A centering and tensioning tool for heat exchange tubes and tube sheet holes

Abstract

The present invention relates to an alignment and tensioning tool for a heat exchange tube and a tube sheet hole, which comprises an oil cylinder with a right piston and a left piston, a pull rod connected to the right piston, and a positioning sleeve connected to the left piston. The right piston and the left piston divide the oil cylinder into three working chambers, and oil inlet and outlet ports are respectively arranged on the working chambers, so that the right piston and the left piston can move through the three working chambers; the positioning sleeve is movably sleeved on the pull rod, and a sliding fit is provided between the positioning sleeve and the pull rod. A clearance fit is provided between the outer diameter of the positioning sleeve and the inner diameter of the tube sheet hole, the inner diameter of the heat exchange tube hole, and between the outer diameter of the head of the pull rod and the inner diameter of the heat exchange tube hole; a expanding sleeve is installed on the pull rod between the head of the pull rod and the head of the positioning sleeve. The expanding sleeve is restricted on the pull rod by the end face of the head of the pull rod, which can reduce the labor intensity, improve the work efficiency, and realize the rapid alignment and close welding of the end face of the heat exchange tube hole and the end face of the tube sheet hole.

Description

Technical Field

[0001] The present invention belongs to the technical field of manufacturing shell-and-tube and spiral-wound heat exchangers, and particularly relates to a centering and tensioning tool for heat exchange tubes and tube sheet holes, which can center and tension the heat exchange tubes and tube sheet holes when butt-welding the tube sheet of the heat exchanger and the heat exchange tubes. Background Art

[0002] During the research and development of the "National Key Research and Development Program (2018YFB1900501)" undertaken by Tsinghua University, a spiral-wound heat exchanger with a butt-weld form was encountered. In shell-and-tube and spiral-wound heat exchange equipment, the orifice of the tube sheet and the end of the heat exchange tube adopt a butt-weld form, which has the advantages of high weld strength and strong corrosion resistance. When butt-welding the tube sheet of the heat exchanger and the heat exchange tubes, if the distance between the heat exchange tubes is very small, internal hole welding must be used. To ensure the welding quality, first, the orifice of the heat exchange tube needs to be centered with the orifice of the tube sheet; second, the gap between the end face of the orifice of the heat exchange tube and the end face of the orifice of the tube sheet needs to be eliminated, that is, the heat exchange tube and the tube sheet need to be positioned. When the number of heat exchange tubes is large, to improve the welding production efficiency, certain requirements are also put forward for shortening the assembly time of the heat exchange tubes and the tube sheet. Therefore, there are currently disadvantages such as large welding workload, low welding quality, poor welding accuracy, high labor intensity, and low efficiency at the end face of the orifice of the heat exchange tube and the end face of the orifice of the tube sheet. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a centering and tensioning tool for heat exchange tubes and tube sheet holes that can reduce labor intensity, improve work efficiency, and achieve centering, then close contact, and finally welding of the end face of the tube hole of the heat exchange tube and the end face of the tube sheet hole to meet the welding accuracy requirements. This tool passes through the tube sheet hole and is inserted into the tube hole of the heat exchange tube, can first uniformly tighten the heat exchange tube, and after tightening, axially tension it, center the tube hole of the heat exchange tube and press it against the tube sheet hole to achieve rapid positioning of the tube sheet hole and the heat exchange tube.

[0004] The purpose of the present invention is achieved as follows: A centering and tensioning tool for heat exchange tubes and tube sheet holes includes an oil cylinder with a double-piston structure having a right piston and a left piston as the power, a pull rod connected to the right piston, and a positioning sleeve connected to the left piston. The right piston and the left piston divide the oil cylinder into three working chambers, and oil inlet and outlet ports are respectively provided on these three working chambers. Through these three working chambers with oil inlet and outlet ports, the right piston and the left piston can move separately or together; the positioning sleeve is movably sleeved on the pull rod, and the positioning sleeve and the pull rod are in sliding fit. There is a clearance fit between the outer diameter of the positioning sleeve and the inner diameter of the hole of the tube sheet, the inner diameter of the tube hole of the heat exchange tube, and between the outer diameter of the head of the pull rod and the inner diameter of the tube hole of the heat exchange tube; a expanding sleeve is installed on the pull rod between the head of the pull rod and the head of the positioning sleeve, and the expanding sleeve sleeved on the pull rod is restricted on the pull rod by the end face of the head of the pull rod.

