Three-screw pump for conveying marine low-sulfur diesel oil

Abstract

The utility model relates to the technical field of ship fuel oil conveying, in particular to a three-screw pump for conveying marine low-sulfur diesel oil, which comprises a pump body, the pump body comprises a suction cavity arranged along a first direction and a screw cavity arranged at one end of the suction cavity and communicated with the suction cavity, and one side of the pump body is provided with an oil inlet and an oil outlet; the oil inlet is communicated with the suction cavity through an oil inlet channel arranged in the first direction, the oil inlet channel is located on the side, close to the screw cavity, of the suction cavity, and the oil outlet is connected with the screw cavity through an obliquely-arranged oil outlet channel. The screw rod part comprises a driving screw rod and two driven screw rods, the driving screw rod and the driven screw rods are provided with smooth connecting sections and spiral sections with threads, the driving screw rod and the driven screw rods can be rotationally connected with the screw rod cavity in the mode of rotating around the axes of the driving screw rod and the driven screw rods, and the spiral sections of the driven screw rods are meshed with the spiral section of the driving screw rod. The device has the advantage of being small in size.

Description

Technical Field

[0001] This application relates to the technical field of ship fuel oil transportation, and in particular to a three-screw pump for marine low-sulfur diesel oil transportation. Background Art

[0002] In the shipbuilding industry, pumping equipment is crucial for the stable supply of fuel oil. With the gradual strengthening of environmental protection regulations, low-sulfur diesel oil, as a more environmentally friendly fuel option, is increasingly used on ships. However, the transportation of low-sulfur diesel oil not only requires efficient pumping equipment but also demands that the equipment be structurally compact and space-saving to adapt to the limited space conditions on ships.

[0003] Although traditional fuel pumps can meet the basic fuel transportation requirements, they show their limitations when faced with the transportation of low-sulfur diesel oil and the space limitations on ships. Especially in terms of the size of the pump body, traditional design solutions are often too large, not only occupying valuable ship space but also potentially affecting the layout of other equipment and systems. Summary of the Utility Model

[0004] In order to reduce the size of the pump for transporting diesel oil, this application provides a three-screw pump for marine low-sulfur diesel oil transportation.

[0005] The three-screw pump for marine low-sulfur diesel oil transportation provided by this application adopts the following technical solutions:

[0006] A three-screw pump for marine low-sulfur diesel oil transportation includes a pump body. The pump body includes a suction chamber arranged along a first direction and a screw chamber provided at one end of the suction chamber and communicating with the suction chamber. An oil inlet and an oil outlet are provided on one side of the pump body. The oil inlet is connected to the suction chamber through an oil inlet passage arranged along the first direction. The oil inlet passage is located on the side of the suction chamber close to the screw chamber. The oil outlet is connected to the screw chamber through an obliquely arranged oil outlet passage; a screw part, the screw part includes a driving screw and two driven screws. The driving screw and the driven screws both have a smooth connecting section and a helical section with threads. The driving screw and the driven screws are both rotatably connected to the screw chamber around their own axes, and the helical section of the driven screw meshes with the helical section of the driving screw.

[0007] By adopting the above technical solutions, the obliquely arranged oil outlet passage can make the position where the oil outlet passage communicates with the screw chamber as close as possible to one end of the connecting section of the driving screw close to the helical section, thereby reducing the axial dimension of the pump body. The suction chamber provided at one end of the screw chamber can reduce the radial dimension of the pump body. The oil inlet passage provided on the side of the suction chamber close to the screw chamber can further reduce the axial dimension of the pump body, thus playing a role in reducing the size of the pump body and occupying less space.

[0008] Optionally, the screw chamber includes a main screw chamber arranged along the first direction and two auxiliary screw chambers arranged along the first direction. The auxiliary screw chambers are respectively arranged on both sides of the main screw chamber. The driving screw is arranged in the main screw chamber, the driven screw is arranged in the auxiliary screw chamber, and the oil outlet channel is communicated with the main screw chamber.

