall appearance structure schematic diagram of the present application;

[0026] Figure 2 It is the internal structure schematic diagram of the pump shell of the present application;

[0027] Figure 3 Figure 1 is a schematic diagram of the appearance structure of the driving unit of the present application;

[0028] Figure 4 Figure 2 is a schematic diagram of the structure of the detection unit of the present application;

[0029] Figure 5 Figure 3 is a schematic diagram of the structure of the screw, the screw thread at the head and the screw thread at the tail of the present application;

[0030] Figure 6 Figure 4 is a schematic diagram of the internal structure of the present application; Figure 5 Figure 5 is a schematic diagram of the internal structure of the present application;

[0031] Figure 7 Figure 6 is a schematic diagram of the internal structure of the present application; Figure 6 Figure 7 is a schematic diagram of the structure of the local enlarged view at A of the present application;

[0032] Figure 8 Figure 8 is a schematic diagram of the internal structure of the screw of the present application;

[0033] Figure 9 Figure 9 is a schematic diagram of the structure of the memory spring, the sliding ring and the elastic cone barrel of the present application;

[0034] Figure 10 Figure 10 is a schematic diagram of the appearance structure of the backflow corrosion prevention unit of the present application.

[0035] In the figure: 1, mounting frame; 2, driving unit; 21, driving motor; 22, shaft coupling; 23, driving gear; 24, driven gear; 25, mounting box; 26, rotating rod; 3, detection unit; 31, air inlet pipe; 32, buffer plate; 33, conductive lifting lug; 34, straight rod; 35, return spring; 4, adjustment unit; 41, pump shell; 42, screw; 43, screw thread at the head; 44, screw thread at the tail; 45, memory spring; 46, sliding ring; 47, elastic cone barrel; 5, backflow corrosion prevention unit; 51, sleeve; 52, elastic telescopic rod; 53, counterweight; 54, elastic contraction ring; 55, helical rib. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying 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. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0037] Embodiment: As shown in the figure, the present application provides a technical solution: Figures 1-10

[0038] As shown in the figure, Figure 1 , Figure 6 ​As shown, a variable pitch screw rod vacuum pump for chemical working conditions, comprising a mounting frame 1, the mounting frame 1 is provided with a controller, the mounting frame 1 is provided with a driving unit 2;

[0039] The driving unit 2 is provided with an adjusting unit 4, which adjusts the volume by expansion and contraction action;

[0040] The adjusting unit 4 is provided with a detection unit 3, which detects the flow pressure of the medium entering the adjusting unit 4, and the detection unit 3 detects the flow pressure of the medium.

[0041] As shown in Figure 2 、 Figure 5 、 Figures 7-9 The adjusting unit 4 comprises a pump shell 41, a screw rod 42, a first end thread 43, a tail end thread 44, a memory spring 45, a sliding ring 46 and an elastic cone barrel 47, the pump shell 41 is fixedly connected with the mounting box 25, the rotating rod 26 is fixedly connected with the screw rod 42, the air inlet pipe 31 is fixedly connected with the pump shell 41, the reset spring 35 is fixedly connected with the pump shell 41, the screw rod 42 is slidingly connected with the first end thread 43, the first end thread 43 is connected with the inner wall of the screw rod 42 through a spring, the first end thread 43 abuts against the outer surface of the rigid end of the elastic cone barrel 47, the tail end thread 44 is fixedly connected with the screw rod 42, the first end thread 43 and the tail end thread 44 have the same rotation direction, the pitch of the first end thread 43 is larger than that of the tail end thread 44, one end of the memory spring 45 is fixedly connected with the screw rod 42, the other end of the memory spring 45 is fixedly connected with the sliding ring 46, the sliding ring 46 is fixedly connected with the rigid end of the elastic cone barrel 47 through a connecting rod, the elastic end of the elastic cone barrel 47 is fixedly connected with the screw rod 42, and the sliding ring 46 is slidingly connected with the rotating rod 26.

