A hydraulic connection fastening device for the crosshead of a BOG compressor

Abstract

The present invention relates to the technical field of compressor equipment, and particularly relates to a hydraulic connection fastening device for the crosshead of a BOG compressor, which includes a thrust ring, a positioning ring, a pressure body, a locking nut, and a follower ring. The crosshead is located at one end of the piston rod, and the thrust ring, the positioning ring, and the pressure body are sequentially arranged on the piston rod and are coaxial. An oil cavity is provided inside the pressure body. A pressure piston and a sealing ring are arranged inside the oil cavity. The locking nut is sleeved on the pressure body and is in threaded cooperation with the pressure body, and the locking nut is spherically hinged to the follower ring. After the oil cavity of the hydraulic connection fastening device for the crosshead of a BOG compressor of the present invention is depressurized, the required connection pre-tightening force is achieved between the piston rod and the crosshead. And if the locking nut has a tendency of axial displacement, the locking nut will cause the follower ring to rotate relative to the locking nut, balance the force on the locking nut, prevent the locking nut from generating axial displacement, and further prevent the piston rod from bending, ensuring the normal use of the piston rod.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor equipment, and particularly relates to a hydraulic connection fastening device for a crosshead of a BOG compressor. Background Art

[0002] A BOG compressor is a device specifically used to process boil-off gas (BOG) generated in a liquefied natural gas (LNG) storage tank. Most BOG compressors adopt oil-free lubricated reciprocating compressors, and their working principle is the same as that of ordinary reciprocating compressors. The difference is that the inlet of the BOG compressor sucks in low-temperature gas. Therefore, the structures such as the first-stage cylinder block and piston of the compressor must be resistant to low temperature and prevent icing to ensure the normal use of the BOG compressor.

[0003] As an important component connecting the piston rod and the connecting rod, during the operation of the compressor, the crosshead bears complex forces such as alternating loads and inertial forces generated by the reciprocating motion of the piston. The connection between the crosshead and the piston rod of traditional BOG compressors mostly adopts a threaded connection method. During the installation process, a tool is used manually to tighten the nut to tightly connect the crosshead and the piston rod. However, this connection method is not firm enough and is extremely likely to cause the piston rod to break.

[0004] Chinese Patent CN2758526Y discloses a hydraulic connection fastening device for a crosshead, which includes a thrust ring, a spiral ring, an adjusting ring, a pressure body, a locking nut, a high-pressure joint of an oil pump, a sealing ring, and a pressure piston. During installation, after connecting the piston rod and the crosshead through the hydraulic connection fastening device, high-pressure oil is used to force the tail of the piston rod to generate elastic tensile deformation, and then the locking nut is screwed onto the end of the crosshead to achieve mechanical positioning. Then, the high-pressure oil is depressurized. After the high-pressure oil is depressurized, the piston rod will slowly recover. The pre-tightening force generated by the elastic deformation of the piston rod acts on the connecting thread between the pressure body and the locking nut, preventing the relative rotation of the pressure body and the locking nut, so as to achieve the required connection pre-tightening force between the piston rod and the crosshead, and complete the fastening connection between the piston rod and the crosshead.

[0005] However, due to the errors between parts, when the high-pressure oil is depressurized and the piston rod recovers and applies force to the connecting thread between the pressure body and the locking nut, the locking nut may produce an axial offset, and through the pressure body, apply a force other than the axial direction of the piston rod to the piston rod in the reverse direction, resulting in the axial offset of the piston rod and even causing the piston rod to bend, affecting the normal use of the piston rod and shortening the service life of the piston rod. Summary of the Invention

[0006] The present invention provides a hydraulic connection fastening device for the crosshead of a BOG compressor to solve the problem that when the existing hydraulic connection fastening device for the crosshead connects the piston rod and the crosshead, due to errors between parts, the locking nut may drive the piston rod to generate an axial offset, affecting the normal use of the piston rod.

