A deep-water liquid-driven centrifugal pump and underwater power system

Abstract

This invention discloses a deep-water hydraulically driven centrifugal pump and underwater power system, relating to the field of deep-water centrifugal pump technology. It includes a centrifugal pump unit, a hydraulic motor unit, and a transition chamber. The two ends of the transition chamber are sealed and connected to the power output side of the hydraulic motor unit and the power input side of the centrifugal pump unit, respectively. The output shaft of the hydraulic motor unit and the drive shaft of the centrifugal pump unit extend into the transition chamber and are electrically connected within it. The transition chamber is filled with hydraulic oil to balance the pressure difference between the inside and outside of the transition chamber. By sealing the transition chamber between the hydraulic motor unit and the centrifugal pump unit and filling it with hydraulic oil, this invention effectively seals the power input side of the centrifugal pump unit and the power output side of the hydraulic motor unit. The hydraulic oil balances the pressure difference between the inside and outside of the transition chamber, thereby preventing seawater from entering the hydraulic motor unit and causing oil contamination, ensuring stable operation in deep-water environments.

Description

Technical Field

[0001] This invention relates to the field of deep-water centrifugal pump technology, and in particular to a deep-water liquid-driven centrifugal pump and underwater power system. Background Technology

[0002] Deep-sea suction anchor installations or drilling mud circulation without a riser require operation at depths of hundreds to thousands of meters to pump seawater or mud out of subsea equipment. Conventional electric submersible pumps (ESPs) are underwater lifting devices that are completely submerged to raise deep water to the surface or a certain height. Their applicable depth is generally no more than 70 meters, which cannot meet the demands of high-volume deep-sea applications. Conventional centrifugal pumps, on the other hand, use a motor or actuator to drive an impeller, causing the water to rotate at high speed. The water is then thrown towards the outer edge of the impeller by centrifugal force and flows out through the volute casing. Centrifugal pumps are characterized by large displacement and high head, but their actuators are usually dry motors, making them unsuitable for underwater applications. Therefore, conventional centrifugal pumps are unsuitable for underwater operations, while conventional ESPs have limited diving depths and cannot meet the requirements of deep-water conditions. Deep-sea suction anchor installation or drilling mud circulation without riser typically uses ROVs or subsea power stations to provide hydraulic power, but there is currently no mature liquid-driven centrifugal pump technology in China.

[0003] For example, Chinese patent CN2779710Y discloses a drive motor for a submersible centrifugal pump, including a rotatable, supported drive shaft, a stator surrounding a rotor, and a heat-dissipating motor housing. The motor housing consists of a front end wall with one side connectable to the centrifugal pump, an inner shell, and a cladding. The inner shell supports the stator and is made of a thermally conductive material, maintaining thermal contact with the front end wall. The cladding surrounds the inner shell at a certain radial spacing, forming a sealed annular space between the inner shell and the cladding. Electrical components for driving the motor are located within this annular space. This solution addresses the sealing problem of the underwater motor by employing a junction box sealing structure. The centrifugal pump is driven by the underwater motor, and the overall structure is vertical, suitable for shallow water operation, but with a limited displacement.

[0004] For example, Chinese patent CN201779093U discloses a deep-water suction-type cylindrical foundation installation pump skid. One end of the junction box is connected to the surface equipment via an umbilical cable, and the other end is connected to the underwater hydraulic pump station and the monitoring and control system via optical fiber. The monitoring and control system transmits and provides feedback signals to the surface equipment through the junction box and umbilical cable. The monitoring and control system inputs the feedback control signals into the hydraulic control valve box. The hydraulic control valve box is connected to the output end of the underwater hydraulic pump station, the hydraulic chuck cylinder, the hydraulically driven water pump, and a two-position three-way ball valve via pipelines. Seawater inlet and outlet are provided between one end of the two-position three-way ball valve; a flange for connecting the suction-type cylindrical foundation is provided between the other ends of the two-position three-way ball valve. This solution mentions a hydraulically driven water pump, but mainly describes the control principle of the pump skid system, without describing the specific structure of the hydraulically driven water pump. Summary of the Invention

