OIL-GAS SEPARATED PRESSURE CYLINDER

Abstract

An oil-gas separated pressure cylinder, which combines a hydraulic cylinder, a pneumatic cylinder and a pres-pressure cylinder, and keeps the applied compressed gas and the storage hydraulic fluid apart, maintaining the quality of the hydraulic fluid and saving the hydraulic fluid replacement cost. When the applied compressed gas enters the pre-pressure cylinder to move a pre-pressure cylinder piston in forcing the storage hydraulic fluid out of an oil storage space of the pre-pressure cylinder into an oil storage space in the hydraulic cylinder, a hydraulic cylinder piston of the hydraulic cylinder is then forced by the hydraulic fluid to move a hydraulic cylinder piston rod against the workpiece, and then a pneumatic cylinder piston rod of the pneumatic cylinder is forced into the oil storage space of the hydraulic cylinder to enhance the pressure at the hydraulic cylinder piston rod against the workpiece.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pressure cylinder and more particularly, to an oil-gas separated pressure cylinder.

2. Description of the Related Art

Referring to FIG. 1, a conventional pressure cylinder 10 generally comprises a hydraulic cylinder 12, an air cylinder 14 vertically connected to the hydraulic cylinder 12, and a pre-pressure cylinder 16 laterally connected to the hydraulic cylinder 12. As illustrated in FIG. 2, when a compressed gas from an external pressure source enters an oil storage chamber 162 of the pre-pressure cylinder 16, the hydraulic fluid in the oil storage chamber 162 of the pre-pressure cylinder 16 will be forced through an oil passageway 18 into an oil storage chamber 122 of the hydraulic cylinder 12 to convert the received gas pressure to a pre-pressure against a piston 124 of the hydraulic cylinder 12. At this time, the piston rod 126 of the hydraulic cylinder 12 will be moved gradually toward the workpiece. Thereafter, the piston rod 142 of the air cylinder 14 will be forced by the air pressure generated by the air cylinder 14 to enter the oil storage chamber 122 of the hydraulic cylinder 12, enhancing the pressure at the piston rod 126 of the hydraulic cylinder 12 against the workpiece.

However, during the operation of the aforesaid prior art pressure cylinder 10, the hydraulic fluid in the pre-pressure cylinder 16 is inevitably kept in contact with the inputted compressed gas. If the inputted compressed gas contains a high percentage of water, the hydraulic fluid may be emulsified. Quality deterioration of the hydraulic fluid will affect the performance and lifespan of the internal components of the pressure cylinder. To avoid this problem, the operator must regularly replace the hydraulic fluid. However, regularly replacing the hydraulic fluid greatly increases the material cost. Further, after the working stroke of the pressure cylinder 10, the return pressure of the hydraulic fluid of the pre-pressure cylinder 16 forces the inputted compressed gas toward the outside. However, the fluid mixture of the hydraulic fluid and the compressed gas may be volatized into the outside open air during compressed gas discharging process, causing air pollution and bringing harm to the health of the operator. Further, in order to facilitate movement of the hydraulic fluid by the pressure of the inputted compressed air, the pressure cylinder 10 can simply be set in vertical, limiting its application.

Therefore, there is a room for improvement on the conventional pressure cylinder.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide an oil-gas separated pressure cylinder, which has less limitation in installation, maintains the quality of the hydraulic fluid, saves the hydraulic fluid replacement cost, and reduces air pollution.

To achieve this and other objects of the present invention, an oil-gas separated pressure cylinder comprises a hydraulic cylinder, a pneumatic cylinder, and a pre-pressure cylinder. The hydraulic cylinder comprises a first oil storage space, a hydraulic cylinder piston set in the first oil storage space and a hydraulic cylinder piston rod connected to the hydraulic cylinder piston. The pneumatic cylinder is connected to one end of the hydraulic cylinder, comprising a pneumatic cylinder piston and a pneumatic cylinder piston rod. The pneumatic cylinder piston rod has one end thereof connected to and movable by the pneumatic piston, and an opposite end thereof inserted into the first oil storage space of the hydraulic cylinder The pre-pressure cylinder is connected to one side of the hydraulic cylinder, comprising a second oil storage space in communication with the first oil storage space, a gas passage in communication with the second oil storage space and a pre-pressure cylinder piston set in the second oil storage space within an output end of the gas passage and movable by an applied compressed gas.