[0005] The movement of the right piston and the left piston is hydraulically controlled. After inserting the tool into the holes of the tube sheet and the tube holes of the heat exchange tubes, oil is fed into the B oil inlet and outlet of the oil cylinder, and the other oil ports return oil. The left piston drives the positioning sleeve to generate an axial force to the left, and the right piston drives the pull rod to generate an axial force to the right. The two axial forces jointly press on the two end faces of the expanding sleeve through the end face of the head of the positioning sleeve and the end face of the head of the pull rod. The expanding sleeve sleeved on the pull rod generates an outward radial deformation due to the small inward deformation space, and presses against the hole wall of the heat exchange tube; the right piston, the left piston, the expanding sleeve, the positioning sleeve, the pull rod, and the heat exchange tube are connected together under the tightening force of the expanding sleeve to form a whole, ensuring the coaxiality of the tube holes of the heat exchange tubes and the holes of the tube sheet;

[0006] When the expanding sleeve is tightened with the heat exchange tube, oil is fed into the A oil inlet and outlet of the oil cylinder, and the other oil ports return oil. The left side of the left piston is stressed, driving the right piston, the pull rod, and the heat exchange tube tightened on the pull rod to move to the right together. There is a support sleeve supported between the tube sheet and the oil cylinder. Under the support of the support sleeve, there is no relative movement between the tube sheet and the oil cylinder. At this time, the heat exchange tube is pulled towards the tube sheet, realizing the centering and close fitting of the end face of the tube hole of the heat exchange tube and the end face of the hole of the tube sheet, and realizing the positioning of the tube sheet and the heat exchange tube;

[0007] After spot welding the tube sheet and the heat exchange tubes together, oil is fed into the C oil inlet and outlet of the oil cylinder, and the other oil ports return oil. The right piston is stressed to the left, driving the pull rod to move to the left. The stress on the end face of the expanding sleeve disappears and it returns to its original shape. The expanding sleeve is disengaged from the inner wall of the heat exchange tube. The right piston drives the left piston to continue moving to the left end of the oil cylinder, restoring the initial position of the piston. At this time, the tool is taken out from the hole of the tube sheet. The right piston and the left piston are in the extended state, and the end face of the expanding sleeve is not stressed and is in a free state.

[0008] Furthermore, the pull rod and the piston rod of the right piston are connected by threads, and the positioning sleeve and the piston rod of the left piston are also connected by threads.

[0009] Furthermore, a spacer sleeve is also provided between the expanding sleeves sleeved between the end face of the head of the positioning sleeve and the end face of the head of the pull rod. The spacer sleeve and the expanding sleeves are alternately sleeved on the pull rod and are in sliding fit on the pull rod.

[0010] Furthermore, the material of the expanding sleeve is rubber. When the two end faces are subjected to axial extrusion force, the expanding sleeve will undergo radial deformation and generate radial force. By increasing the number of expanding sleeves, the friction force generated by tightening can be doubled under a certain axial pressing force on the expanding sleeve, ensuring a more reliable tightened connection between the heat exchange tube and the pull rod.

[0011] Furthermore, the outer diameters of the spacer sleeve and the expansion sleeve are determined according to the pore diameter size of the heat exchange tube, and the outer diameter of the positioning sleeve is determined according to the pore diameter of the tube sheet, and all adopt clearance fits; the lengths of the support sleeve, the positioning sleeve, and the pull rod are determined according to the thickness of the tube sheet. The length of the positioning sleeve is greater than the thickness of the tube sheet. When both the left piston and the right piston are at the left end of the oil cylinder, the expansion sleeve is in a free state, and the tightening and tensioning actions can be achieved within the effective stroke of the piston.

[0012] The present invention has the following positive effects: This tool first passes through the tube sheet hole and is inserted into the tube hole of the heat exchange tube, then uniformly tightens the heat exchange tube for quick centering, and then axially tensions the heat exchange tube after tightening it, quickly pressing the tube hole of the heat exchange tube onto the tube sheet hole to achieve quick centering and positioning fit between the tube sheet hole and the heat exchange tube. Therefore, the present invention can significantly reduce the labor intensity, improve the work efficiency, realize the quick production process of first centering, then sticking, and then welding the end faces of the tube hole of the heat exchange tube and the tube sheet hole, meet the welding precision requirements, and enable the heat exchange tube and the tube sheet hole to be quickly centered, quickly tightened, and quickly welded. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of a butt joint between the orifice of the tube sheet of a heat exchanger and the orifice of the heat exchange tube.