[0009] By adopting the above technical solution, the screw chamber plays a role in limiting the screw, restricting the translational freedom and rotational freedom of the screw in the radial direction.

[0010] Optionally, a positioning flange is provided on the connecting section of the driving screw, and a positioning groove matching with the positioning flange is provided on the connecting section of the driven screw.

[0011] By adopting the above technical solution, the mutual cooperation of the positioning flange and the positioning groove further defines the relative position of the driven screw and the driving screw in the axial direction, preventing the driven screw from generating relative movement with the driving screw in the axial direction.

[0012] Optionally, a pump front flange is provided at one end of the screw chamber away from the suction chamber. The connecting section of the driving screw penetrates through the pump front flange and is rotatably connected to the pump front flange. A lubricating chamber is provided on one side of the pump front flange close to the pump body. An oil replenishing channel communicated with the lubricating chamber is provided on the pump front flange. The lubricating chamber is isolated from the screw chamber by a first sealing assembly, and a second sealing assembly is provided between the driving screw and the pump front flange.

[0013] By adopting the above technical solution, the pump front flange can limit the axial movement freedom of the driving screw. Since there is relative rotation between the driving screw and both the pump body and the pump front flange, the lubricating chamber can play a role in containing lubricating oil to reduce the friction between the driving screw and the pump front flange and the pump body. The oil replenishing channel communicated with the lubricating chamber is used to replenish lubricating oil into the lubricating chamber. The first sealing assembly is used to isolate the lubricating chamber and the screw chamber, and the second sealing assembly is used to prevent lubricating oil from leaking from the connection between the driving screw and the pump front flange.

[0014] Optionally, the first sealing assembly includes a first oil retaining ring, a second oil retaining ring and a ball bearing. The first oil retaining ring and the ball bearing are sequentially arranged on the driving screw along the first direction. The second oil retaining ring is arranged on the driven screw and abuts against the first oil retaining ring.

[0015] By adopting the above technical solution, the oil retaining ring plays a role in isolating the lubricating chamber and the screw chamber. The ball bearing can reduce the friction between the driving screw and the pump body on the one hand, and can also consume the oil leaking from the screw chamber on the other hand.

[0016] Optionally, the second sealing assembly includes a mechanical seal and a skeleton seal, and the mechanical seal and the skeleton seal are sequentially arranged on the driving screw along the first direction.

[0017] By adopting the above technical solution, the mechanical seal can prevent lubricating oil from leaking at the connection between the driving screw and the front flange of the pump. The skeleton seal not only prevents the leakage of lubricating oil but also plays a role in dust prevention, preventing external dust, impurities, etc. from entering the lubrication chamber.

[0018] Optionally, the number of the oil replenishing channels is at least one, and a plug is provided at one end of the oil replenishing channel away from the lubrication chamber.

[0019] By adopting the above technical solution, the plug can be used as a switch for the oil replenishing channel. Multiple oil replenishing channels ensure the stability and continuous oil supply of the lubrication system, which is beneficial to the long-term stable operation of the pump.

[0020] Optionally, the pump body further includes a pressure relief chamber, and the pressure relief chamber includes a high-pressure chamber and a pressure relief chamber that are communicated with each other. The high-pressure chamber is communicated with the screw chamber through a pressure relief channel, the pressure relief chamber is communicated with the suction chamber, and a pressure relief component for controlling the on-off between the high-pressure chamber and the pressure relief chamber is provided in the pressure relief chamber.

[0021] By adopting the above technical solution, the pressure relief chamber can effectively balance the pressure in the screw chamber, avoiding problems such as equipment damage or excessive oil output caused by too high pressure.

[0022] Optionally, the inner diameter of the high-pressure chamber is smaller than that of the pressure relief chamber. The pressure relief component includes a valve core, a spring, a valve seat, and a pressure rod. The valve core is connected to the valve seat through the spring. The valve core is used to cooperate with the high-pressure chamber. The valve seat is threadedly connected to the pressure rod. A positioning pin perpendicular to the axis of the pressure relief chamber is provided on one side of the valve seat. A pin slot is provided on the pump body along the axis direction of the pressure relief chamber and is matched with the positioning pin. The pressure rod is connected to the pump body in a manner that can rotate around its own axis.