[0007] The hydraulic connection fastening device for the crosshead of a BOG compressor of the present invention adopts the following technical solution: A hydraulic connection fastening device for the crosshead of a BOG compressor, used to connect the crosshead and the piston rod, includes a thrust ring, a positioning ring, a pressure body, a locking nut and a follower ring; the crosshead is located at one end of the piston rod, and the thrust ring, the positioning ring and the pressure body are arranged in sequence and coaxially on the piston rod along the first direction, and the first direction is the axial direction of the piston rod; the thrust ring is located on the side of the pressure body close to the crosshead in the first direction, the thrust ring abuts against the crosshead, the positioning ring is in threaded cooperation with the crosshead and abuts against the thrust ring, an adjusting ring is sleeved on the positioning ring, and the adjusting ring is in threaded cooperation with the positioning ring; an oil cavity is provided in the pressure body, and a pressure piston and a sealing ring are arranged in sequence in the oil cavity along the first direction, the pressure piston is located on the side of the sealing ring close to the positioning ring in the first direction, and the pressure piston abuts against the positioning ring; an oil pump connector is provided on the pressure body, and the oil pump connector is communicated with the oil cavity; the follower ring and the locking nut are arranged in sequence and coaxially in the first direction, the follower ring is located on the side of the locking nut close to the crosshead in the first direction and can abut against the crosshead, the locking nut is sleeved on the pressure body and is in threaded cooperation with the pressure body, and the locking nut is spherically hinged with the follower ring.

[0008] Further, a limiting plate is coaxially and fixedly arranged on the follower ring, the limiting plate is an arc-shaped plate, in the radial direction of the piston rod, the limiting plate is located between the locking nut and the pressure body, and the limiting plate is in threaded cooperation with the pressure body.

[0009] Further, a chute is opened on the inner peripheral wall surface of the locking nut, the limiting plate is installed in the chute, and the threads on the limiting plate can be connected with the threads on the inner peripheral wall surface of the locking nut.

[0010] Further, the piston rod includes a first rod body and a second rod body, the first rod body and the second rod body are arranged in sequence and fixedly connected in the first direction, the first rod body is an elastic rod, and the diameter of the first rod body is smaller than the diameter of the second rod body. The thrust ring, the positioning ring and the pressure body are all installed on the first rod body. A shoulder is provided at one end of the second rod body close to the first rod body in the first direction, and the pressure body abuts against the shoulder.

[0011] Further, three positioning bosses are arranged at intervals along the first direction on the first rod body.

[0012] Further, the thrust ring includes two ring bodies, both ring bodies are semi-circular structures, and the two ring bodies are installed on the piston rod through a first elastic member.

[0013] Further, the first elastic member is an annular spring.

[0014] Further, a manual ultra-high pressure oil pump is further included, and the manual ultra-high pressure oil pump is connected to the oil pump joint through a hose.

[0015] Further, an oil passage is provided on the pressure body, and the oil pump joint is communicated with the oil cavity through the oil passage.

[0016] Further, the adjusting ring and the positioning ring are connected by screws.

[0017] The beneficial effects of the present invention are as follows: A crosshead hydraulic connection fastening device of a BOG compressor of the present invention is provided with a thrust ring, a positioning ring, a pressure body, a locking nut and a follower ring in cooperation. After the oil cavity is depressurized, the pre-tightening force generated by the deformation of the piston rod will act on the connecting thread between the pressure body and the locking nut, preventing the relative rotation of the pressure body and the locking nut, so that the required connection pre-tightening force is achieved between the piston rod and the crosshead. And if the locking nut has a tendency of axial offset, the locking nut will cause the follower ring to rotate relative to the locking nut, balancing the force on the locking nut, preventing the locking nut from generating axial offset, and further preventing the piston rod from bending, ensuring the normal use of the piston rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the overall structure of an embodiment of a crosshead hydraulic connection fastening device of a BOG compressor of the present invention;

[0020] Figure 2 It is a front view of the overall structure of an embodiment of a crosshead hydraulic connection fastening device of a BOG compressor of the present invention;

[0021] Figure 3 For Figure 2 the sectional view along A-A in

[0022] Figure 4 For Figure 3 the enlarged view at B in

[0023] Figure 5 For Figure 4 the enlarged view at C in

[0024] Figure 6Schematic diagram of a follower ring of an embodiment of a crosshead hydraulic connection fastening device for a BOG compressor according to the present invention;

[0025] Figure 7 Schematic diagram of a lock nut of an embodiment of a crosshead hydraulic connection fastening device for a BOG compressor according to the present invention;

[0026] Figure 8 Schematic diagram of a piston rod of an embodiment of a crosshead hydraulic connection fastening device for a BOG compressor according to the present invention.

[0027] In the figure: 100, crosshead; 200, piston rod; 210, first rod body; 220, second rod body; 230, positioning boss; 300, thrust ring; 310, first elastic member; 400, positioning ring; 500, pressure body; 510, oil cavity; 520, pressure piston; 530, sealing ring; 540, oil pump joint; 600, lock nut; 610, chute; 700, follower ring; 710, limiting plate; 800, adjusting ring. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] An embodiment of a crosshead hydraulic connection fastening device for a BOG compressor according to the present invention is as Figures 1 to 8 shown.