[0014] Figure 2 is the structural and working principle diagram of the centering and tensioning device of the present invention.

[0015] Figure 3 is a partial enlarged view of the structure between the positioning sleeve, the pull rod, the expansion sleeve, and the spacer sleeve in the comparative document of the tightening part of the present invention.

[0016] In the figure, 1. A heat exchanger with a butt joint weld form, 2. Heat exchange tube, 3. Tube sheet, 4. Centering and tensioning device, 5. Oil cylinder, 6. Right piston, 7. Left piston, 8. Support sleeve, 9. Positioning sleeve, 10. Spacer sleeve, 11. Expansion sleeve, 12. Pull rod. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] As Figure 1 shown, Figure 1 is a schematic diagram of a heat exchanger with a butt joint weld between the tube sheet and the heat exchange tube. During welding, the welding torch passes through the tube sheet hole and extends into the inner hole of the heat exchange tube for rotary welding; therefore, before welding, first, the holes of the heat exchange tube 2 and the tube sheet 3 need to be centered, and second, the end face of the heat exchange tube 2 needs to be tightly attached to the orifice end face of the tube sheet 3. After centering and tightly attaching the holes of the heat exchange tube 2 and the tube sheet 3, the heat exchange tube 2 and the tube sheet 3 are spot-welded together. Then, the inner hole rotary welding process can be carried out, which has the defects of low efficiency and poor welding precision.

[0018] As Figure 2 , 3 shown, Figure 2This is the schematic diagram of the tool of the present invention. The material of the expansion sleeve 11 is rubber. When axial extrusion forces are applied to both end faces, the expansion sleeve 11 will undergo radial deformation and generate radial forces. The oil cylinder used as the power adopts a double-piston structure. The right piston 6 is connected to the pull rod 12, and the left piston 7 is connected to the positioning sleeve 9. The oil cylinder 5 has three oil inlets and outlets, enabling the right piston 6 and the left piston 7 to move independently or together.

[0019] Therefore, a centering and tensioning tool for a heat exchange tube and a tube plate hole disclosed by the present invention includes an oil cylinder 5 with a double-piston structure having a right piston 6 and a left piston 7 as the power, a pull rod 12 connected to the right piston 6, and a positioning sleeve 9 connected to the left piston 7. The right piston 6 and the left piston 7 form a double-piston structure and can move left and right in the oil cylinder 5. The piston rod of the right piston 6 is sleeved in the piston rod of the left piston 7, and at the same time, the piston rod of the right piston 6 can move left and right in the piston rod of the left piston 7. The piston rod of the right piston 6 is a piston rod with a step, and this step limits the stroke of the piston rod of the right piston 6 to ensure the existence of the middle working chamber. The piston rod of the left piston 7 is also a piston rod with a step, and this step limits the stroke of the piston rod of the right piston 7 to ensure the existence of the left working chamber.

[0020] The right piston 6 and the left piston 7 divide the oil cylinder 5 into three working chambers, and oil inlets and outlets are respectively opened on these three working chambers, namely three oil inlets and outlets A, B, and C; through these three working chambers with oil inlets and outlets, the right piston 6 and the left piston 7 can move independently or together; the positioning sleeve 9 is movably sleeved on the pull rod 12, and the positioning sleeve 9 and the pull rod 12 are in sliding fit. The outer diameter of the positioning sleeve 9 has a clearance fit with the inner diameter of the hole of the tube plate 3 and the inner diameter of the tube hole of the heat exchange tube 2, and the outer diameter of the head of the pull rod 12 has a clearance fit with the inner diameter of the tube hole of the heat exchange tube 2; an expansion sleeve 11 is installed on the pull rod 12 between the head of the pull rod 12 and the head of the positioning sleeve 9, and the expansion sleeve 11 sleeved on the pull rod 12 is restricted on the pull rod 12 by the end face of the head of the pull rod 12.