[0023] By adopting the above technical solution, the spring can give the valve core a force pointing to the high-pressure chamber to suppress the force of the diesel oil in the high-pressure chamber pointing to the pressure relief chamber on the valve core, so that the valve core can block the connection position between the high-pressure chamber and the pressure relief chamber. When the pressure in the high-pressure chamber gradually increases, the force of the diesel oil in the high-pressure chamber pointing to the pressure relief chamber on the valve core also gradually increases, so that this force can overcome the force of the spring pointing to the high-pressure chamber, push the valve core away from the connection position between the high-pressure chamber and the pressure relief chamber, and make the high-pressure chamber and the pressure relief chamber communicate with each other, thereby realizing pressure relief.

[0024] Optionally, a rear cover is detachably connected to one end of the suction chamber away from the screw chamber. A through hole matching the pressure rod is provided on the rear cover, and a sealing ring is provided between the pressure rod and the rear cover.

[0025] By adopting the above technical solution, the rear cover detachably connected to the pump body is convenient for the staff to perform maintenance.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. The axially inclined oil outlet channel and the parallel oil inlet channel can reduce the axial dimension of the pump body. By placing the suction chamber at one end of the screw chamber to directly connect the suction chamber and the screw chamber, the radial dimension of the pump body can be reduced, realizing the miniaturization of the pumping equipment and saving space on the ship.

[0028] 2. The positioning flange and positioning groove with a hanging connection design can limit the axial displacement between the driving screw and the driven screw, improving the running stability of the pump.

[0029] 3. The setting of the lubricating chamber and the oil replenishing channel improves the lubrication effect of the screw part and extends the service life of the pump.

[0030] 4. The pressure relief chamber and the pressure relief components inside it can effectively balance the pressure in the pump body, enhancing the safety and reliability of the pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of a three-screw pump for marine low-sulfur diesel oil transportation provided by an embodiment of the present application;

[0032] Figure 2 is a schematic internal structure diagram of a three-screw pump for marine low-sulfur diesel oil transportation provided by an embodiment of the present application;

[0033] Figure 3 is a schematic structural diagram of the pump body provided by an embodiment of the present application;

[0034] Figure 4 is an exploded structural diagram of a three-screw pump for marine low-sulfur diesel oil transportation provided by an embodiment of the present application;

[0035] Figure 5 is Figure 4 a partial enlarged view of part A in

[0036] Description of the reference numerals: 1 - pump body; 101 - suction chamber; 102 - screw chamber; 1021 - main screw chamber; 1022 - auxiliary screw chamber; 103 - oil inlet; 1031 - oil inlet passage; 104 - oil outlet; 1041 - oil outlet passage; 2 - driving screw; 201 - positioning flange; 3 - driven screw; 301 - positioning groove; 4 - pump front flange; 401 - lubrication chamber; 402 - oil replenishing passage; 403 - sealing ring; 5 - first oil retaining ring; 6 - second oil retaining ring; 7 - ball bearing; 8 - bearing retaining ring; 9 - mechanical seal; 10 - skeleton seal; 11 - skeleton retaining ring; 12 - pressure relief chamber; 1201 - high-pressure chamber; 1202 - pressure relief passage; 1203 - pressure relief chamber; 13 - valve core; 14 - spring; 15 - valve seat; 16 - pressure rod; 17 - positioning pin; 18 - pin slot; 19 - rear cover; 20 - sealing ring; 21 - gasket; 22 - plug; 23 - bolt; 24 - keyway; 25 - key; 26 - inspection passage. Detailed implementation manners

[0037] The following further elaborates on this application in conjunction with the attached Figures 1-5 drawings.

[0038] In this application, unless otherwise stated, the orientation terms such as "inside, outside" refer to the contour of the corresponding component itself, and the orientation term such as the first direction refers to Figure 1 the direction pointed by x in

[0039] This application embodiment discloses a three-screw pump for marine low-sulfur diesel oil transportation.