[0030] A crosshead hydraulic connection fastening device for a BOG compressor, used to connect a crosshead 100 and a piston rod 200, includes a thrust ring 300, a positioning ring 400, a pressure body 500, a locking nut 600 and a follower ring 700. The crosshead 100 is located at one end of the piston rod 200. The thrust ring 300, the positioning ring 400 and the pressure body 500 are sequentially arranged on the piston rod 200 along a first direction and are coaxial. The first direction is the axial direction of the piston rod 200. The thrust ring 300 is located on the side of the pressure body 500 closer to the crosshead 100 in the first direction. The thrust ring 300 abuts against the crosshead 100. The positioning ring 400 is in threaded cooperation with the crosshead 100 and abuts against the thrust ring 300. An adjusting ring 800 is sleeved on the positioning ring 400, and the adjusting ring 800 is in threaded cooperation with the positioning ring 400. An oil cavity 510 is provided in the pressure body 500. A pressure piston 520 and a sealing ring 530 are sequentially arranged in the oil cavity 510 along the first direction. The pressure piston 520 is located on the side of the sealing ring 530 closer to the positioning ring 400 in the first direction, and the pressure piston 520 abuts against the positioning ring 400. An oil pump joint 540 is provided on the pressure body 500, and the oil pump joint 540 is communicated with the oil cavity 510.

[0031] The follower ring 700 and the locking nut 600 are sequentially arranged along the first direction and are coaxial. The follower ring 700 is located on the side of the locking nut 600 closer to the crosshead 100 in the first direction and can abut against the crosshead 100. The locking nut 600 is sleeved on the pressure body 500 and is in threaded cooperation with the pressure body 500. The locking nut 600 is ball-jointed with the follower ring 700.

[0032] Specifically, the adjusting ring 800 and the positioning ring 400 are connected by screws.

[0033] In this embodiment, by arranging the cooperation of the thrust ring 300, the positioning ring 400, the pressure body 500, the locking nut 600 and the follower ring 700, when connecting the piston rod 200 and the crosshead 100, first install the sealing ring 530 and the pressure piston 520 in the oil cavity 510 of the pressure body 500, and screw the locking nut 600 and the follower ring 700 into the pressure body 500. Then install the pressure body 500 on the piston rod 200.

[0034] After that, screw the adjusting ring 800 into the positioning ring 400 and lock it with screws. And install the positioning ring 400 on the piston rod 200 so that the positioning ring 400 abuts against the pressure piston 520. Then install the thrust ring 300 on the piston rod 200. After that, screw the positioning ring 400 into the crosshead 100 until the adjusting ring 800 abuts against the crosshead 100. Refer to Figure 3 and Figure 4 As shown, at this time, the preliminary connection between the crosshead 100 and the piston rod 200 is completed.

[0035] Then, pressure is applied to the oil chamber 510 through the oil pump joint 540. Refer to Figure 3 and Figure 4 As shown, the pressure piston 520 will exert pressure to the left, and the pressure body 500 will exert pressure to the right, forcing the piston rod 200 to deform. Then, the lock nut 600 is rotated, and the follower ring 700 is driven by the lock nut 600 to approach the crosshead 100 until the follower ring 700 abuts against the crosshead 100.

[0036] Then, the oil chamber 510 is depressurized. After depressurization, the piston rod 200 will slowly recover after the high-pressure oil is depressurized. The pre-tightening force generated by the deformation of the piston rod 200 will act on the connecting thread between the pressure body 500 and the lock nut 600, preventing the relative rotation of the pressure body 500 and the lock nut 600, so that the required connection pre-tightening force is achieved between the piston rod 200 and the crosshead 100. And if the lock nut 600 has a tendency of axial offset, the lock nut 600 will cause the follower ring 700 to rotate relative to the lock nut 600, balancing the force on the lock nut 600, preventing the lock nut 600 from generating axial offset, and further preventing the piston rod 200 from bending, ensuring the normal use of the piston rod 200.

[0037] In this embodiment, a hydraulic connection fastening device for the crosshead of a BOG compressor further includes a manual ultra-high pressure oil pump, which is not shown in the figure. The manual ultra-high pressure oil pump is connected to the oil pump joint 540 through a hose.

[0038] Specifically, an oil passage is provided on the pressure body 500, and the oil pump joint 540 is communicated with the oil chamber 510 through the oil passage.

[0039] During use, the hose of the manual ultra-high pressure oil pump is connected to the oil pump joint 540, and then the handle of the manual ultra-high pressure oil pump is lifted to increase the pressure of the manual ultra-high pressure oil pump to 150 Mpa. Under the action of the high-pressure oil, refer to Figure 3 and Figure 4 As shown, at this time, the pressure piston 520 will exert pressure to the left, and the pressure body 500 will exert pressure to the right.

