US-12618398-B2 - Active pressure compensator for deep-sea sampling and pressure compensation method thereof

US12618398B2US 12618398 B2US12618398 B2US 12618398B2US-12618398-B2

Abstract

An active pressure compensator for deep-sea sampling includes a spring chamber, a cam piston pump, and a circuit chamber; the spring chamber is configured to provide compensation liquid for the cam piston pump; the cam piston pump is configured to be able to draw liquid from the spring chamber and pump liquid to the circuit chamber; the circuit chamber is configured to be connected to a mechanism to be pressurized, and is provided therein with a pressure sensor and a control circuit board, the pressure sensor is configured to detect pressures of the compensation liquid from cam piston pump and the mechanism to be pressurized, the control circuit board is configured to control working of the cam piston pump based on pressure data feedback from the pressure sensor and thereby realize active pressure compensation for the mechanism to be pressurized. A pressure compensation method using the compensator is further provided.

Inventors

Shijun Wu
Zhiheng Chen
YIQIANG DAI
Canjun YANG

Assignees

ZHEJIANG UNIVERSITY

Dates

Publication Date: 20260505
Application Date: 20240308
Priority Date: 20230511

Claims (17)

1 . An active pressure compensator for deep-sea sampling, comprising a spring chamber, a cam piston pump connected to the spring chamber, and a circuit chamber connected to the cam piston pump, wherein: the spring chamber is configured to provide liquid with a pressure higher than an environmental pressure by at least 0.5 MPa for the cam piston pump; the cam piston pump is configured to be capable of inhaling the liquid from the spring chamber and pumping out the liquid to the circuit chamber; the circuit chamber is configured to be connected to a mechanism to be pressurized and is provided therein with a pressure sensor and a control circuit board connected in communication with the pressure sensor, the pressure sensor is configured to detect pressures of liquid output by the cam piston pump and of the mechanism to be pressurized, the control circuit board is configured to send a control instruction to control working of the cam piston pump based on pressure data feedback from the pressure sensor and thereby realize active pressure compensation for the mechanism to be pressurized.
2 . The active pressure compensator for deep-sea sampling according to claim 1 , wherein the cam piston pump comprises a liquid chamber, and a liquid inlet valve and a liquid outlet valve in communication with the liquid chamber; the liquid inlet valve and the liquid outlet valve are respectively connected to the spring chamber and the circuit chamber; the cam piston pump further comprises a piston that is movable along an axial direction of the cam piston pump, a stop rotating block connected to the piston, a roller assembly connected to the stop rotating block, a cam in linkage with the roller assembly, and a drive motor configured to drive the cam to rotate; wherein when the drive motor drives the cam to rotate, the cam applies an axial pushing force to the roller assembly, such that the roller assembly, through the stop rotating block, pushes the piston to move axially in a direction toward the liquid chamber, such that liquid in the liquid chamber is pumped out through the liquid outlet valve.
3 . The active pressure compensator for deep-sea sampling according to claim 2 , wherein both the liquid inlet valve and the liquid outlet valve are one-way valves.
4 . The active pressure compensator for deep-sea sampling according to claim 2 , wherein the piston is sheathed with a first a first elastic member, the first elastic member is configured to store elastic potential energy when the piston is pushed by the stop rotating block to move, and further configured to release elastic potential energy when the pushing force of the stop rotating block to the piston disappears, such that the piston, the stop rotating block, and the cam return to original positions; wherein when the piston, the stop rotating block, and the cam return to original positions, the cam piston pump inhales liquid into the liquid chamber through the liquid inlet valve.
5 . The active pressure compensator for deep-sea sampling according to claim 4 , wherein the cam piston pump comprises a piston chamber, an intermediate chamber connected to the piston chamber, a motor chamber connected to the intermediate chamber, and a motor cover connected to the motor chamber; wherein the liquid chamber, the liquid inlet valve, and the liquid outlet valve are provided in the piston chamber, the piston, the stop rotating block, the roller assembly, the cam, and the drive motor are provided in a hollow cavity running through the intermediate chamber and the motor chamber, and between the piston and the piston chamber there is provided a sealing member, which is configured to seal the liquid chamber.
6 . The active pressure compensator for deep-sea sampling according to claim 5 , wherein among the piston chamber, the intermediate chamber, the motor chamber, and the motor cover, bolts or screws are used for connection.
7 . The active pressure compensator for deep-sea sampling according to claim 5 , wherein the cam piston pump further comprises a motor coupling configured to fix the drive motor in the motor chamber.