[0040] As Figure 1 shown in Figure 2 and

[0041] , the three-screw pump for marine low-sulfur diesel oil transportation includes a pump body 1. The pump body 1 includes a suction chamber 101 arranged along the first direction and a screw chamber 102 provided at one end of the suction chamber 101 and communicating with the suction chamber 101. An oil inlet 103 and an oil outlet 104 are provided on one side of the pump body 1. The oil inlet 103 is connected to the suction chamber 101 through an oil inlet passage 1031 arranged along the first direction. The oil inlet passage 1031 is located on the side of the suction chamber 101 close to the screw chamber 102. The oil outlet 104 is connected to the screw chamber 102 through an obliquely arranged oil outlet passage 1041; a screw part, the screw part includes a driving screw 2 and two driven screws 3. The driving screw 2 and the driven screws 3 both have a smooth connecting section and a threaded spiral section. The driving screw 2 and the driven screws 3 are both rotatably connected to the screw chamber 102 around their own axes, and the spiral section of the driven screw 3 meshes with the spiral section of the driving screw 2.By using the obliquely arranged oil outlet channel 1041, the position where the oil outlet channel 1041 communicates with the screw cavity 102 can be made as close as possible to one end of the connection section of the driving screw 2 near the spiral section, thereby reducing the axial dimension of the pump body 1. The suction cavity 101 provided at one end of the screw cavity 102 can reduce the radial dimension of the pump body 1, and the oil inlet channel 1031 provided on the side of the suction cavity 101 close to the screw cavity 102 can further reduce the axial dimension of the pump body 1, thus playing a role in reducing the size of the pump body 1 and occupying less space.

[0042] As Figure 2 and Figure 3 shown, the screw cavity 102 includes a main screw chamber 1021 arranged in the first direction and two auxiliary screw chambers 1022 arranged in the first direction. The auxiliary screw chambers 1022 are respectively arranged on both sides of the main screw chamber 1021. The driving screw 2 is arranged in the main screw chamber 1021, and the driven screw 3 is arranged in the auxiliary screw chamber 1022. The oil outlet channel 1041 communicates with the main screw chamber 1021. The main screw chamber 1021 and the auxiliary screw chambers 1022 are simultaneously communicated with the suction cavity 101. The screw chamber plays a role in limiting the screw, restricting the translational freedom and rotational freedom of the screw in the radial direction.

[0043] The spiral section of the driving screw 2 meshes with the spiral section of the driven screw 3. The spiral section of the driving screw 2 cooperates with the inner surface of the main screw chamber 1021, and the spiral section of the driven screw 3 cooperates with the inner surface of the auxiliary screw chamber 1022. When the driving screw 2 rotates, the driven screw 3 rotates together with the driving screw 2 under the meshing action, so that several dynamic seal chambers are formed between the two ends of the spiral section of the driving screw 2 and the spiral section of the driven screw 3. These dynamic seal chambers will continuously axially move the oil from the suction cavity 101 to the screw cavity 102 and gradually boost the pressure of the oil being transported until the junction of the connection section and the spiral section of the driving screw 2. Thus, a continuous, stable and axially moving pressure oil flow is formed. Finally, it is discharged from the oil outlet channel 1041 out of the screw cavity 102.

[0044] As Figure 4 and Figure 5 shown, a positioning flange 201 is provided on the connection section of the driving screw 2, and a positioning groove 301 cooperating with the positioning flange 201 is provided on the connection section of the driven screw 3. The mutual cooperation of the positioning flange 201 and the positioning groove 301 further limits the relative position of the driven screw 3 and the driving screw 2 in the axial direction, preventing the driven screw 3 from generating relative movement with the driving screw 2 in the axial direction.