[0042] After the memory spring 45 is electrified, it contracts to pull the sliding ring 46 to move towards the air inlet end of the pump shell 41, thereby driving the elastic cone barrel 47 to contract, since the diameter of the rigid end of the elastic cone barrel 47 is larger than that of the elastic end, the first end thread 43 is gradually pressed upwards to slide upwards during the movement of the elastic cone barrel 47, so that the first end thread 43 expands outward to increase the volume, thereby adapting to the demand for large flow, avoiding too fast airflow speed in the pump cavity, which is easy to produce vortex and pressure impact, causing damage to the pump body, after the flow becomes small, under the action of the restoring force of the reset spring 35, the conductive lug 33 is pushed to move upwards, the effective coil number of the connected circuit is increased, the resistance of the connected circuit is increased, thereby reducing the received current of the memory spring 45, the memory spring 45 is reset to drive the sliding ring 46 to move reversely, at this time, the first end thread 43 slides downwards to reset under the action of the spring, thereby reducing the volume.

[0043] As shown in Figure 5 The one-way air inlet valve is arranged at one end of the exhaust pipe close to the mounting box 25, and the one-way air outlet valve is arranged at one end of the exhaust pipe away from the mounting box 25.

[0044] In order to make the high pressure gas in the pump cavity to the exhaust pipe out of the process, by pressure difference, a small amount of high pressure gas through the one-way intake valve into the screw 42 inside, after the one-way exhaust valve back to the intake pipe 31 one end of the pump shell 41 inside the low pressure chamber, the initiative to disturb the airflow in the low pressure chamber, breaking the laminar flow, enhance the pre-mixed effect of the intake medium, especially mixed gas, improve the uniformity of the removal.

[0045] As shown in Figures 7-9 , the rigid end of the elastic cone barrel 47 is larger in diameter than the elastic end.

[0046] In order to make the elastic cone barrel 47 move gradually upward to extrude the first end screw 43 to slide upward, so as to increase the volume of the first end screw 43, thereby adapting to the demand of large flow.

[0047] As shown in Figure 4 , the detection unit 3 includes an intake pipe 31, a buffer plate 32, a conductive lug 33, a straight rod 34 and a reset spring 35, the memory spring 45 is electrically connected with the conductive lug 33, the intake pipe 31 is provided with a moving groove, the moving groove is provided with two elastic expansion plates, the buffer plate 32 is slidingly installed in the intake pipe 31, the buffer plate 32 is fixedly connected with the conductive lug 33, the conductive lug 33 is in abutment with the elastic expansion plate, the conductive lug 33 is slidingly connected with the straight rod 34, the reset spring 35 is fixedly connected with the conductive lug 33, and the intake pipe 31 and the exhaust pipe in the installation box 25 are both provided with electromagnetic valves.

[0048] As shown in Figure 4 , the straight rod 34 is provided with a drive coil, and the drive coil is close to the current input end of the horizontal ground.

[0049] In the process of medium flowing through the intake pipe 31, when the flow of the gas extraction increases with the reaction stage, the buffer plate 32 is used for the first pressure relief, and then enters the pump shell 41 under the action of pressure, thereby driving the buffer plate 32 to move downward, so as to drive the conductive lug 33 to compress the reset spring 35 while moving downward along the straight rod 34. With the increase of the descending distance of the conductive lug 33, it indicates that the flow pressure of the medium at this time is larger, and the descending distance increases, so that the effective coil number of the connected circuit is reduced, and the resistance of the connected circuit is reduced, so that the current received by the memory spring 45 gradually increases.

[0050] As shown in Figure 6 , the adjustment unit 4 is provided with a backflow corrosion prevention unit 5, which prevents the corrosion of the adjustment unit 4 and the backflow of the gas in the high pressure end of the adjustment unit 4, and the backflow corrosion prevention unit 5 prevents the corrosion of the adjustment unit 4 and the gas extraction.

[0051] As shown in Figure 8 , Figure 10As shown, the backflow corrosion prevention unit 5 includes a sleeve 51, an elastic telescopic rod 52, a counterweight 53, an elastic contraction ring 54 and a helical rib 55. The sleeve 51 is fixedly installed on the rotating rod 26. The fixed end of the elastic telescopic rod 52 is fixedly installed on the sleeve 51. The telescopic end of the elastic telescopic rod 52 is fixedly connected with the counterweight 53. The fixed end of the elastic contraction ring 54 is fixedly installed on the inner wall of the screw rod 42. The telescopic end of the elastic contraction ring 54 is provided with the helical rib 55 on the outer surface. The elastic contraction ring 54 is filled with a corrosion prevention medium. The elastic contraction ring 54 is connected with the first end screw thread 43 and the tail end screw thread 44 through a conduit.