[0005] The purpose of this invention is to provide a deep-water hydraulic centrifugal pump and underwater power system to solve the problems existing in the prior art. By sealing a transition chamber between the hydraulic motor unit and the centrifugal pump unit, and filling the transition chamber with hydraulic oil, the transition chamber can effectively seal the power input side of the centrifugal pump unit and the power output side of the hydraulic motor unit. The hydraulic oil balances the pressure difference between the inside and outside of the transition chamber, thereby preventing seawater from entering the hydraulic motor unit and causing oil contamination, and ensuring stable operation in deep-water environments.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a deep-water hydraulically driven centrifugal pump, comprising a centrifugal pump unit, a hydraulic motor unit, and a transition chamber. The two ends of the transition chamber are respectively sealed and connected to the power output side of the hydraulic motor unit and the power input side of the centrifugal pump unit. The output shaft of the hydraulic motor unit and the drive shaft of the centrifugal pump unit are respectively inserted into the transition chamber and are poweredly connected within the transition chamber. The transition chamber is filled with hydraulic oil for balancing the pressure difference between the inside and outside of the transition chamber.

[0008] Preferably, the drain port of the hydraulic motor unit is connected to the transition chamber through a drain pipe, and a one-way valve for maintaining the hydraulic pressure in the transition chamber is also provided on the shell wall of the transition chamber.

[0009] Preferably, the centrifugal pump unit includes a first housing and a first cover, the first cover being connected to the first housing and located on the power input side of the centrifugal pump unit; the hydraulic motor unit includes a second housing and a second cover, the second cover being connected to the second housing and located on the power output side of the hydraulic motor unit; the transition chamber includes a third housing and a bearing located on the inner diameter side of the third housing; the first cover, the third housing, and the second cover are sequentially connected; the drive shaft passes through the first cover and is mounted on the inner ring of the bearing; the output shaft passes through the second cover and is connected to the drive shaft via a spline connection.

[0010] Preferably, the first cover body has a radially protruding central portion forming a first sleeve fitted onto the outer diameter side of the drive shaft, and a mechanical seal is provided between the first sleeve and the drive shaft.

[0011] Preferably, the mechanical seal includes a sealing seat, a stationary ring, and a rotating ring arranged sequentially toward the hydraulic motor unit. The rotating ring is pressed against the stationary ring by a compression spring. A first sealing ring is provided between the first sleeve and the sealing seat, a second sealing ring is provided between the sealing seat and the stationary ring, and a third sealing ring is provided between the rotating ring and the drive shaft.

[0012] Preferably, the edge of the first cover protrudes radially to form a second sleeve, the end of the third housing is provided with an annular flange, the end of the second sleeve is sealed to the annular flange, an annular receiving cavity is formed between the first sleeve and the second sleeve, and the annular receiving cavity communicates with the inner cavity of the transition chamber.

[0013] Preferably, a bearing assembly is provided on the inner diameter side of the third housing. The bearing assembly includes a first bearing disposed on the side near the first cover and a second bearing disposed on the side near the second cover. A bearing end cap is provided on the outer side of the first bearing, and the outer side of the second bearing is pressed by the second cover.

[0014] Preferably, a high-speed oil seal is provided between the output shaft and the second housing. The high-speed oil seal has a U-shaped cross-section, with the opening of the U-shaped structure facing the inside of the second housing, and the two arms of the U-shaped structure respectively fitting the inner diameter sides of the output shaft and the sealing cover.

[0015] The present invention also provides an underwater propulsion system, including the deep-water hydraulic centrifugal pump, hydraulic pump and oil tank described above. The oil inlet of the hydraulic motor unit is connected to the oil tank in sequence through the oil delivery pipe, the hydraulic pump and the oil suction pipe. The oil return port of the hydraulic motor unit is connected to the oil tank through the oil return pipe. The outlet of the one-way valve is connected to the oil tank through the oil discharge pipe.