[0045] As Figure 2 and Figure 4As shown in the figure, a pump front flange 4 is provided at one end of the screw cavity 102 away from the suction cavity 101. The connecting section of the driving screw 2 penetrates through the pump front flange 4 and is rotatably connected to the pump front flange 4. A lubrication cavity 401 is provided on the side of the pump front flange 4 close to the pump body 1. An oil replenishing channel 402 communicating with the lubrication cavity 401 is provided on the pump front flange 4. The lubrication cavity 401 is isolated from the screw cavity 102 by a first sealing assembly. A second sealing assembly is provided between the driving screw 2 and the pump front flange 4. In this application, both the oil inlet 103 and the oil outlet 104 are provided on one side of the pump body 1, so that the SAE standard flange can be used as the pump front flange 4 to be directly connected to the pump body 1, reducing the radial dimension. In some other embodiments, the pump front flange 4 can be fixedly connected to the pump body 1. In this embodiment, the pump front flange 4 is detachably connected to the pump body 1 by bolts 23, which is convenient for subsequent maintenance. At the same time, in order to prevent the lubricating oil in the lubrication cavity 401 from leaking from the connection between the pump front flange 4 and the pump body 1, a sealing ring 403 can also be provided between the pump front flange 4 and the pump body 1.

[0046] In addition, the pump front flange 4 can limit the axial movement freedom of the driving screw 2. Since the driving screw 2 rotates relative to both the pump body 1 and the pump front flange 4, the lubrication cavity 401 can play a role in containing the lubricating oil that reduces the friction between the driving screw 2 and the pump front flange 4 and the pump body 1. The oil replenishing channel 402 communicating with the lubrication cavity 401 is used to replenish lubricating oil into the lubrication cavity 401. The first sealing assembly is used to isolate the lubrication cavity 401 and the screw cavity 102. The second sealing assembly is used to prevent the lubricating oil from leaking from the connection between the driving screw 2 and the pump front flange 4. In order to facilitate the rotation of the driving screw 2, a keyway 24 is provided on the part of the driving screw 2 outside the pump body 1, and a key 25 is provided in the keyway 24.

[0047] As Figure 2 and Figure 4As shown in the figure, the first sealing assembly includes a first oil baffle ring 5, a second oil baffle ring 6 and a ball bearing 7. The first oil baffle ring 5 and the ball bearing 7 are sequentially arranged on the driving screw 2 along the first direction. The second oil baffle ring 6 is arranged on the driven screw 3, and the second oil baffle ring 6 abuts against the first oil baffle ring 5. Since the screw cavity 102 is often in a high-pressure state compared with the lubrication cavity 401, usually the oil in the screw cavity 102 leaks into the lubrication cavity 401. The first oil baffle ring 5 serves to isolate the lubrication chamber and the main screw chamber 1021 of the screw cavity 102, and the second oil baffle ring 6 serves to isolate the lubrication chamber and the auxiliary screw chamber 1022 of the screw cavity 102. The mutually abutting first oil baffle ring 5 and second oil baffle ring 6 can prevent oil from leaking at the connection between the main screw chamber 1021 and the auxiliary screw chamber 1022. In this embodiment, the first oil baffle ring 5 is integrally formed with the driving screw 2, and the second oil baffle ring 6 is integrally formed with the driven screw 3. The positioning flange 201 is arranged on the first oil baffle ring 5 in the negative direction of the first direction, and the positioning groove 301 can be arranged at the second oil baffle ring 6. On the one hand, the ball bearing 7 can reduce the friction between the driving screw 2 and the pump body 1. On the other hand, part of the oil that is not intercepted by the first oil baffle ring 5 and the second oil baffle ring 6 reaches between the inner ring and the outer ring of the ball bearing 7 and is consumed for lubrication.