[0052] During the rotation of the rotating rod 26 and the screw rod 42, the counterweight 53 pulls the elastic telescopic rod 52 to elongate under the action of centrifugal force. The counterweight 53 extrudes the helical rib 55 on the elastic contraction ring 54, so that the elastic contraction ring 54 is pressed to slowly flow the corrosion prevention medium in the inside to the surface of the first end screw thread 43 and the tail end screw thread 44 through the conduit, forming a dynamically updated protective film. The film automatically fills the gap caused by abrasion and actively isolates the corrosive medium, thereby achieving corrosion prevention. If the micro-bubbles that have begun to condense are in the high-pressure area near the exhaust pipe in the pump shell 41, the gas enters the inside of the screw rod 42 through the one-way inlet valve. When the medium passes through the helical flow channel composed of the helical rib 55 at high speed, it is broken by strong shearing. The premature large-scale aggregation of liquid drops in the compression chamber is delayed or prevented, and the processing capacity of the pump for condensable gas is improved.

[0053] As shown in Figure 5 , Figure 10 , the rotation direction of the helical rib 55 is opposite to that of the first end screw thread 43.

[0054] When the screw rod 42 rotates, the external first end screw thread 43 and the tail end push the gas to move towards the exhaust end. The macroscopic flow field direction is consistent with the rotation direction of the screw thread. The gas in the internal reverse helical flow channel flows in the opposite direction under the action of pressure difference. The two flows that are closely adjacent in space and in opposite directions generate a large shear rate at the interface. For the condensable micro-bubbles that enter the internal flow channel with backflow, they not only suffer shearing from the flow channel wall, but also are torn by the strong reverse shearing flow field. The micro-bubbles are placed in a high-efficiency dynamic shearing field, which can extremely completely break them into smaller sizes, thereby greatly increasing the surface area of the phase change core. This is much stronger than the breaking effect caused by the same direction flow channel or simple throttling, significantly delaying the aggregation and growth of the condensed liquid drops.

[0055] As shown in Figure 2 , Figure 3As shown, the driving unit 2 comprises a driving motor 21, a shaft coupling 22, a driving gear 23, a driven gear 24, a mounting box 25 and a rotating rod 26, the fixed end of the driving motor 21 is fixedly installed on the mounting frame 1, the output end of the driving motor 21 is in transmission connection with the driving gear 23 through the shaft coupling 22, the driving gear 23 is rotatably installed in the mounting box 25, the driving gear 23 is in meshing connection with the driven gear 24, the driven gear 24 is rotatably installed in the mounting box 25, the mounting box 25 is fixedly installed on the mounting frame 1, one end of the rotating rod 26 is fixedly connected with the driving gear 23, the rotating rod 26 is fixedly connected with the driven gear 24, and an exhaust pipe is arranged on the mounting box 25.

[0056] The controller controls the driving motor 21 to start, under the transmission action of the shaft coupling 22, the driving gear 23 is driven to rotate, thereby driving the driven gear 24 in meshing connection with the driving gear 23 to rotate, thereby driving the rotating rod 26 to rotate, the screw rod 42 is driven to rotate, under the pushing action of the first end screw thread 43 and the tail end screw thread 44, the medium flowing into the pump shell 41 is conveyed to the exhaust port.

[0057] The working principle of the present application is as follows:

[0058] The controller controls the driving motor 21 to start, under the transmission action of the shaft coupling 22, the driving gear 23 is driven to rotate, thereby driving the driven gear 24 in meshing connection with the driving gear 23 to rotate, thereby driving the rotating rod 26 to rotate, the screw rod 42 is driven to rotate, under the pushing action of the first end screw thread 43 and the tail end screw thread 44, the medium flowing into the pump shell 41 is conveyed to the exhaust port.