8 . The active pressure compensator for deep-sea sampling according to claim 5 , wherein the cam piston pump further comprises silicon carbide balls provided between the stop rotating block and the piston chamber, the silicon carbide balls are configured to perform circumferential restriction for the stop rotating block to prevent the stop rotating block from rotating; the stop rotating block has a front end, a middle end, and a rear end connected sequentially, the cam piston pump further comprises a piston coupling configured to fixedly connect the piston to the front end of the stop rotating block and a retaining ring, and the cam piston pump further comprises a roller shaft provided at the rear end of the stop rotating block, the roller assembly is rotatably provided on the roller shaft.
9 . The active pressure compensator for deep-sea sampling according to claim 8 , wherein the cam has a linkage end and a drive end extending from the linkage end, the linkage end and the drive end are respectively connected to the rolling assembly and a rotation shaft of the drive motor, and between an outer side of the drive end and an inner side wall of the intermediate chamber there is further provided a bearing assembly.
10 . The active pressure compensator for deep-sea sampling according to claim 5 , wherein the motor cover is provided with a first interface configured to be connected with an oil bag, a second interface configured to be connected with the circuit chamber, and a third interface configured to be connected with the motor chamber, wherein the first interface is in communication with the third interface.
11 . The active pressure compensator for deep-sea sampling according to claim 2 , wherein the spring chamber comprises a water supplement interface and a spring chamber end cover that are respectively provided at two ends thereof, a valve poppet configured to control the water supplement interface to open and close, a water supplement chamber in communication with the water supplement interface, a water supplement chamber piston provided at a side of the water supplement chamber that is away from the valve poppet, a second elastic member having one end supported against the water supplement chamber piston and another end supported against the spring chamber end cover, and an accommodation chamber configured to mount the second elastic member.
12 . The active pressure compensator for deep-sea sampling according to claim 11 , wherein the water supplement chamber piston is provided thereon with two guide rings and a sealing ring provided between the two guide rings.
13 . The active pressure compensator for deep-sea sampling according to claim 11 , wherein the circuit chamber comprises a casing, a circuit cavity formed in the casing, and an interface part and a pressure compensation part that are respectively provided at two ends of the casing; wherein the interface part is provided with a first connection interface configured to be connected with a watertight connector to perform debugging and communication for the control circuit board in the circuit cavity, and a second connection interface configured to be connected to the cam piston pump; the pressure compensation part comprises a pressure compensation inlet connected to the liquid outlet valve of the cam piston pump, a mounting cavity configured to mount the pressure sensor, a sensor plug configured to fix the pressure sensor in the mounting cavity, a copper post connected to the sensor plug and located in the circuit cavity, and a pressure compensation outlet in communication with the pressure compensation inlet and the mounting cavity; the control circuit board is mounted on the copper post, the circuit cavity is further provided therein with a battery, and the circuit chamber is configured to be connected to the mechanism to be pressurized through the pressure compensation outlet.
14 . The active pressure compensator for deep-sea sampling according to claim 1 , wherein the mechanism to be pressurized is a sampling tube.
15 . The active pressure compensator for deep-sea sampling according to claim 1 , wherein the active pressure compensator further comprises an oil bag connected to the cam piston pump; the active pressure compensator further comprises a mounting frame configured to mount the cam piston pump, the spring chamber, the circuit chamber, and the oil bag, the mounting frame is a double-layer structure, wherein the cam piston pump and the circuit chamber are mounted on a first layer of the mounting frame, the spring chamber and the oil bag are provided at a second layer of the mounting frame, a position of the spring chamber is in correspondence with that of the cam piston pump, and a position of the oil bag is in correspondence with that of the circuit chamber.
16 . A pressure compensation method using the active pressure compensator for deep-sea sampling according to claim 1 , comprising the steps of: the pressure sensor in the circuit chamber detecting pressures of liquid output by the cam piston pump and of a mechanism to be pressurized; the control circuit board of the circuit chamber receiving pressure data detected by the pressure sensor, and when the pressure is lower than a preset pressure, sending a control instruction to the cam piston pump; the cam piston pump receiving the control instruction and pumping liquid in the cam piston pump to the circuit chamber to pressurize the mechanism to be pressurized.