[0016] Preferably, a piston is provided inside the oil tank, which divides the oil tank into an oil storage chamber and a water storage chamber. The piston is connected to a spring that applies a thrust to the oil storage chamber. The oil storage chamber is connected to the oil inlet and oil return port of the hydraulic motor unit and the outlet of the one-way valve. The water storage chamber is provided with water inlet and outlet.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] (1) The present invention provides a sealed transition chamber between the hydraulic motor unit and the centrifugal pump unit. The transition chamber is filled with hydraulic oil. The transition chamber can effectively seal the side of the centrifugal pump unit that receives power and the side of the hydraulic motor unit that outputs power. The hydraulic oil balances the pressure difference between the inside and outside of the transition chamber, thereby preventing seawater from entering the hydraulic motor unit and causing oil contamination, and ensuring stable operation in deep water environment.

[0019] (2) In this invention, the drain port of the hydraulic motor unit is connected to the transition chamber through the drain pipe, which makes the pressure on both sides of the high-speed oil seal of the hydraulic motor unit equal. This can prevent the hydraulic oil in the hydraulic motor unit from overflowing and prevent seawater (especially in deep water) from entering the hydraulic motor unit. This can effectively prevent external seawater from entering the hydraulic motor unit through the high-speed oil seal and contaminating the hydraulic oil in the hydraulic motor unit. Therefore, the existing high-speed oil seal structure of the hydraulic motor can still be used. With minor modifications, the connection between the centrifugal pump unit and the hydraulic motor unit can be achieved, and a good sealing effect can be achieved.

[0020] (3) By setting a one-way valve on the shell wall of the transition chamber, the present invention can maintain the pressure of the transition chamber higher than the external environment pressure. On this basis, by utilizing the pressure of the transition chamber and the squeezing action of the compression spring in the mechanical seal, it can be ensured that the pressure in the transition chamber is always higher than the pressure in the centrifugal pump unit chamber. The dynamic ring and static ring in the mechanical seal are always in close contact, forming an effective seal between hydraulic oil and seawater, preventing hydraulic oil from entering the centrifugal pump unit and causing hydraulic oil leakage. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the underwater propulsion system of the present invention;

[0023] Figure 2 This is a schematic diagram of the deep-water liquid-driven centrifugal pump structure of the present invention;

[0024] Figure 3 for Figure 2 Enlarged view of M;

[0025] Figure 4 for Figure 2 Enlarged view of N in the middle:

[0026] The components include: 1. Centrifugal pump unit; 11. First housing; 12. Impeller; 13. Mechanical seal; 131. Sealing seat; 132. First sealing ring; 133. Second sealing ring; 134. Stationary ring; 135. Dynamic ring; 136. Third sealing ring; 137. Compression spring; 14. Drive shaft; 15. First cover; 151. First sleeve; 2. Hydraulic pump; 3. Oil tank; 4. Suction pipe; 5. Delivery pipe; 6. Return pipe; 7. Drain pipe; 8. Discharge pipe; 9. Hydraulic motor unit; 91. Second housing; 92. Output shaft; 93. High-speed oil seal; 94. Second cover; 95. Sealing cover; 96. Fourth sealing ring; 10. Transition chamber; 101. Bearing end cover; 102. Third housing; 103. Check valve; 104. First bearing; 105. Second bearing. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The purpose of this invention is to provide a deep-water hydraulically driven centrifugal pump and underwater power system to solve the problems existing in the prior art. By sealing a transition chamber between the hydraulic motor unit and the centrifugal pump unit, and filling the transition chamber with hydraulic oil, the transition chamber can effectively seal the power input side of the centrifugal pump unit and the power output side of the hydraulic motor unit. The hydraulic oil balances the pressure difference between the inside and outside of the transition chamber, thereby preventing seawater from entering the hydraulic motor unit and causing oil contamination, and ensuring stable operation in deep-water environments.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figures 1-4As shown, this invention provides a deep-water hydraulically driven centrifugal pump, comprising a centrifugal pump unit 1, a hydraulic motor unit 9, and a transition chamber 10. The centrifugal pump unit 1 has a structure largely consistent with a conventional centrifugal pump, including a first housing 11 and an impeller 12 disposed within the first housing 11. Water enters through the suction port due to the self-priming force generated by the impeller 12, and flows out through the discharge port using centrifugal force. The impeller 12 is connected to a drive shaft 14, which drives the impeller 12 to rotate. The hydraulic motor unit 9 has a structure largely consistent with a conventional hydraulic motor, including a second housing 91 and a hydraulically driven rotating component disposed within the second housing 91. The rotating component is connected to an output shaft 92. The transition chamber 10 can be cylindrical or other shaped, with opposing end openings. The two end openings are respectively sealed and connected to the power output side of the hydraulic motor unit 9 and the power input side of the centrifugal pump unit 1, forming a sealed chamber. For sealing, a flange structure with a sealing ring can be used for compression connection, or the flange of an end cap can be used for connection. The output shaft 92 of the hydraulic motor unit 9 and the drive shaft 14 of the centrifugal pump unit 1 are respectively inserted into the transition chamber 10 and are poweredly connected within the transition chamber 10 (using a spline or coupling structure, etc.). The transition chamber 10 is filled with hydraulic oil to balance the pressure difference between the inside and outside of the transition chamber 10. The transition chamber 10 can be connected to an oil inlet for hydraulic oil replenishment, or it can be a closed chamber to seal the hydraulic oil within. By sealing the transition chamber 10 between the hydraulic motor unit 9 and the centrifugal pump unit 1, and filling the transition chamber 10 with hydraulic oil, the present invention can effectively seal the power input side of the centrifugal pump unit 1 and the power output side of the hydraulic motor unit 9 using the transition chamber 10. By using the hydraulic oil to balance the pressure difference between the inside and outside of the transition chamber 10, the present invention can prevent seawater from entering the hydraulic motor unit 9 and causing oil contamination, thus ensuring stable operation in deep-water environments.

