External circulation water pump of small-displacement diesel engine

Abstract

The external circulation water pump of the small-displacement diesel engine comprises a water pump shell and a transmission shell installed on one side of the water pump shell, a water inlet and a water outlet are formed in the water pump shell, and the side, away from the transmission shell, of the water pump shell is detachably connected with an end cover used for sealing the water pump shell. A flexible impeller is installed in the water pump shell, a transmission shaft is installed in the transmission shell, and a water seal is arranged between the water pump shell and the transmission shell. The sealing performance between the transmission shell and the water pump shell can be improved through the water seal, in addition, even if the water seal loses efficacy, the transmission shell exists between the water pump shell and the diesel engine, seawater entering the transmission shell can be rapidly discharged through the through hole, and therefore the seawater cannot enter an engine gearbox, the influence on a diesel engine lubricating system is avoided, and the service life of the diesel engine is prolonged. Normal operation of the diesel engine is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water pumps, in particular to an external circulating water pump for a small displacement diesel engine. BACKGROUND

[0002] According to the requirements in 4.5.1.1 of the third part of the China Classification Society "Steel Sea-going Ship Classification Rules", for a small displacement diesel engine for ships, when one main engine is installed, one main cooling water pump with sufficient capacity at the maximum power output of the main engine should be provided, and according to the requirements in 9.4.2.2 of the third part of the "Steel Sea-going Ship Classification Rules", the water temperature of the diesel engine needs to be set to high temperature alarm, and the design can provide a flow of 10 m 3 / h and a lift of 6 meters for the small displacement diesel engine, effectively controlling the outlet water temperature of the small displacement diesel engine to 90℃, meeting the design and use requirements of the small displacement diesel engine.

[0003] In addition, with the development of technology, users have higher and higher requirements for the environment of the ship engine room, and the heat dissipation of the diesel engine as the largest heat source in the engine room will cause the temperature in the engine room to rise rapidly, which is not conducive to the power torque output of the diesel engine and the work of the maintenance personnel in the engine room.

[0004] At present, the patent with the publication number CN216406955U discloses an on-board cooling water pump for a marine diesel engine, which comprises an intermediate shaft, a cooling water pump body, a bearing shell and a gear box shell; the cooling water pump body, the bearing shell and the gear box shell are respectively provided with a cooling water pump impeller, a bearing and a driving gear connected with the intermediate shaft; the gear box shell is connected with the diesel engine, and the diesel engine is provided with a driving gear engaged with the driving gear. The cooling water pump is integrated on the diesel engine, the driving gear is engaged with the driving gear to drive the intermediate shaft, the bearing supports the intermediate shaft to drive the cooling water pump impeller, thereby realizing a high sea water lift, sea water heat exchange and effectively achieving the cooling and heat dissipation requirements of the diesel engine.

[0005] For the above-mentioned related technology, the inventors believe that the following defects exist: the water pump structure is complex, the casting cost is high, the water cavity part and the driving part are very close, once the water seal fails, sea water will leak into the driving part and mix with oil, thereby affecting the normal operation of the diesel engine, and therefore improvement is needed. CONTENT OF THE UTILITY MODEL

[0006] In view of the deficiencies of the prior art, the present application provides an external circulating water pump for a small displacement diesel engine, aiming to solve the above problems.

[0007] The application discloses an outer circulating water pump of a small-displacement diesel engine, which comprises a water pump shell and a transmission shell mounted on one side of the water pump shell, wherein the water pump shell is provided with an inlet and an outlet, the side of the water pump shell away from the transmission shell is detachably connected with an end cover for sealing the water pump shell, a flexible impeller is arranged in the water pump shell, a transmission shaft is arranged in the transmission shell, one end of the transmission shaft extends into the water pump shell and is connected with the impeller, the other end of the transmission shaft extends out of the transmission shell and is connected with a driving gear, a water seal is arranged between the water pump shell and the transmission shell, the water seal is sleeved on the transmission shaft, the water pump shell is provided with a clamping groove for clamping the water seal, a plurality of through holes are arranged on the circumferential outer side wall of the end of the transmission shell close to the water pump shell, and a fixing portion for fixing on the diesel engine is connected to the outer wall of the transmission shell.