[0021] The movement of the pistons is hydraulically controlled, and the initial positions of the two pistons are at the left end of the oil cylinder. That is, the movement of the right piston 6 and the left piston 7 is hydraulically controlled. After inserting the tool into the hole of the tube plate 3 and the tube hole of the heat exchange tube 2, oil is fed into the B oil inlet and outlet of the oil cylinder 5, and the other oil inlets and outlets return oil. The left piston 7 drives the positioning sleeve 9 to generate an axial force to the left, and the right piston 6 drives the pull rod 12 to generate an axial force to the right. The two axial forces press on both end faces of the expansion sleeve 11 through the end face of the head of the positioning sleeve 9 and the end face of the head of the pull rod 12. The expansion sleeve 11 sleeved on the pull rod 12 generates an outward radial deformation because the inward deformation space is small, and presses against the hole wall of the heat exchange tube 2; the right piston 6, the left piston 7, the expansion sleeve 11, the positioning sleeve 9, the pull rod 12, and the heat exchange tube 2 are connected together under the tightening force of the expansion sleeve 11 to form a whole, ensuring the coaxiality of the tube hole of the heat exchange tube 2 and the hole of the tube plate 3;

[0022] After the expansion sleeve 11 is tightened with the heat exchange tube 2, the A oil inlet and outlet of the oil cylinder 5 are supplied with oil, and the other oil ports return oil. The left side of the left piston 7 is stressed, driving the right piston 6, the pull rod 12, and the heat exchange tube 2 tightened by the pull rod 12 to move to the right together. There is a support sleeve 8 supported between the tube sheet 3 and the oil cylinder 5. Under the support of the support sleeve 8, there is no relative movement between the tube sheet 3 and the oil cylinder 5. At this time, the heat exchange tube 2 is pulled towards the tube sheet 3, realizing the centering and tight fitting of the hole end face of the heat exchange tube 2 and the hole end face of the tube sheet 3, and realizing the positioning of the tube sheet 3 and the heat exchange tube 2;

[0023] After spot welding the tube sheet 3 and the heat exchange tube 2 together, the C oil inlet and outlet of the oil cylinder 5 are supplied with oil, and the other oil ports return oil. The right piston 6 is stressed to the left, driving the pull rod 12 to move to the left. The force on the end face of the expansion sleeve 11 disappears and it returns to its original shape, disengaging from the inner wall of the heat exchange tube 2. The right piston 6 drives the left piston 7 to continue moving to the left end of the oil cylinder, restoring the initial position of the piston. At this time, this tool is taken out from the hole of the tube sheet 3. The right piston 6 and the left piston 7 are in the extended state, and the end face of the expansion sleeve 11 is not stressed and is in a free state.

[0024] The pull rod 12 is threadedly connected to the piston rod of the right piston 6, and the positioning sleeve 9 is also threadedly connected to the piston rod of the left piston 7.

[0025] A spacer sleeve 10 is also provided between the expansion sleeves 11 sleeved between the head end face of the positioning sleeve 9 and the head end face of the pull rod 12. The spacer sleeve 10 and the expansion sleeves 11 are spaced and sleeved on the pull rod 12, and are in a sliding fit on the pull rod 12.

[0026] The material of the expansion sleeve 11 is rubber. When axial extrusion forces are applied to both end faces, the expansion sleeve will undergo radial deformation and generate radial forces. By increasing the number of expansion sleeves 11, the friction force generated by tightening can be doubled under a certain axial compression force on the expansion sleeve 11, ensuring a more reliable tight connection between the heat exchange tube 2 and the pull rod 12.

[0027] The outer diameters of the spacer sleeve 10 and the expansion sleeves 11 are determined according to the tube hole diameter size of the heat exchange tube 2, and the outer diameter of the positioning sleeve 9 is determined according to the hole diameter of the tube sheet 3, and all adopt clearance fits; the lengths of the support sleeve 8, the positioning sleeve 9, and the pull rod 12 are determined according to the thickness of the tube sheet 3. The length of the positioning sleeve 9 is greater than the thickness of the tube sheet 3. When both the left piston 7 and the right piston 6 are at the left end of the oil cylinder 5, the expansion sleeve 11 is in a free state, and the tightening and tensioning actions can be realized within the effective stroke of the piston.