17 . The pressure compensation method according to claim 16 , further comprising the steps of: connecting a water supplement interface of the spring chamber to a water supplement pump, and filling water into a water supplement chamber of the spring chamber by the water supplement pump; removing the water supplement pump, and connecting the water supplement interface to the cam piston pump; a pressure of a second elastic member of the spring chamber applying on a piston and thus transferring the pressure to the water in the water supplement chamber; opening a valve poppet and providing the water with a pressure higher than an environmental pressure by at least 0.5 MPa for the cam piston pump.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application claims priority of Chinese patent application No. CN202310527036.4 filed on May 11, 2023. The entire content of the above-identified application is incorporated herein by reference. TECHNICAL FIELD The present invention relates to the technical field of deep-sea sampling and pressure maintenance, in particular to an active pressure compensator for deep-sea sampling and a pressure compensation method thereof. BACKGROUND The sea area with a depth exceeding 1000 m is defined as the deep sea, which accounts for 88% of the total ocean coverage area and 75% of the total ocean volume, and contains abundant mineral, biological, oil and gas, and genetic resources. As a type of deep-sea exploration technology, sampling detection technology brings back valuable samples in the ocean, such as minerals, microorganisms, water quality, etc., and provides important assistance for exploring marine resources and promoting research of biology, ecology, etc. Pressure is an unneglectable influence factor when obtaining seabed samples. Pressure plays an important role in ensuring stability of samples and activity and integrity of microbial proteins. Moreover, pressure is also extremely important for maintaining not volatilizing dissolved gases and unchanged physical and chemical properties of hydrates in samples. For scenarios that require laboratory analysis of samples, it is not only necessary to ensure stable pressures of samples during sampling processes, but also necessary to ensure stable pressures during transfer processes after sample collection. Therefore, ensuring stability of sample pressures during sampling processes and researching pressure retention techniques are of great significance for sample fidelity and scientific research. The seawater pressure increases with the depth, reaching a maximum of over 110 MPa, which is located in the Mariana Trench at a depth of 10909 meters. In a process of sample recovery, the external seawater pressure continuously decreases. If measures are not taken to maintain a stable pressure, effectiveness of samples will be greatly reduced. Therefore, the research on deep-sea sampling pressure retention technology is of great significance. In the field of water sampling, existing research work can be divided into non-pressure holding sampling, passive pressure holding sampling, and active pressure holding sampling in terms of whether pressure compensation is applied to samples. Non-pressure holding sampling refers to a sampling method that tolerates pressure loss during a recovery process without any pressure compensation after sample collection is completed. Non-pressure holding sampling is commonly used in fields such as that are insensitive to sample pressure, in shallow water sampling, and so on. Processes of sampling and recovery of non-pressure holding sampling inevitably result in pressure loss and is unable to maintain in-situ pressure. Passive pressure holding sampling is also usually known as accumulator sampling, this type of sampling scheme generally involves pre-charging pressure gas into an accumulator in advance. When the external environmental pressure decreases, the pre-charging gas in the accumulator is released to achieve pressure compensation for samples. Although passive pressure holding sampling is relatively convenient, it has characteristics such as dangerous operation and inaccurate pressure holding. Active pressure holding sampling achieves active pressure holding for pressures of samples through an external pressure compensation device, and detects pressures of collected samples in real time for pressure compensation. Active pressure holding sampling can actively adjust pressures of samples to ensure stable pressures of samples, but to some extent, it increases structural complexity. For example, Chinese patent application with public No. CN114459818A discloses an active liquid precision compensation device and method for deep-sea pressure maintaining samplers, which uses three sets of motors, reduction boxes, and screw nuts to respectively drive three piston boosting cylinders with different areas to pressurize a sampling cylinder, its structure is very complex. In addition, this scheme need rely on an environmental pressure and pushing forces from the motors to the screws to pressurize the piston booster cylinder; if the environmental pressure is low but a high pressure is still required to be output, requirements for the motors, reducers, and screw nuts are very high. For another example, Chinese patent application with the public No. CN113251148A discloses an active pressure compensation device and a deep-sea pressure holding sampling system, which uses an electric motor, gear transmission, and screw transmission to push a piston to pressurize compensation liquid. However, the pressurized compensation liquid only plays a role of preventing axial displacement of a sealing ring from causing press