[0008] By adopting the technical scheme, the water seal can improve the sealing performance between the transmission shell and the water pump shell, and even if the water seal fails, the transmission shell exists between the water pump shell and the diesel engine, seawater entering the transmission shell can be quickly discharged through the through holes, so that the seawater cannot enter the engine gear box, thereby avoiding affecting the lubrication system of the diesel engine and ensuring normal operation of the diesel engine.

[0009] Optionally, the transmission shaft is sleeved with a first rotary bearing and a second rotary bearing, and the inner side wall of the transmission shell is correspondingly provided with a first thrust groove for clamping the first rotary bearing and a second thrust groove for clamping the second rotary bearing.

[0010] Optionally, the first rotary bearing is a single-row deep groove ball bearing, and the second rotary bearing is a double-row deep groove ball bearing.

[0011] By adopting the technical scheme, the double-row deep groove ball bearing has higher radial and axial bearing capacity than the single-row deep groove ball bearing, can better bear larger load, and ensures the stability and reliability of the driving shaft under high load or unstable working conditions. Secondly, the double-row deep groove ball bearing can provide better axial positioning, reduce the axial movement of the shaft, thereby improving the operation stability of the entire pump system, reducing vibration and noise, and prolonging the service life of the pump. The single-row deep groove ball bearing is suitable for light to medium load applications and performs well at high speed, ensures high precision of the driving shaft, reduces friction and wear, and improves the operation efficiency of the pump. In addition, the deep groove ball bearing structure is simple and convenient to maintain, the single-row deep groove ball bearing is easy to replace and maintain, and the double-row deep groove ball bearing provides longer service life and reduces maintenance frequency. This combined design can adapt to various working conditions, whether light or heavy load, and can provide good support and protection to ensure stable operation of the pump under various conditions.

[0012] Optionally, the transmission shaft is a spline transmission shaft, and a copper sleeve is embedded in the middle of the impeller and sleeved on the spline shaft of the transmission shaft.

[0013] Optionally, the inner side wall of the water pump housing is provided with a filter grid at the water inlet.

[0014] By adopting the above technical scheme, the filter grid can block foreign matters from entering the water pump housing, and can reduce cavitation and reduce the impact damage of cavitation to the impeller.

[0015] Optionally, the drive gear is sleeved on one end of the transmission shaft, and a gear bolt for fixing the drive gear is threadedly connected on the transmission shaft.

[0016] Optionally, a sealing ring is sleeved on one end of the transmission housing close to the drive gear.

[0017] By adopting the above technical scheme, the sealing ring can improve the sealing performance between the transmission housing and the diesel engine.

[0018] Optionally, a sealing glue is arranged between the end cover and the water pump housing, and the end cover and the water pump housing are fixed by a plurality of mounting bolts.

[0019] By adopting the above technical scheme, the sealing glue can improve the sealing performance between the end cover and the water pump housing.

[0020] Optionally, the impeller is made of ethylene-propylene-diene rubber material.

[0021] By adopting the above technical scheme, firstly, the ethylene-propylene-diene rubber has excellent chemical corrosion resistance and can resist the corrosion of various acids, alkalis and other chemicals, is suitable for conveying liquid containing corrosive medium, and prolongs the service life of the impeller; secondly, the ethylene-propylene-diene rubber maintains good physical properties in a wide temperature range, and can work normally in high temperature or low temperature environment, and adapts to different working conditions; in addition, the ethylene-propylene-diene rubber has good wear resistance, can reduce the wear caused by solid particles in the liquid, improves the durability of the impeller, the ethylene-propylene-diene rubber also has good softness and elasticity, can absorb vibration and impact to a certain extent, reduces noise, improves the running stability of the pump, and the ethylene-propylene-diene rubber material is easy to process and form, can manufacture precise impeller shape, and meets various design requirements.

[0022] Optionally, the end cover and the water pump housing are both made of copper-zinc alloy.

[0023] By adopting the above technical scheme, the copper-zinc alloy has good corrosion resistance, especially in water environment, which helps to prolong the service life of the water pump. Secondly, the copper-zinc alloy has sufficient mechanical strength and hardness, can withstand pressure and wear, and ensures the stability and reliability of the water pump. In addition, the copper-zinc alloy has good processability, easy to cast, forge and machine, and is convenient to manufacture parts with complex shape. At the same time, its high thermal conductivity helps to improve the heat exchange efficiency, which is particularly beneficial to parts that need to dissipate heat. The copper-zinc alloy also has a good appearance, natural brightness, and does not need additional treatment to maintain its beauty.