[0048] As Figure 2 and Figure 4 shown in the figure, the second sealing assembly includes a mechanical seal 9 and a skeleton seal 10. The mechanical seal 9 and the skeleton seal 10 are sequentially arranged on the driving screw 2 along the first direction. The mechanical seal 9 refers to a device that prevents fluid leakage, which is composed of at least a pair of end faces perpendicular to the rotation axis. Under the action of fluid pressure and the elastic force of the compensation mechanism and with the cooperation of auxiliary seals, this pair of end faces remain in contact and slide relative to each other. The function of the skeleton seal 10 is to isolate the components that need to be lubricated in the transmission components from the external environment, so as not to let the lubricating oil leak, and to prevent external dust, impurities, etc. from entering the equipment. The mechanical seal 9 and the skeleton seal 10 are both conventional technical means in the art, and their specific structures are not described in this application. In addition, it can be understood that a positioning step for positioning the ball bearing 7 is provided at the pump body 1, a positioning step for positioning the mechanical seal 9 and the skeleton seal 10 is provided at the pump front flange 4, a bearing retaining ring 8 for preventing the axial movement of the ball bearing 7 is provided at the ball bearing 7, and a skeleton retaining ring 11 for preventing the axial movement of the skeleton seal 10 is provided at the skeleton seal 10. Setting the positioning step for positioning and setting the retaining ring for preventing axial movement are common general knowledge in the art, and this application does not elaborate on this.

[0049] As Figure 1 and Figure 4As shown, the number of oil replenishing channels 402 is at least one. A plug 22 is provided at one end of the oil replenishing channel 402 away from the lubricating chamber 401. The plug 22 can be used as a switch for the oil replenishing channel 402. Multiple oil replenishing channels 402 ensure the stability and continuous oil supply of the lubrication system, which is beneficial to the long-term stable operation of the pump.

[0050] In addition, multiple inspection channels 26 can also be provided on the pump body 1. For example, an inspection channel 26 communicating with the screw chamber 102, or an inspection channel 26 communicating with the suction chamber 101. A plug 22 can also be provided at one end of the inspection channel 26 away from the pump body 1 to be used as a switch for the inspection channel 26.

[0051] As Figure 2 and Figure 4 As shown, the pump body 1 further includes a pressure relief chamber 12. The pressure relief chamber 12 includes a high-pressure chamber 1201 and a pressure relief chamber 1203 that communicate with each other. The inner diameter of the high-pressure chamber 1201 is smaller than that of the pressure relief chamber 1203. The high-pressure chamber 1201 is connected to the screw chamber 102 through a pressure relief channel 1202. The pressure relief chamber 1203 is connected to the suction chamber 101. A pressure relief component for controlling the on-off between the high-pressure chamber 1201 and the pressure relief chamber 1203 is provided in the pressure relief chamber 1203. Specifically, the pressure relief component includes a valve core 13, a spring 14, a valve seat 15, and a pressure rod 16. The valve core 13 is connected to the valve seat 15 through the spring 14. The valve core 13 is used to cooperate with the high-pressure chamber 1201. The valve seat 15 is threadedly connected to the pressure rod 16. A positioning pin 17 perpendicular to the axis of the pressure relief chamber 1203 is provided on one side of the valve seat 15. A pin slot 18 is provided on the pump body 1 along the axis direction of the pressure relief chamber 1203 and cooperating with the positioning pin 17. The pressure rod 16 is connected to the pump body 1 so as to be able to rotate around its own axis.

[0052] The spring 14 can give the valve core 13 a force pointing to the high-pressure chamber 1201 to suppress the force of the diesel oil in the high-pressure chamber 1201 acting on the valve core 13 and pointing to the pressure relief chamber 1203, so that the valve core 13 can block the connection position between the high-pressure chamber 1201 and the pressure relief chamber 1203. When the pressure in the high-pressure chamber 1201 gradually increases, the force of the diesel oil in the high-pressure chamber 1201 acting on the valve core 13 and pointing to the pressure relief chamber 1203 also gradually increases, so that this force can overcome the force applied by the spring 14 and pointing to the high-pressure chamber 1201, and push the valve core 13 away from the connection position between the high-pressure chamber 1201 and the pressure relief chamber 1203, so that the high-pressure chamber 1201 and the pressure relief chamber 1203 are connected to each other, thereby realizing pressure relief.