[0031] The drain port (DR port) of the hydraulic motor unit 9 is connected to the transition chamber 10 through the drain pipe 7, which ensures that the pressure on both sides of the high-speed oil seal 93 of the hydraulic motor unit 9 is equal. This prevents hydraulic oil from overflowing from the hydraulic motor unit 9 and also prevents seawater (especially in deep water environments) from entering the hydraulic motor unit 9. This effectively avoids external seawater entering the hydraulic motor unit 9 through the high-speed oil seal 93 and contaminating the hydraulic oil inside the hydraulic motor unit 9. Therefore, the existing high-speed oil seal 93 structure of the hydraulic motor can still be used, achieving the connection between the centrifugal pump unit 1 and the hydraulic motor unit 9 with minor modifications and achieving a good sealing effect. A one-way valve 103 is also provided on the shell wall of the transition chamber 10 to maintain the hydraulic pressure inside the transition chamber 10. The drain pressure of the one-way valve 103 can be adjusted to obtain the required appropriate pressure, maintaining the pressure in the transition chamber 10 higher than the external ambient pressure.

[0032] Furthermore, the centrifugal pump unit 1 may include a first housing 11 and a first cover 15. The first cover 15 is detachably connected to the first housing 11 to facilitate the installation of internal components of the first housing 11. The first cover 15 is located on the power input side of the centrifugal pump unit 1 and is used to connect with the transition chamber 10. The hydraulic motor unit 9 includes a second housing 91 and a second cover 94. The second cover 94 is detachably connected to the second housing 91 and is located on the power output side of the hydraulic motor unit 9. It may be in the form of a flange, with one side connected to the second housing 91 by threads and the other side connected to the transition chamber 10. The transition chamber 10 includes a third housing 102 and one or more bearings located on the inner diameter side of the third housing 102. The outer ring of the bearing is connected to the inner diameter side of the third housing 102 and is used to connect with the drive shaft 14. The first cover 15, the third housing 102, and the second cover 94 are connected sequentially. The drive shaft 14 passes through the first cover 15 and is installed in the inner ring of the bearing. The output shaft 92 passes through the second cover 94 and is connected to the drive shaft 14 via a spline connection. At this time, the transition chamber 10 serves as a bearing chamber, which can balance the internal and external pressure difference, maintain the seal of the centrifugal pump unit 1 and the hydraulic motor unit 9, and also form a seal and lubrication for the bearing.

[0033] like Figure 2 As shown, a first sleeve 151 is formed by a radially protruding portion of the first cover 15, which is fitted onto the outer diameter side of the drive shaft 14. A mechanical seal 13 is provided between the first sleeve 151 and the drive shaft 14. The mechanical seal 13 can achieve a seal where the drive shaft 14 passes through the first cover 15. The mechanical seal 13 can adopt an existing structure, in which a moving ring 135 and a stationary ring 134 are sequentially arranged toward the hydraulic motor unit 9, and the pressure inside the centrifugal pump unit 1 and the pressure of the spring push the moving ring 135 to press against the stationary ring 134 to achieve a seal.