Based on the aforesaid design, the air-gas separated pressure cylinder can be set in any desired direction. Further, the gas passage for compressed gas is isolated from the second oil storage space for hydraulic fluid by the pre-pressure cylinder piston of the pre-pressure cylinder, avoiding contact between the compressed gas and the hydraulic fluid. Thus, the quality of the hydraulic fluid is maintained, reducing the number of hydraulic fluid replacement times, saving the hydraulic fluid replacement cost and avoiding production of hydraulic fluid-gas mixture that may pollute the air.

Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a pressure cylinder according to the prior art.

FIG. 2 is a sectional view of an oil-gas separated pressure cylinder in accordance with the present invention.

FIG. 3 illustrates an operation flow of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 2, an air-gas separated pressure cylinder 20 in accordance with the present invention is shown. The air-gas separated pressure cylinder 20 comprises a hydraulic cylinder 30, an air cylinder 40, and a pre-pressure cylinder 50.

The hydraulic cylinder 30 comprises a hydraulic cylinder body 31, a hydraulic cylinder piston 32, a hydraulic cylinder piston rod 33, a seal member 34, and a spacer 35. The hydraulic cylinder piston 32 is set in the hydraulic cylinder body 31 and movable by the pressure of a hydraulic fluid. The hydraulic cylinder piston rod 33 has its top end connected with the hydraulic cylinder piston 32 and its bottom end facing toward the workpiece 60, and is movable by the hydraulic cylinder piston 32 to force its bottom end against the workpiece 60. The seal member 34 is mounted at the top end of the hydraulic cylinder body 31, defining with the hydraulic cylinder piston 32 a first oil storage space 36 for storing a hydraulic fluid 70. The spacer 35 is set between the seal member 34 and the hydraulic cylinder piston 32 to divide the first oil storage space 36 into an oil storage chamber 362 and a pressure chamber 364, wherein the volume of the pressure chamber 364 varies with the position of the hydraulic cylinder piston 32. Further, the hydraulic cylinder body 31 defines a radially extending first oil guide passage 37 in communication with the oil storage chamber 362 of the first oil storage space 36.

The air cylinder 40 comprises a pneumatic cylinder body 41, a pneumatic cylinder piston 42, and a pneumatic cylinder piston rod 43. The pneumatic cylinder body 41 has its bottom end connected to the top end of the hydraulic cylinder body 31 of the hydraulic cylinder 30. The pneumatic cylinder piston 42 is set in the pneumatic cylinder body 41 and movable by a compressed gas. The pneumatic cylinder piston rod 43 has its top end connected to the pneumatic cylinder piston 42 and its bottom end inserted through the seal member 34 into the inside of the oil storage chamber 362 of the hydraulic cylinder 30, and is movable by the hydraulic cylinder piston 42 to force its bottom end into the pressure chamber 364 of the hydraulic cylinder 30, as shown in FIG. 3, thereby enhancing the pressure.

The pre-pressure cylinder 50 comprises a pre-pressure cylinder body 51, a pre-pressure cylinder piston 52, and an oil filing tube 53. The pre-pressure cylinder body 51 is connected to one side of the hydraulic cylinder 30, comprising a second oil storage space 54 and a radially extending oil guide passage 55 in communication with the second oil storage space 54 and the first oil guide passage 34 of the hydraulic cylinder 30. The pre-pressure cylinder body 51 further comprises a gas passage 56 in communication with the second oil storage space 54 for access of an external compressed gas. The pre-pressure cylinder piston 52 is set in the second oil storage space 54 within the output end of the gas passage 56, and movable toward the bottom side by the pressure of the applied compressed gas. The oil filing tube 53 has its bottom end connected to the pre-pressure cylinder piston 52, and its top end extending out of the pre-pressure cylinder 50 and terminating in an oil filling hole 532 for allowing the operator to fill a new supply of hydraulic fluid 70 into the second oil storage space 54 as well as for exhausting air.

After understanding of the structural details of the oil-gas separated pressure cylinder 20, the operation and features of the oil-gas separated pressure cylinder 20 are outlined hereinafter.