[0028] As Figure 3As shown, the expansion sleeve 11 and the spacer sleeve 10 are sleeved on the pull rod 12 with a sliding fit. The pull rod 12 is connected to the piston rod of the right piston 6 by threads. The positioning sleeve 9 is connected to the piston rod of the left piston 7 by threads. The positioning sleeve 9 is also sleeved on the pull rod 12 with a sliding fit, and its outer diameter has a clearance fit with the holes of the tube sheet 3 and the heat exchange tube 2. The expansion sleeves 11 and the spacer sleeves 10 are alternately sleeved on the pull rod 12 with a sliding fit. By increasing the number of expansion sleeves 11, when the axial compression force on the expansion sleeve 11 is certain, the frictional force generated by tightening can be increased several times, making the tight connection between the heat exchange tube 2 and the pull rod 12 and other components more reliable.

[0029] As Figure 2 , 3 shown, first, this tool needs to be inserted through the tube sheet holes on the other side of the tube sheet 3, and then the heat exchange tube 2 with a flat tube end is inserted into the tightening part of this tool. The oil cylinder of this tool needs to be used with a small oil station. After inserting this tool into the tube sheet 3 and the heat exchange tube 2, make the B port of the oil cylinder 5 intake oil, and the A and C ports return oil. The right piston 6 drives the pull rod 12 to retract, and both end faces of the expansion sleeve 11 are pressed, expanding radially to tightly squeeze the inner hole of the heat exchange tube 2. At this time, under the action of the tightening force, the right piston 6, the left piston 7, and the heat exchange tube 2 form a whole.

[0030] When the expansion sleeve 11 is tightened with the heat exchange tube 2, the A port of the oil cylinder 5 intakes oil, and the left side of the left piston 7 is stressed, driving the whole formed by the right piston 6 and other components and the heat exchange tube 2 to move to the right together. The support sleeve 8 supports between the tube sheet 3 and the oil cylinder 5. Under the support of the support sleeve 8, the tube sheet 3 and the oil cylinder 5 cannot move relative to each other. At this time, the heat exchange tube 2 is pulled towards the tube sheet 3, realizing that the orifice end face of the heat exchange tube 2 is centered and tightly attached to the orifice end face of the tube sheet 3.

[0031] After spot welding the tube sheet 3 and the heat exchange tube 2 together, the oil station works. The C port of the oil cylinder 5 intakes oil, and the A and B ports return oil. The right piston 6 is stressed to the left, driving the pull rod 12 to move to the left. The stress on the end face of the expansion sleeve 11 disappears and it returns to its original shape, disengaging from the inner wall of the heat exchange tube 2. The right piston 6 drives the left piston 7 to continue moving to the left end of the oil cylinder, restoring the initial position of the piston. At this time, this tool can be taken out from the hole of the tube sheet 3. At this time, the left piston 7 and the right piston 6 are in the extended state, and the end face of the expansion sleeve 11 is not stressed and is in a free state.

[0032] By operating in this way repeatedly, the heat exchange tube 2 can be welded to the tube sheet 3 one by one by electric welding.

[0033] In this tool, the support sleeve 8, positioning sleeve 9, spacer sleeve 10, expansion sleeve 11, and pull rod 12 are replaceable parts. The outer diameters of the spacer sleeve 10 and expansion sleeve 11 are determined according to the pore size of the heat exchange tube 2, and the outer diameter of the positioning sleeve 9 is determined according to the pore size of the tube sheet 3, and all adopt clearance fits. The lengths of the support sleeve 8, positioning sleeve 9, and pull rod 12 are determined according to the thickness of the tube sheet 3. It should be noted that when the left piston 7 and right piston 6 are both at the left end of the oil cylinder 5, the expansion sleeve 11 is in a free state, and the tightening and tensioning actions can be achieved within the effective stroke of the piston.