[0034] like Figure 3 As shown, the mechanical seal 13 has an improved structure compared to the existing structure, including a sealing seat 131, a stationary ring 134, and a rotating ring 135 arranged sequentially towards the hydraulic motor unit 9. The rotating ring 135 is pressed against the stationary ring 134 by a compression spring 137. A first sealing ring 132 is provided between the first sleeve 151 and the sealing seat 131, a second sealing ring 133 is provided between the sealing seat 131 and the stationary ring 134, and a third sealing ring 136 is provided between the rotating ring 135 and the drive shaft 14. With the above-described mechanical seal 13, the pressure in the transition chamber 10 and the compression action of the compression spring 137 in the mechanical seal 13 can be combined to apply pressure to the rotating ring 135, ensuring that the pressure in the transition chamber 10 is always higher than the pressure in the centrifugal pump unit 1. The rotating ring 135 and the stationary ring 134 in the mechanical seal 13 are always in close contact, forming an effective barrier between hydraulic oil and seawater, preventing hydraulic oil from entering the centrifugal pump unit 1 and causing hydraulic oil leakage.

[0035] The one-way valve 103 maintains the pressure inside the transition chamber 10 and the hydraulic motor unit 9 higher than the external ambient pressure. The pressure difference can be set as needed and is defined as ΔP. ​​The stationary ring 134 and the rotating ring 135 are pressed together by the clamping spring 137, which generates a static seal of about 1 bar. At this time, the pressure acting on the rotating ring 135 and the stationary ring 134 is ΔP + 1 bar. Therefore, as long as the head of the centrifugal pump unit 1 does not exceed ΔP + 1 bar, that is, the pressure difference before the centrifugal pump unit 1 starts is (ΔP + 1 bar), and after starting it is (ΔP + 1 bar - head pressure > 0), the effective isolation between the hydraulic oil and seawater on both sides of the mechanical seal 13 can be maintained. Usually, the centrifugal pump unit 1 has a large displacement and a small head. Therefore, setting a smaller ΔP can maintain the pressure inside the transition chamber 10 higher than the internal pressure of the centrifugal pump unit 1, maintaining effective isolation. Furthermore, the smaller the ΔP, the lower the oil discharge pressure on the hydraulic motor unit 9, and the less impact it has on the hydraulic motor unit 9, which is beneficial for protecting the hydraulic motor unit 9.

[0036] The first cover 15 protrudes radially from its edge to form a second sleeve. An annular flange is provided at the end of the third housing 102, and the end of the second sleeve is sealed to the annular flange. An annular cavity is formed between the first sleeve 151 and the second sleeve, which can accommodate the bearing end cover 101 installed at the end of the third housing 102. The annular cavity communicates with the inner cavity of the transition chamber 10, meaning that hydraulic oil can simultaneously fill both the annular cavity and the transition chamber 10. This ensures that hydraulic oil can be distributed between the first sleeve 151 and the drive shaft 14, guaranteeing an effective seal between the drive shaft 14 and the centrifugal pump unit 1.

[0037] A bearing assembly is provided on the inner diameter side of the third housing 102. The bearing assembly includes a first bearing 104 located near the first cover 15 and a second bearing 105 located near the second cover 94. A bearing end cap 101 is provided on the outer side of the first bearing 104 (relative to the outer side of the transition chamber 10, i.e., the side near the centrifugal pump unit 1). The outer side of the second bearing 105 (relative to the outer side of the transition chamber 10, i.e., the side near the hydraulic motor unit 9) is pressed against the second cover 94. A shoulder is also provided at a corresponding position on the drive shaft 14 to limit the axial position of the first bearing 104 and the second bearing 105.