Referring to FIG. 3 and FIG. 2 again, a compressed gas is guided from an external pressure source through the gas passage 56 of the pre-pressure cylinder 50 into the second oil storage space 54 to force the pre-pressure cylinder piston 52 of the pre-pressure cylinder 50 through the second oil guide passage 55 and the first oil guide passage 37 in forcing the hydraulic fluid 70 from the second oil storage space 54 into the first oil storage space 36 of the hydraulic cylinder 30. At this time, the hydraulic fluid 70 gives a pre-pressure to the hydraulic cylinder piston 32 of the hydraulic cylinder 30, forcing the hydraulic cylinder piston 32 of the hydraulic cylinder 30 to move the hydraulic cylinder piston rod 33 toward the workpiece 60. When the hydraulic cylinder piston rod 33 is approaching the workpiece 60, the pneumatic cylinder piston rod 43 of the pneumatic cylinder 40 is forced by the gas pressure of the pneumatic cylinder 40 to enter the pressure chamber 364 of the hydraulic cylinder 30, enhancing the pressure at the hydraulic cylinder piston rod 33 against the workpiece 60. After working at the workpiece 60, the hydraulic cylinder 30, the pneumatic cylinder 40 and the pre-pressure cylinder 50 are returned to their respective former positions for a next processing cycle.

Based on the aforesaid design, the air-gas separated pressure cylinder 20 can be set in vertical, horizontal or any other direction without affecting the operation of the pre-pressure cylinder piston 52 in moving the hydraulic fluid 70. Thus, the invention facilitates the installation of the air-gas separated pressure cylinder 20. Further, the gas passage 56 for compressed gas is isolated from the second oil storage space 54 for hydraulic fluid 70 by the pre-pressure cylinder piston 52 of the pre-pressure cylinder 50, avoiding contact between the compressed gas and the hydraulic fluid 70 either in the pre-pressure stroke, pressure stroke or return stroke Thus, the quality of the hydraulic fluid 70 is maintained, reducing the number of hydraulic fluid replacement times, saving the hydraulic fluid replacement cost and avoiding production of hydraulic fluid-gas mixture that may pollute the air.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Claims

1. An oil-gas separated pressure cylinder, comprising: a hydraulic cylinder comprising a first oil storage space, a hydraulic cylinder piston set in said first oil storage space and a hydraulic cylinder piston rod connected to said hydraulic cylinder piston;a pneumatic cylinder connected to one end of said hydraulic cylinder, said pneumatic cylinder comprising a pneumatic cylinder piston and a pneumatic cylinder piston rod, said pneumatic cylinder piston rod having one end thereof connected to and movable by said pneumatic piston and an opposite end thereof inserted into said first oil storage space of said hydraulic cylinder; anda pre-pressure cylinder connected to one side of said hydraulic cylinder, said pre-pressure cylinder comprising a second oil storage space in communication with said first oil storage space, a gas passage in communication with said second oil storage space and a pre-pressure cylinder piston set in said second oil storage space within an output end of said gas passage.

2. The oil-gas separated pressure cylinder as claimed in claim 1, wherein said hydraulic cylinder further comprises a seal member and a spacer, said seal member defining with said hydraulic cylinder piston said first oil storage space, said spacer being set between said seal member and said hydraulic cylinder piston to divide said first oil storage space into an oil storage chamber and a pressure chamber, said oil storage chamber being in communication with said second oil storage space of said pre-pressure cylinder, said pressure chamber having a volume variable with the position of said pneumatic cylinder piston; said pneumatic cylinder piston rod of said pneumatic cylinder is inserted through said seal member into said oil storage chamber and forcible by said pneumatic cylinder piston into said pressure chamber.

3. The oil-gas separated pressure cylinder as claimed in claim 1, wherein said hydraulic cylinder further comprises a first oil guide passage in communication with said first oil storage space; said pre-pressure cylinder further comprises a second oil guide passage in communication with said second oil storage space and said first oil guide passage.

4. The oil-gas separated pressure cylinder as claimed in claim 1, wherein said pre-pressure cylinder further comprises an oil filling tube, said oil filling tube having one end thereof connected to said pre-pressure cylinder piston and an opposite end thereof extending out of said pre-pressure cylinder and terminating in an oil filling hole.

5. The oil-gas separated pressure cylinder as claimed in claim 2, wherein said hydraulic cylinder further comprises a first oil guide passage in communication with said first oil storage space; said pre-pressure cylinder further comprises a second oil guide passage in communication with said second oil storage space and said first oil guide passage.