[0053] Since a positioning pin 17 is provided on one side of the valve seat 15, under the cooperation of the positioning pin 17 and the pin slot 18, the valve seat 15 can only reciprocate along the axis direction of the pressure relief chamber 1203. Therefore, when the pressure lever 16 is rotated, under the meshing action of the pressure lever 16 and the valve seat 15, the valve seat 15 can reciprocate along the axis direction of the pressure relief chamber 1203, thereby compressing the spring 14 or reducing the compression of the spring 14, so as to adjust the magnitude of the force exerted by the spring 14 on the valve core 13 pointing to the high-pressure chamber 1201, and further realize the function of adjusting the pressure relief threshold of the pressure relief component.

[0054] As Figure 2 and Figure 4 shown, a rear cover 19 is detachably connected to the end of the suction chamber 101 away from the screw chamber 102. In this embodiment, the rear cover 19 is connected to the pump body 1 by bolts 23, which is convenient for the staff to perform maintenance. At the same time, in order to facilitate changing the pressure relief threshold of the pressure relief component through the pressure lever 16, a through hole matching the pressure lever 16 is provided on the rear cover 19. In order to prevent the oil in the pump body 1 from leaking from the gap between the pressure lever 16 and the rear cover 19, a sealing ring 20 is provided between the pressure lever 16 and the rear cover 19. Similarly, in order to prevent the oil in the pump body 1 from leaking from the gap between the pump body 1 and the rear cover 19, a gasket 21 is provided between the pump body 1 and the rear cover 19.

[0055] The implementation principle of a three-screw pump for marine low-sulfur diesel oil transportation in an embodiment of the present application is as follows: The motor is connected to the driving screw 2, the motor is started, the driving screw 2 is driven by the motor to rotate, and the driven screw 3 rotates together with the driving screw 2 under the meshing action, so that several dynamic sealing chambers are formed between the two ends of the spiral section of the driving screw 2 and the spiral section of the driven screw 3. These dynamic sealing chambers will continuously axially move the oil from the suction chamber 101 to the screw chamber 102, and gradually boost the pressure of the transported oil body until the connection section and the spiral section of the driving screw 2 and the driven screw 3, and finally discharge from the oil outlet channel 1041 located at the connection position of the connection section and the spiral section out of the screw chamber 102.

[0056] During the working process of the three-screw pump for marine low-sulfur diesel oil transportation, the pressure in the screw chamber 102 is also continuously increasing. Therefore, the pressure in the high-pressure chamber 1201 connected to the screw chamber 102 is also continuously increasing, and the force exerted by the diesel oil in the high-pressure chamber 1201 on the valve core 13 pointing to the pressure relief chamber 1203 is also gradually increasing, so that this force can overcome the force exerted by the spring 14 pointing to the high-pressure chamber 1201, push the valve core 13 away from the connection position between the high-pressure chamber 1201 and the pressure relief chamber 1203, and make the high-pressure chamber 1201 communicate with the pressure relief chamber 1203, thereby realizing pressure relief.

[0057] The above are all the preferred embodiments of the present application. The protection scope of the present application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A three-screw pump for transporting marine low-sulfur diesel, characterized in that: include: A pump body (1), the pump body (1) comprising a suction chamber (101) arranged along a first direction and a screw chamber (102) arranged at one end of the suction chamber (101) and connected to the suction chamber (101); an oil inlet (103) and an oil outlet (104) are arranged on one side of the pump body (1); the oil inlet (103) is connected to the suction chamber (101) via an oil inlet channel (1031) arranged along the first direction; the oil inlet channel (1031) is located on a side of the suction chamber (101) close to the screw chamber (102); the oil outlet (104) is connected to the screw chamber (102) via an oil outlet channel (1041) arranged obliquely; The screw portion comprises a driving screw (2) and two driven screws (3), wherein the driving screw (2) and the driven screw (3) both have a smooth connecting section and a spiral section with a thread, and the driving screw (2) and the driven screw (3) are both rotatably connected to the screw cavity (102) around their own axes, and the spiral section of the driven screw (3) is meshed with the spiral section of the driving screw (2).