[0059] In the flowing process of the medium through the air inlet pipe 31, when the air extraction flow rate increases with the reaction stage, after the initial pressure relief through the buffer plate 32, the medium enters the pump shell 41, under the pressure action, the buffer plate 32 is pushed to move downward, thereby driving the conductive lifting lug 33 to compress the reset spring 35 and move downward along the straight rod 34, with the increase of the descending distance of the conductive lifting lug 33, it indicates that the flow pressure of the medium at this time is larger, the increase of the descending distance reduces the effective coil number of the connected circuit, the resistance of the connected circuit is reduced, thereby the current received by the memory spring 45 is gradually increased.

[0060] When the memory spring 45 is electrified, it contracts, thereby pulling the sliding ring 46 to move towards the air inlet end of the pump shell 41, and driving the elastic cone barrel 47 to contract. Since the rigid end of the elastic cone barrel 47 has a larger diameter than the elastic end, the elastic cone barrel 47 gradually presses the first end screw thread 43 upwards during the movement of the elastic cone barrel 47, so that the first end screw thread 43 expands outward to increase the volume, thereby adapting to the demand of large flow, avoiding that the airflow speed in the pump cavity is too fast, which is easy to produce vortex and pressure impact, causing damage to the pump body. When the flow becomes small, under the restoring force of the reset spring 35, the conductive lug 33 is pushed to move upwards, the effective coil number of the access circuit is increased, the resistance of the access circuit is increased, thereby reducing the received current of the memory spring 45, and the memory spring 45 is reset to drive the sliding ring 46 to move reversely, at this time, the first end screw thread 43 slides downwards under the action of the spring to reset and reduce the volume.

[0061] During the rotation of the rotating rod 26 to drive the screw rod 42 to rotate, under the action of centrifugal force, the counterweight 53 pulls the elastic expansion rod 52 to elongate, the counterweight 53 presses the spiral rib 55 on the elastic contraction ring 54, so that the elastic contraction ring 54 is pressed to slowly flow the anticorrosive medium in the inside through the conduit to the surface of the screw thread of the first end screw thread 43 and the tail end screw thread 44, forming a dynamically updated protective film. This film automatically fills the gap that is increased due to wear, and actively isolates the corrosive medium, achieving corrosion prevention. If the micro-bubbles that have begun to condense, the gas in the high-pressure area near the exhaust pipe in the pump shell 41 enters the inside of the screw rod 42 through the one-way air inlet valve, when the medium passes through the spiral flow channel composed of the spiral rib 55 at high speed, it is broken by strong shearing, delaying or preventing the premature large aggregation of liquid drops in the compression cavity, and improving the processing capacity of the pump for condensable gas.

[0062] It is apparent for those skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the claims. Any reference signs in the claims should not be considered as limiting the claims involved.

Claims

1. A variable pitch screw vacuum pump for chemical processing, characterized in that: The variable pitch screw vacuum pump for chemical working conditions includes a mounting frame (1), a controller is provided on the mounting frame (1), and a drive unit (2) is provided on the mounting frame (1). The drive unit (2) is provided with an adjustment unit (4), which performs expansion and contraction actions to adjust the volume; The adjustment unit (4) is provided with a detection unit (3), which detects the flow rate and pressure of the medium entering the adjustment unit (4).

2. The variable pitch screw vacuum pump for chemical processing as described in claim 1, characterized in that: The adjustment unit (4) includes a pump housing (41), a screw (42), a first end thread (43), a last end thread (44), a memory spring (45), a slip ring (46), and an elastic cone (47). The pump housing (41) is fixedly connected to the mounting box (25), the rotating rod (26) is fixedly connected to the screw (42), the air inlet pipe (31) is fixedly connected to the pump housing (41), the return spring (35) is fixedly connected to the pump housing (41), the screw (42) is slidably connected to the first end thread (43), the first end thread (43) is connected to the inner wall of the screw (42) through the spring, and the first end thread (43) is connected to the spring. The outer surface of the rigid end of the elastic cone barrel (47) abuts against the screw (42) at the tail end. The screw thread (44) at the tail end is fixedly connected to the screw (42). The screw thread (43) at the head end and the screw thread (44) at the tail end have the same direction of rotation. The pitch of the screw thread (43) at the head end is larger than the pitch of the screw thread (44) at the tail end. One end of the memory spring (45) is fixedly connected to the screw (42). The other end of the memory spring (45) is fixedly connected to the slip ring (46). The slip ring (46) is fixedly connected to the rigid end of the elastic cone barrel (47) through a connecting rod. The elastic end of the elastic cone barrel (47) is fixedly connected to the screw (42). The slip ring (46) is slidably connected to the rotating rod (26).