[0024] In summary, the present application includes at least one of the following beneficial technical effects:

[0025] 1. The water seal can improve the sealing between the transmission housing and the water pump housing. In addition, even if the water seal fails, there is still a transmission housing between the water pump housing and the diesel engine. The seawater entering the transmission housing can be quickly discharged through the through hole, so the seawater cannot enter the engine gear box, thereby avoiding affecting the lubrication system of the diesel engine and ensuring the normal operation of the diesel engine.

[0026] 2. Compared with single-row deep groove ball bearings, double-row deep groove ball bearings have higher radial and axial load capacity, can better withstand larger loads, and ensure the stability and reliability of the drive shaft under high load or unstable working conditions. Secondly, double-row deep groove ball bearings can provide better axial positioning, reduce the axial movement of the shaft, thereby improving the running stability of the entire pump system, reducing vibration and noise, and prolonging the service life of the pump. Single-row deep groove ball bearings are suitable for light to medium load applications and perform well at high speed, ensuring high precision of the drive shaft, reducing friction and wear, and improving the operating efficiency of the pump. In addition, the deep groove ball bearing structure is simple and easy to maintain, and the single-row deep groove ball bearing is easy to replace and maintain, while the double-row deep groove ball bearing provides longer service life and reduces maintenance frequency. This combined design can adapt to various working conditions, whether light or heavy load, and can provide good support and protection to ensure stable operation of the pump under various conditions.

[0027] 3. The EPDM rubber has excellent chemical corrosion resistance and can resist the corrosion of various acids, alkalis and other chemicals, is suitable for conveying liquids containing corrosive media, and prolongs the service life of the impeller. Secondly, the EPDM rubber maintains good physical properties within a wide temperature range and can work normally in high temperature or low temperature environments, adapting to different working conditions. In addition, the EPDM rubber has good wear resistance, can reduce wear caused by solid particles in the liquid, improves the durability of the impeller, and has good softness and elasticity, which can absorb vibration and impact to a certain extent, reduce noise, improve the running stability of the pump, and the EPDM rubber material is easy to process and form, can be manufactured into precise impeller shape, and meets various design requirements.

[0028] 4、Copper-zinc alloy has good corrosion resistance, especially in water environment, which helps to extend the service life of the water pump, secondly, copper-zinc alloy has sufficient mechanical strength and hardness, which can withstand pressure and wear, ensuring the stability and reliability of the water pump, in addition, copper-zinc alloy has good processing performance, easy to cast, forge and machine, which is convenient for manufacturing complex shaped parts, at the same time, its high thermal conductivity helps to improve the heat exchange efficiency, which is particularly beneficial to the parts that need to dissipate heat, copper-zinc alloy also has good appearance, natural brightness, no additional treatment is needed to maintain the beauty. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic diagram of the embodiment of the present application.

[0030] Figure 2 is a cross-sectional schematic diagram of the embodiment of the present application.

[0031] Figure 3 is an explosion schematic diagram of the embodiment of the present application.

[0032] BRIEF DESCRIPTION OF DRAWINGS:

[0033] 1, end cover; 11, mounting bolt; 2, impeller; 3, water pump shell; 31, water inlet; 311, filter grid; 32, water outlet; 33, water seal; 4, transmission shaft; 41, first rotating bearing; 42, second rotating bearing; 5, transmission shell; 51, fixing bolt; 52, through hole; 6, drive gear; 61, gear bolt; 7, sealing ring. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element, or one or more intervening elements can be present therebetween. When an element is described as "connected" to another element, it can be directly connected to another element, or one or more intervening elements can be present therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in the specification are only for the purpose of illustration.

[0035] Unless otherwise defined, all technical and scientific terms used in the specification are the same as those commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" used in the specification includes any and all combinations of one or more related listed items.

[0036] The embodiment of the present application discloses a small displacement diesel engine external circulating water pump. Refer to Figure 1 and Figure 2 , including water pump housing 3 and the transmission housing 5 installed on one side of the water pump housing 3 by fixing bolt 51.