[0040] In this embodiment, the thrust ring 300 includes two ring bodies, both of which are semi-circular structures, and the two ring bodies are installed on the piston rod 200 through the first elastic member 310. The first elastic member 310 is an annular spring.

[0041] In this embodiment, the piston rod 200 includes a first rod body 210 and a second rod body 220. The first rod body 210 and the second rod body 220 are arranged in sequence in the first direction and fixedly connected. The first rod body 210 and the second rod body 220 are of an integrally formed structure. The first rod body 210 is an elastic rod, and the diameter of the first rod body 210 is smaller than that of the second rod body 220. The thrust ring 300, the positioning ring 400, and the pressure body 500 are all installed on the first rod body 210. A shoulder is provided at one end of the second rod body 220 close to the first rod body 210 in the first direction, and the pressure body 500 abuts against the shoulder.

[0042] Further, three positioning bosses 230 are provided on the first rod body 210. The three positioning bosses 230 are sequentially spaced along the first direction on the first rod body 210. The thrust ring 300 is installed on the positioning boss 230 on the side away from the second rod body 220 in the first direction, that is, on the positioning boss 230 at the end. The remaining two positioning bosses 230 are used to assist in positioning the adjusting ring 800 and the pressure body 500.

[0043] In a further embodiment, a limiting plate 710 is coaxially and fixedly provided on the follower ring 700. The limiting plate 710 is an arc-shaped plate. In the radial direction of the piston rod 200, the limiting plate 710 is located between the locking nut 600 and the pressure body 500, and the limiting plate 710 is in threaded fit with the pressure body 500.

[0044] Specifically, a chute 610 is provided on the inner peripheral wall surface of the locking nut 600. The limiting plate 710 is installed in the chute 610, and the thread on the limiting plate 710 can be connected with the thread on the inner peripheral wall surface of the locking nut 600, so that when the locking nut 600 is screwed into the pressure body 500, it will not affect the installation of the locking nut 600 on the pressure body 500.

[0045] In this embodiment, by providing the limiting plate 710, when the follower ring 700 rotates relative to the locking nut 600, the follower ring 700 will drive the limiting plate 710 to rotate synchronously, causing the thread on the limiting plate 710 to be misaligned with the thread on the pressure body 500, so that the limiting plate 710 and the pressure body 500 are stuck together, preventing relative rotation between the limiting plate 710 and the pressure body 500, and indirectly restricting the rotation of the locking nut 600 relative to the limiting plate 710, further improving the connection tightness between the crosshead 100 and the piston rod 200.

[0046] Combined with the above embodiments, the specific working process is as follows:

[0047] When connecting the piston rod 200 to the crosshead 100, first install the sealing ring 530 and the pressure piston 520 into the oil cavity 510 of the pressure body 500, and screw the lock nut 600 and the follower ring 700 onto the pressure body 500. Then install the pressure body 500 onto the first rod body 210 of the piston rod 200, and make the pressure body 500 abut against the shoulder of the second rod body 220 of the piston rod 200.

[0048] After that, screw the adjusting ring 800 into the positioning ring 400 and lock it with a screw. And install the positioning ring 400 onto the first rod body 210 of the piston rod 200, making the positioning ring 400 abut against the pressure piston 520. Then use the first elastic member 310 to lock and install the two ring bodies onto the piston rod 200 to complete the installation of the thrust ring 300.

[0049] After that, turn the adjusting ring 800 to screw the positioning ring 400 into the crosshead 100 until the adjusting ring 800 abuts against the crosshead 100. See Figure 3 and Figure 4 As shown, at this time, the preliminary connection between the crosshead 100 and the piston rod 200 is completed.

[0050] Connect the hose of the manual ultra-high pressure oil pump to the oil pump joint 540, then lift the handle of the manual ultra-high pressure oil pump to increase the pressure of the manual ultra-high pressure oil pump to 150 Mpa, and apply pressure to the oil cavity 510 through the oil pump joint 540. Under the action of the high-pressure oil, see Figure 3 and Figure 4 As shown, the pressure piston 520 will apply pressure to the left, and the pressure body 500 will apply pressure to the right, forcing the piston rod 200 to deform. Then turn the lock nut 600, and drive the follower ring 700 to approach the crosshead 100 through the lock nut 600 until the follower ring 700 abuts against the crosshead 100.