3. A variable pitch screw vacuum pump for chemical processing as described in claim 2, characterized in that: A one-way air intake valve is provided at the end of the screw (42) near the exhaust pipe of the mounting box (25), and a one-way exhaust valve is provided at the end of the screw (42) away from the exhaust pipe of the mounting box (25).

4. A variable pitch screw vacuum pump for chemical processing as described in claim 2, characterized in that: The diameter of the rigid end of the elastic cone (47) is larger than that of the elastic end.

5. A variable pitch screw vacuum pump for chemical processing as described in claim 4, characterized in that: The detection unit (3) includes an air inlet pipe (31), a buffer plate (32), a conductive lug (33), a straight rod (34), and a return spring (35). The memory spring (45) is electrically connected to the conductive lug (33). The air inlet pipe (31) is provided with a moving groove, and two elastic telescopic plates are provided in the moving groove. The buffer plate (32) is slidably installed in the air inlet pipe (31). The buffer plate (32) is fixedly connected to the conductive lug (33). The conductive lug (33) abuts against the telescopic end of the elastic telescopic plate. The conductive lug (33) is slidably connected to the straight rod (34). The return spring (35) is fixedly connected to the conductive lug (33). Electromagnetic valves are provided in both the air inlet pipe (31) and the exhaust pipe on the mounting box (25).

6. A variable pitch screw vacuum pump for chemical processing as described in claim 5, characterized in that: A drive coil is provided on the straight rod (34), and the end of the drive coil closest to the horizontal ground is the current input end.

7. A variable pitch screw vacuum pump for chemical processing as described in claim 2, characterized in that: The adjustment unit (4) is equipped with a reflux anti-corrosion unit (5). The reflux anti-corrosion unit (5) prevents the adjustment unit (4) from corroding while refluxing part of the gas at the high-pressure end of the adjustment unit (4). The reflux anti-corrosion unit (5) performs anti-corrosion and gas extraction on the adjustment unit (4).

8. A variable pitch screw vacuum pump for chemical processing as described in claim 7, characterized in that: The reflux anti-corrosion unit (5) includes a sleeve (51), an elastic telescopic rod (52), a counterweight (53), an elastic shrink ring (54), and a spiral rib (55). The sleeve (51) is fixedly installed on the rotating rod (26). The fixed end of the elastic telescopic rod (52) is fixedly installed on the sleeve (51). The telescopic end of the elastic telescopic rod (52) is fixedly connected to the counterweight (53). The fixed end of the elastic shrink ring (54) is fixedly installed on the inner wall of the screw (42). The outer surface of the telescopic end of the elastic shrink ring (54) is provided with a spiral rib (55). The elastic shrink ring (54) is filled with an anti-corrosion medium. The elastic shrink ring (54) is connected to the first end thread (43) through a conduit. The elastic shrink ring (54) is connected to the tail end thread (44) through a conduit.

9. A variable pitch screw vacuum pump for chemical processing as described in claim 8, characterized in that: The spiral direction of the spiral rib (55) is opposite to that of the first end thread (43).

10. A variable pitch screw vacuum pump for chemical processing as described in claim 1, characterized in that: The drive unit (2) includes a drive motor (21), a coupling (22), a drive gear (23), a driven gear (24), a mounting box (25), and a rotating rod (26). The fixed end of the drive motor (21) is fixedly mounted on the mounting frame (1). The output end of the drive motor (21) is connected to the drive gear (23) through the coupling (22). The drive gear (23) is rotatably mounted in the mounting box (25). The drive gear (23) meshes with the driven gear (24). The driven gear (24) is rotatably mounted in the mounting box (25). The mounting box (25) is fixedly mounted on the mounting frame (1). One end of the rotating rod (26) is fixedly connected to the drive gear (23). The rotating rod (26) is fixedly connected to the driven gear (24). An exhaust pipe is provided on the mounting box (25).

Images