[0038] like Figure 4As shown, a high-speed oil seal 93 is provided between the output shaft 92 and the second housing 91. The high-speed oil seal 93 is annularly sleeved on the output shaft 92, with its inner diameter side in dynamic contact with the output shaft 92 and its outer diameter side having a sealing cover 95. A fourth sealing ring 96 is provided between the sealing cover 95 and the second housing 91 for sealing connection. The high-speed oil seal 93 has a U-shaped cross-section, with the opening of the U-shaped structure facing inwards towards the second housing 91, and the two arms of the U-shaped structure respectively fitting against the inner diameter sides of the output shaft 92 and the sealing cover 95. The hydraulic oil in the hydraulic motor unit 9 enters the opening of the U-shaped structure (i.e., the annular cavity surrounded by the two arms of the U-shaped structure), and the pressure of the hydraulic oil will squeeze the two arms in opposite directions, thereby ensuring the sealing effect of the high-speed oil seal 93. If the transition chamber 10 is not provided, due to the high external pressure of the deep-sea environment, the pressure of the hydraulic motor unit 9 may be lower than the external environmental pressure before it starts, causing seawater to enter the hydraulic motor unit 9 through the high-speed oil seal 93 and contaminate the hydraulic oil. By setting up the transition chamber 10 and connecting the hydraulic motor unit 9 and the transition chamber 10 through the drain pipe 7, the pressure of the hydraulic motor unit 9 and the transition chamber 10 can be made equal, that is, the pressure difference inside and outside the high-speed oil seal 93 is equal and higher than or equal to the external ambient pressure, thereby avoiding the occurrence of the above-mentioned problems.

[0039] like Figure 1 and Figure 2 As shown, the present invention also provides an underwater propulsion system, which may include the deep-water hydraulic centrifugal pump, hydraulic pump 2, and oil tank 3 described above. The oil inlet (P port) of the hydraulic motor unit 9 is connected to the oil tank 3 sequentially through the oil delivery pipe 5, the hydraulic pump 2, and the oil suction pipe 4. The hydraulic pump 2 can be driven by an underwater motor and can rely on an ROV or an underwater power station to provide hydraulic power. The deep-water hydraulic centrifugal pump uses the hydraulic motor unit 9 to drive the centrifugal pump unit 1 and can rely on an ROV or an underwater power station to provide hydraulic power, eliminating the need for an expensive underwater motor to drive the centrifugal pump unit 1, resulting in a compact structure and low cost. The oil return port (T port) of the hydraulic motor unit 9 is connected to the oil tank 3 through the oil return pipe 6. The outlet of the one-way valve 103 is connected to the oil tank 3 through the oil drain pipe 8.

[0040] A piston is installed inside the oil tank 3, dividing it into an oil storage chamber and a water storage chamber. The piston is connected to a spring that applies thrust to the oil storage chamber. The oil storage chamber is connected to the oil inlet and return port of the hydraulic motor unit 9, as well as the outlet of the one-way valve 103. The water storage chamber is equipped with inlet and outlet water ports. With the above structure, the oil tank 3 can be a pressure-compensated structure, which can automatically balance the pressure inside the oil tank 3 with the external environmental pressure, ensuring that the oil tank 3 can adapt to deep-water conditions.

[0041] The underwater propulsion system of this invention operates as follows:

[0042] Hydraulic pump 2 draws oil from oil tank 3 through suction pipe 4 and delivers the hydraulic oil to the inlet P port of hydraulic motor unit 9 through oil delivery pipe 5. Hydraulic oil returning from the return port T port of hydraulic motor unit 9 flows back to oil tank 3 through return pipe 6. Oil tank 3 is equipped with a piston and spring to automatically balance the pressure inside the tank with the external environmental pressure. After hydraulic pump 2 starts, it hydraulically drives the output shaft 92 of hydraulic motor unit 9 to rotate. The rotation of output shaft 92 drives the drive shaft 14 of centrifugal pump unit 1 to rotate, which in turn drives the impeller 12 to rotate. Seawater is pumped from the suction port of centrifugal pump unit 1 and discharged from the discharge port.

[0043] The drain port DR of the hydraulic motor unit 9 is connected to the A port of the transition chamber 10 through the drain pipe 7. The B port of the transition chamber 10 is connected to the check valve 103. The check valve 103 is connected to the oil tank 3 through the drain pipe 8. That is, the oil drained from the hydraulic motor unit 9 enters the transition chamber 10 through the A port, flows out of the transition chamber 10 through the B port and the check valve 103, and flows back to the oil tank 3 after entering the drain pipe 8. The transition chamber 10 is filled with hydraulic oil. The internal pressure of the hydraulic motor unit 9 is equal to the internal pressure of the transition chamber 10. External seawater will not contaminate the hydraulic oil through the high-speed oil seal 93.