[0051] Then relieve the pressure on the oil cavity 510. After the pressure is relieved, the pre-tightening force generated by the deformation of the piston rod 200 will act on the connecting thread between the pressure body 500 and the lock nut 600, preventing the relative rotation between the pressure body 500 and the lock nut 600, so that the required connection pre-tightening force is achieved between the piston rod 200 and the crosshead 100. And if the lock nut 600 has a tendency of axial offset, the lock nut 600 will cause the follower ring 700 to rotate relative to the lock nut 600 to balance the force on the lock nut 600, prevent the lock nut 600 from generating axial offset, and further prevent the piston rod 200 from bending, ensuring the normal use of the piston rod 200.

[0052] When the follower ring 700 rotates relative to the lock nut 600, the follower ring 700 will drive the limit plate 710 to rotate synchronously, causing the threads on the limit plate 710 to be misaligned with the threads on the pressure body 500, so that the limit plate 710 and the pressure body 500 are locked together, preventing relative rotation between the limit plate 710 and the pressure body 500, and indirectly restricting the rotation of the lock nut 600 relative to the limit plate 710, further improving the connection tightness between the crosshead 100 and the piston rod 200.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydraulic connection fastening device for the crosshead of a BOG compressor, which is used to connect the crosshead and the piston rod, and is characterized in that: It includes a thrust ring, a positioning ring, a pressure body, a locking nut and a follower ring; the crosshead is located at one end of the piston rod, and the thrust ring, the positioning ring and the pressure body are arranged in sequence and coaxially on the piston rod along the first direction, and the first direction is the axial direction of the piston rod; the thrust ring is located on the side of the pressure body close to the crosshead in the first direction, the thrust ring abuts against the crosshead, the positioning ring is in threaded cooperation with the crosshead and abuts against the thrust ring, an adjusting ring is sleeved on the positioning ring, and the adjusting ring is in threaded cooperation with the positioning ring; an oil cavity is provided in the pressure body, a pressure piston and a sealing ring are arranged in sequence along the first direction in the oil cavity, the pressure piston is located on the side of the sealing ring close to the positioning ring in the first direction, and the pressure piston abuts against the positioning ring; an oil pump joint is provided on the pressure body, and the oil pump joint is communicated with the oil cavity; the follower ring and the locking nut are arranged in sequence and coaxially in the first direction, the follower ring is located on the side of the locking nut close to the crosshead in the first direction and can abut against the crosshead, the locking nut is sleeved on the pressure body and is in threaded cooperation with the pressure body, and the locking nut is spherically hinged with the follower ring; a limiting plate is coaxially and fixedly arranged on the follower ring, the limiting plate is an arc-shaped plate, in the radial direction of the piston rod, the limiting plate is located between the locking nut and the pressure body, and the limiting plate is in threaded cooperation with the pressure body; a chute is opened on the inner peripheral wall surface of the locking nut, the limiting plate is installed in the chute, and the thread on the limiting plate can be connected with the thread on the inner peripheral wall surface of the locking nut. If the locking nut has a tendency of axial offset, the locking nut will cause the follower ring to rotate relative to the locking nut to balance the force on the locking nut and prevent the locking nut from generating axial offset.

2. The crosshead hydraulic connection fastening device of a BOG compressor according to claim 1, characterized in that: The piston rod includes a first rod body and a second rod body, the first rod body and the second rod body are arranged in sequence and fixedly connected in the first direction, the first rod body is an elastic rod, and the diameter of the first rod body is smaller than that of the second rod body. The thrust ring, the positioning ring and the pressure body are all installed on the first rod body. A shoulder is arranged at one end of the second rod body close to the first rod body in the first direction, and the pressure body abuts against the shoulder.

3. The crosshead hydraulic connection fastening device of a BOG compressor according to claim 2, characterized in that: Three positioning bosses are arranged at intervals along the first direction on the first rod body.

4. A crosshead hydraulic connection fastening device for a BOG compressor according to claim 1, characterized in that: The thrust ring includes two ring bodies, both of the two ring bodies are semi-circular structures, and the two ring bodies are installed on the piston rod through a first elastic member.

5. The crosshead hydraulic connection fastening device of a BOG compressor according to claim 4, characterized in that: The first elastic member is an annular spring.

6. The crosshead hydraulic connection fastening device of a BOG compressor according to claim 1, characterized in that: It further includes a manual ultra-high pressure oil pump, and the manual ultra-high pressure oil pump is connected to the oil pump joint through a hose.

7. The crosshead hydraulic connection fastening device of a BOG compressor according to claim 6, characterized in that: An oil passage is opened on the pressure body, and the oil pump joint is communicated with the oil cavity through the oil passage.

8. A crosshead hydraulic connection fastening device for a BOG compressor according to claim 1, characterized in that: The adjusting ring and the positioning ring are connected by screws.

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