[0037] Refer to Figure 2 and Figure 3 , the water pump housing 3 is provided with water inlet 31 and water outlet 32, the side of the water pump housing 3 away from the transmission housing 5 is detachably connected with the end cover 1 for closing the water pump housing 3. The end cover 1 is made of copper-zinc alloy H59-GB / T5231, has good corrosion resistance, the inner surface outer edge of the end cover 1 is precisely milled with IT8 grade, and when the end face of the water pump housing 3 is sealed, the Loctite SI587 plane sealant is applied. The end cover 1 is fixed on the water pump housing 3 through six mounting bolts 11, the mounting bolts 11 are high-strength flange face bolts, and the tightening torque is 35 Nm. Considering that the cooling medium transported by the external circulating water pump in most cases is seawater, the seawater has high corrosiveness, therefore, the surface of the mounting bolt 11 is provided with zinc-aluminum coating rust prevention, and the Dacromet treatment can effectively inhibit seawater corrosion.

[0038] Refer to Figure 2 and Figure 3The flexible impeller 2 is installed in the water pump shell 3, the transmission shaft 4 is installed in the transmission shell 5, one end of the transmission shaft 4 extends into the water pump shell 3 and is connected with the impeller 2, the other end of the transmission shaft 4 extends out of the transmission shell 5 and is connected with the driving gear 6. The water seal 33 is arranged between the water pump shell 3 and the transmission shell 5, the water seal 33 is sleeved on the transmission shaft 4, the water pump shell 3 is provided with a clamping groove for clamping the water seal 33, and the outer end of the water seal 33 is provided with a dustproof felt. A plurality of through holes 52 are arranged on the circumferential outer side wall of the end of the transmission shell 5 close to the water pump shell 3, and the outer wall of the transmission shell 5 is fixedly connected with a fixing part for fixing on the diesel engine. The impeller 2 and the water seal 33 of the external circulating water pump are maintained or repaired and replaced through the end cover 1, the end cover 1 is located at the side of the external circulating water pump, the space is sufficient, and the end cover 1 is convenient to disassemble and assemble. The water seal 33 can improve the sealing performance between the transmission shell 5 and the water pump shell 3, in addition, even if the water seal 33 fails, there is still the transmission shell 5 between the water pump shell 3 and the diesel engine, and the seawater entering the transmission shell 5 can be quickly discharged through the through holes 52, so the seawater cannot enter the engine gear box, thereby avoiding affecting the lubrication system of the diesel engine and ensuring the normal operation of the diesel engine. The impeller 2 is a flexible impeller 2 made of ethylene propylene diene rubber. First, the ethylene propylene diene rubber has excellent chemical corrosion resistance and can resist the corrosion of various acids, alkalis and other chemicals, is suitable for conveying liquid containing corrosive medium, and prolongs the service life of the impeller 2; secondly, the ethylene propylene diene rubber maintains good physical properties within a wide temperature range, and can work normally in high-temperature or low-temperature environment, and adapts to different working conditions; in addition, the ethylene propylene diene rubber has good wear resistance, can reduce the wear caused by solid particles in the liquid, improves the durability of the impeller 2, the ethylene propylene diene rubber also has good softness and elasticity, can absorb vibration and impact to a certain extent, reduce noise, improve the running stability of the pump, and the ethylene propylene diene rubber material is easy to process and form, can manufacture precise impeller 2 shape, and meets various design requirements.

[0039] With reference to Figure 2 and Figure 3 The water pump shell 3 is made of copper-zinc alloy H59-GB / T 5231. The copper-zinc alloy has good corrosion resistance, especially in water environment, which helps to prolong the service life of the water pump, secondly, the copper-zinc alloy has sufficient mechanical strength and hardness, can withstand pressure and wear, ensures the stability and reliability of the water pump, in addition, the copper-zinc alloy has good processability, is easy to cast, forge and machine, is convenient for manufacturing complex-shaped parts, at the same time, its high thermal conductivity is helpful to improve the heat exchange efficiency, which is particularly beneficial to parts that need to dissipate heat.