[0044] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A deep water liquid driven centrifugal pump characterized by: The centrifugal pump unit, the hydraulic motor unit and the transition chamber are provided, two ends of the transition chamber are respectively sealed and connected on one side of the power output of the hydraulic motor unit and one side of the power input of the centrifugal pump unit, the output shaft of the hydraulic motor unit and the driving shaft of the centrifugal pump unit respectively extend into the transition chamber and are power connected in the transition chamber, and the transition chamber is filled with hydraulic oil for balancing the pressure difference between the inside and outside of the transition chamber. The oil discharge port of the hydraulic motor unit is communicated with the transition chamber through an oil discharge pipe, and a one-way valve for maintaining the oil pressure in the transition chamber is further arranged on the shell wall of the transition chamber. The centrifugal pump unit comprises a first shell and a first cover body, the first cover body is connected to the first shell and located on one side of the power input of the centrifugal pump unit, the hydraulic motor unit comprises a second shell and a second cover body, the second cover body is connected to the second shell and located on one side of the power output of the hydraulic motor unit, the transition chamber comprises a third shell and a bearing located on the inner diameter side of the third shell, the first cover body, the third shell and the second cover body are sequentially connected, the driving shaft penetrates through the first cover body and is installed on the inner ring of the bearing, and the output shaft penetrates through the second cover body and is connected with the driving shaft through a spline fit. The middle part of the first cover body protrudes radially to form a first sleeve which is sleeved on the outer diameter side of the driving shaft, and a mechanical seal is arranged between the first sleeve and the driving shaft. The mechanical seal comprises a sealing seat, a static ring and a dynamic ring which are sequentially arranged towards the hydraulic motor unit, the dynamic ring is pressed on the static ring through a compression spring, a first sealing ring is arranged between the first sleeve and the sealing seat, a second sealing ring is arranged between the sealing seat and the static ring, and a third sealing ring is arranged between the dynamic ring and the driving shaft.

2. The deep water liquid-driven centrifugal pump of claim 1, wherein: The edge of the first cover body protrudes radially to form a second sleeve, the end of the second sleeve is sealingly connected with an annular flange arranged on the end of the third shell, an annular accommodating cavity is formed between the first sleeve and the second sleeve, and the annular accommodating cavity is communicated with the inner cavity of the transition chamber.

3. The deep well liquid ring centrifugal pump of claim 1, wherein: A bearing set is arranged on the inner diameter side of the third shell, the bearing set comprises a first bearing arranged on one side close to the first cover body and a second bearing arranged on one side close to the second cover body, a bearing end cover is arranged on the outer side of the first bearing, and the outer side of the second bearing is compressed through the second cover body.

4. The deep water liquid-driven centrifugal pump of claim 1, wherein: A high-speed oil seal is arranged between the output shaft and the second shell, the cross section of the high-speed oil seal is in a U-shaped structure, the opening of the U-shaped structure faces the inside of the second shell, and the two arms of the U-shaped structure respectively abut the inner diameter sides of the output shaft and a sealing cover body.

5. An underwater power system characterized by: The deep water liquid-driven centrifugal pump, the hydraulic pump and the oil tank are provided, the oil inlet of the hydraulic motor unit is sequentially communicated with the oil tank through an oil supply pipe, the hydraulic pump and an oil suction pipe, the oil return port of the hydraulic motor unit is communicated with the oil tank through an oil return pipe, and the outlet of the one-way valve is communicated with the oil tank through an oil discharge pipe.

6. The underwater power system of claim 5, wherein: The oil tank is provided with a piston, the piston divides the oil tank into an oil storage cavity and a water storage cavity, the piston is connected with a spring which applies a pushing force to the oil storage cavity side, the oil storage cavity is communicated with an oil inlet, an oil return port of the hydraulic motor unit and an outlet of the one-way valve, and the water storage cavity is provided with an inlet and outlet water port.

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