2. The three-screw pump for transporting marine low-sulfur diesel according to claim 1, characterized in that: The screw chamber (102) comprises a main screw chamber (1021) arranged along the first direction and two auxiliary screw chambers (1022) arranged along the first direction, the auxiliary screw chambers (1022) being arranged on both sides of the main screw chamber (1021), the active screw (2) being arranged in the main screw chamber (1021), the driven screw (3) being arranged in the auxiliary screw chamber (1022), and the oil outlet channel (1041) being connected to the main screw chamber (1021).

3. The three-screw pump for transporting marine low-sulfur diesel according to claim 2, characterized in that: The connecting section of the active screw rod (2) is provided with a positioning flange (201), and the connecting section of the driven screw rod (3) is provided with a positioning groove (301) matching with the positioning flange (201).

4. The three-screw pump for transporting marine low-sulfur diesel according to claim 1, characterized in that: A pump front flange (4) is provided at one end of the screw cavity (102) away from the suction cavity (101); a connecting section of the active screw (2) passes through the pump front flange (4) and is rotatably connected to the pump front flange (4); a lubrication cavity (401) is provided on a side of the pump front flange (4) close to the pump body (1); an oil replenishment channel (402) connected to the lubrication cavity (401) is provided on the pump front flange (4); the lubrication cavity (401) is isolated from the screw cavity (102) by a first sealing component; a second sealing component is provided between the active screw (2) and the pump front flange (4).

5. The three-screw pump for transporting marine low-sulfur diesel according to claim 4, characterized in that: The first sealing assembly comprises a first oil deflector ring (5), a second oil deflector ring (6) and a ball bearing (7); the first oil deflector ring (5) and the ball bearing (7) are arranged on the active screw (2) in sequence along the first direction; the second oil deflector ring (6) is arranged on the driven screw (3), and the second oil deflector ring (6) is in contact with the first oil deflector ring (5).

6. The three-screw pump for transporting marine low-sulfur diesel according to claim 4, characterized in that: The second sealing assembly comprises a mechanical seal (9) and a skeleton seal (10), wherein the mechanical seal (9) and the skeleton seal (10) are sequentially arranged on the active screw (2) along the first direction.

7. The three-screw pump for transporting marine low-sulfur diesel according to claim 4, characterized in that: The number of the oil replenishment channel (402) is at least one, and a screw plug (22) is provided at one end of the oil replenishment channel (402) away from the lubrication cavity (401).

8. The three-screw pump for transporting marine low-sulfur diesel according to claim 1, characterized in that: The pump body (1) further comprises a pressure relief chamber (12), wherein the pressure relief chamber (12) comprises a high pressure chamber (1201) and a pressure relief chamber (1203) which are interconnected, wherein the high pressure chamber (1201) is connected to the screw chamber (102) via a pressure relief channel (1202), and the pressure relief chamber (1203) is connected to the suction chamber (101), and a pressure relief component for controlling the connection and disconnection between the high pressure chamber (1201) and the pressure relief chamber (1203) is provided in the pressure relief chamber (1203).

9. The three-screw pump for transporting marine low-sulfur diesel according to claim 8, characterized in that: The inner diameter of the high-pressure chamber (1201) is smaller than the inner diameter of the pressure relief chamber (1203). The pressure relief assembly includes a valve core (13), a spring (14), a valve seat (15) and a pressure rod (16). The valve core (13) is connected to the valve seat (15) through the spring (14). The valve core (13) is used to cooperate with the high-pressure chamber (1201). The valve seat (15) is threadedly connected to the pressure rod (16). A positioning pin (17) perpendicular to the axis of the pressure relief chamber (1203) is provided on one side of the valve seat (15). A pin groove (18) arranged along the axial direction of the pressure relief chamber (1203) and cooperating with the positioning pin (17) is provided on the pump body (1). The pressure rod (16) is connected to the pump body (1) so as to be rotatable around its own axis.

10. The three-screw pump for transporting marine low-sulfur diesel according to claim 9, characterized in that: One end of the suction chamber (101) away from the screw chamber (102) is detachably connected to a rear cover (19), the rear cover (19) is provided with a through hole matching the pressure rod (16), and a sealing ring (20) is provided between the pressure rod (16) and the rear cover (19).

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