[0040] With reference to Figure 2 and Figure 3, the inner cavity of the water pump shell 3 is intersected by two eccentric arcs with a radius difference of 5mm and an eccentric distance of 10mm. When the impeller 2 rotates to the eccentric piece of the inner cavity of the water pump shell 3, the impeller 2 is extruded and bent to form a vacuum, and the pressure difference between the inside and outside will suck the cooling medium into the water pump shell 3 through the water inlet 31. The impeller 2 rotates at high speed, and when the impeller 2 rotates to the eccentric piece again, it is extruded by the inner cavity of the water pump shell 3, and the cooling medium is smoothly discharged from the pump body through the water outlet 32. The high-speed rotation of the impeller 2 drives the cooling medium to enter the water inlet 31 and be sprayed out of the water outlet 32. Through test testing, the self-suction height of the water inlet 31 is 1.5m / 10s, when the small displacement diesel engine reaches 3000rpm, the outer circulating water pump impeller 2 rotates at the same speed, the pressure of the water inlet 31 reaches ≥60kPa, and the flow rate is ≥170L / min.

[0041] With reference to Figure 2 and Figure 3 , the inner side wall of the water pump shell 3 is fixedly connected with a filter grid 311 at the water inlet 31. The filter grid 311 can block foreign matter from entering the water pump shell 3, while reducing cavitation and reducing the impact damage of cavitation on the impeller 2.

[0042] With reference to Figure 2 and Figure 3 , the transmission shaft 4 is a spline transmission shaft, and the copper bushing embedded in the middle of the impeller 2 is bonded between the impeller 2 and the copper bushing by vulcanization. The copper bushing has a spline inner hole in the middle, and the copper bushing is fixedly sleeved on the spline shaft of the transmission shaft 4 through the spline inner hole.

[0043] With reference to Figure 2 and Figure 3The first rotating bearing 41 and the second rotating bearing 42 are sleeved on the transmission shaft 4, and the inner side wall of the transmission housing 5 is correspondingly provided with a first thrust groove for clamping the first rotating bearing 41 and a second thrust groove for clamping the second rotating bearing 42. The first thrust groove and the second thrust groove completely constrain the transmission shaft 4. The first rotating bearing 41 is a single-row deep groove ball bearing, and the second rotating bearing 42 is a double-row deep groove ball bearing. The double-row deep groove ball bearing has higher radial and axial bearing capacity than the single-row deep groove ball bearing, can better withstand larger loads, and ensures the stability and reliability of the drive shaft under high load or unstable working conditions. Secondly, the double-row deep groove ball bearing can provide better axial positioning, reduce the axial movement of the shaft, thereby improving the running stability of the entire pump system, reducing vibration and noise, and prolonging the service life of the pump. The single-row deep groove ball bearing is suitable for light to medium load applications and performs well at high speed, ensuring high precision of the drive shaft, reducing friction and wear, and improving the operating efficiency of the pump. In addition, the deep groove ball bearing structure is simple and easy to maintain, the single-row deep groove ball bearing is easy to replace and maintain, and the double-row deep groove ball bearing provides longer service life and reduces maintenance frequency. This combined design can adapt to various working conditions, whether it is light or heavy load, and can provide good support and protection to ensure stable operation of the pump under various conditions.

[0044] With reference to Figure 2 and Figure 3 , the drive gear 6 is sleeved on one end of the transmission shaft 4, and the transmission shaft 4 is threadedly connected with a gear bolt 61 for fixing the drive gear 6. The rotation direction of the water pump is consistent with the tightening direction of the gear bolt 61.

[0045] With reference to Figure 2 and Figure 3 , the transmission housing 5 is sleeved with a sealing ring 7 near one end of the drive gear 6, which can improve the sealing performance between the transmission housing 5 and the diesel engine.

[0046] The implementation principle of the outer circulating water pump of the small displacement diesel engine is as follows: when the small displacement diesel engine works, the gear chamber drives the outer circulating water pump driving gear 6 to rotate through the intermediate gear, the speed ratio is 1:1, the driving gear 6 drives the impeller 2 to rotate in the water pump shell 3 through the transmission shaft 4, the impeller 2 is pressed and bent to form a vacuum when rotating to the eccentric piece in the inner cavity of the water pump shell 3, the pressure difference between the inside and the outside sucks the cooling medium into the water pump shell 3 through the water inlet 31, the high-speed rotating outer circulating water pump, when the impeller 2 rotates to the eccentric piece again, it is pressed in the inner cavity of the water pump shell 3, the cooling medium is smoothly discharged from the pump body through the seawater outlet, the high-speed rotation of the impeller 2 drives the cooling medium from the water inlet 31 to the water outlet 32. The high-speed rotation of the impeller 2 forms the flow and lift of the outer circulating water pump; the water seal 33 and the sealing ring 7 ensure the sealing state of the water cavity and the lubricating system. The driving gear 6 is lubricated by the oil splashing in the gear chamber of the diesel engine, the first rotating bearing 41 and the second rotating bearing 42 are maintenance-free bearings, which have the characteristics of high performance and long service life. The impeller 2 and the water seal 33 are replaced by disassembling the end cover 1, the end cover 1 is located at the side of the water pump shell 3, which is convenient to disassemble and assemble and is convenient to maintain.

[0047] The application can be directly installed on the small displacement diesel engine, reducing the risk brought by user's self-installation and improving user experience; in addition, the gear transmission is adopted, which improves the transmission efficiency and avoids the damage of the diesel engine caused by the aging and fracture of the traditional seawater pump using the triangular belt; the application has simple structure and is convenient to install, adopts the special water seal 33 and oil seal arrangement, improves the sealing effect, and at the same time can avoid the influence on the lubricating system of the small displacement diesel engine when the water seal 33 fails.

[0048] The above are preferred embodiments of the application, which do not limit the protection scope of the application, therefore: any equivalent changes made on the structure, shape and principle of the application should be covered within the protection scope of the application.

Claims

1. A low volume diesel engine external circulating water pump characterized by: The utility model provides a water pump, including water pump casing (3) and the transmission casing (5) of installation in water pump casing (3) one side, the water inlet (31) and the water outlet (32) are seted up on water pump casing (3), the side of water pump casing (3) facing away from transmission casing (5) is detachably connected with the end cover (1) for closing water pump casing (3), the flexible impeller (2) is installed in water pump casing (3), the transmission shaft (4) is installed in transmission casing (5) inside, one end of transmission shaft (4) is inserted into water pump casing (3) and is connected with impeller (2), the other end is connected with drive gear (6) and is projected in transmission casing (5), the water seal (33) is arranged between water pump casing (3) and transmission casing (5), the water seal (33) is set on transmission shaft (4), the water pump casing (3) is set up with the clamping groove of water seal (33) carding, the circumferential lateral wall of the one end of transmission casing (5) close to water pump casing (3) is set apart with a plurality of through -hole (52), the outer wall of transmission casing (5) is connected with the fixed part for fixing on diesel engine.

2. A low volume diesel engine external water pump as claimed in claim 1, wherein: The first rotating bearing (41) and the second rotating bearing (42) are arranged on the transmission shaft (4), and the first thrust groove for the first rotating bearing (41) and the second thrust groove for the second rotating bearing (42) are arranged on the inner side wall of the transmission casing (5).

3. A low volume diesel engine external water pump as claimed in claim 2, wherein: The first rotating bearing (41) is a single-row deep groove ball bearing, and the second rotating bearing (42) is a double-row deep groove ball bearing.

4. A low volume diesel engine external water pump as claimed in claim 1, wherein: The transmission shaft (4) is a spline transmission shaft (4), the copper sleeve is embedded in the middle of the impeller (2), and the copper sleeve is arranged on the spline shaft of the transmission shaft (4).

5. A low volume, external circulation water pump for a diesel engine as defined in claim 1, characterized in that: The filter grid (311) is arranged on the inner side wall of the water pump casing (3) at the water inlet (31).

6. A low volume, external circulation water pump for a diesel engine as defined in claim 1, characterized in that: The drive gear (6) is arranged on one end of the transmission shaft (4), and the gear bolt (61) for fixing the drive gear (6) is threadedly connected to the transmission shaft (4).

7. A low volume, external circulation water pump for a diesel engine as defined in claim 1, characterized in that: The sealing ring (7) is arranged on one end of the transmission casing (5) close to the drive gear (6).

8. A low volume, external circulation water pump for a diesel engine as defined in claim 1, characterized in that: The sealing glue is arranged between the end cover (1) and the water pump casing (3), and the end cover (1) and the water pump casing (3) are fixed by the plurality of mounting bolts (11).

9. A low volume, external circulation water pump for a diesel engine as defined in claim 1, characterized in that: The impeller (2) is made of ethylene-propylene-diene rubber.

10. A low volume, external circulation water pump for a diesel engine as defined in claim 1, characterized in that: The end cover (1) and the water pump casing (3) are made of copper-zinc alloy.

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