Claims

1. A centering and tensioning tool for heat exchange tubes and tube sheet holes, comprising an oil cylinder with a double-piston structure having a right piston and a left piston as the power source, a pull rod connected to the right piston, and a positioning sleeve connected to the left piston. Characterized in that, The right piston and the left piston divide the oil cylinder into three working chambers, and oil inlets and outlets are respectively provided on the three working chambers. Through the three working chambers with oil inlets and outlets, the right piston and the left piston can move separately or together; the positioning sleeve is movably sleeved on the pull rod, and the positioning sleeve and the pull rod are in sliding fit. There is a clearance fit between the outer diameter of the positioning sleeve and the inner diameter of the hole of the tube sheet, the inner diameter of the tube hole of the heat exchange tube, and between the outer diameter of the head of the pull rod and the inner diameter of the tube hole of the heat exchange tube; a expanding sleeve is installed on the pull rod between the head of the pull rod and the head of the positioning sleeve, and the expanding sleeve sleeved on the pull rod is restricted on the pull rod by the end face of the head of the pull rod. The movement of the right piston and the left piston is controlled by hydraulic pressure. After inserting the tool into the hole of the tube sheet and the tube hole of the heat exchange tube, oil is fed into the B oil inlet and outlet of the oil cylinder, and the other oil ports return oil. The left piston drives the positioning sleeve to generate an axial force to the left, and the right piston drives the pull rod to generate an axial force to the right. The two axial forces press on both end faces of the expanding sleeve through the end face of the head of the positioning sleeve and the end face of the head of the pull rod. The expanding sleeve sleeved on the pull rod generates an outward radial deformation due to the small deformation space generated inward and presses against the hole wall of the heat exchange tube; the right piston, the left piston, the expanding sleeve, the positioning sleeve, the pull rod, and the heat exchange tube are connected together under the tightening force of the expanding sleeve to form a whole, ensuring the coaxiality between the tube hole of the heat exchange tube and the hole of the tube sheet. When the expanding sleeve is tightened with the heat exchange tube, oil is fed into the A oil inlet and outlet of the oil cylinder, and the other oil ports return oil. The left side of the left piston is stressed, driving the right piston, the pull rod, and the heat exchange tube tightened on the pull rod to move to the right together. A support sleeve is supported between the tube sheet and the oil cylinder. Under the support of the support sleeve, there is no relative movement between the tube sheet and the oil cylinder. At this time, the heat exchange tube is pulled towards the tube sheet, realizing the centering and close contact of the end face of the tube hole of the heat exchange tube and the end face of the hole of the tube sheet, and realizing the positioning of the tube sheet and the heat exchange tube. After spot welding the tube sheet and the heat exchange tube together, oil is fed into the C oil inlet and outlet of the oil cylinder, and the other oil ports return oil. The right piston is stressed to the left, driving the pull rod to move to the left. The stress on the end face of the expanding sleeve disappears and returns to its original shape, disengaging from the inner wall of the heat exchange tube. The right piston drives the left piston to continue moving to the left end of the oil cylinder, restoring the initial position of the piston. At this time, the tool is taken out from the hole of the tube sheet. The right piston and the left piston are in the extended state, and the end face of the expanding sleeve is not stressed and is in a free state.

2. A centering and tensioning tool for heat exchange tubes and tube sheet holes according to claim 1, Characterized in that, The pull rod and the piston rod of the right piston are connected by threads, and the positioning sleeve and the piston rod of the left piston are also connected by threads.

3. A centering and tensioning tool for heat exchange tubes and tube sheet holes according to claim 1, Characterized in that, A spacer sleeve is further provided between the expanding sleeves sleeved between the end face of the head of the positioning sleeve and the end face of the head of the pull rod. The spacer sleeve and the expanding sleeve are alternately sleeved on the pull rod and are in sliding fit on the pull rod.

4. A centering and tensioning tool for heat exchange tubes and tube sheet holes according to claim 3, Characterized in that, The material of the expansion sleeve is rubber. When axial extrusion forces are applied to both end faces, the expansion sleeve will undergo radial deformation, generating radial forces. By increasing the number of expansion sleeves, the friction force generated by tightening can be doubled under the condition of a certain axial compression force on the expansion sleeve, ensuring a more reliable tight connection between the heat exchange tube and the pull rod.

5. A heat exchange tube and tube sheet hole centering and tightening tool according to claim 4, characterized in that the outer diameters of the spacer sleeve and the expansion sleeve are determined according to the hole diameter size of the heat exchange tube, and the outer diameter of the positioning sleeve is determined according to the hole diameter of the tube sheet, and all adopt clearance fits; the lengths of the support sleeve, the positioning sleeve, and the pull rod are determined according to the thickness of the tube sheet. The length of the positioning sleeve is greater than the thickness of the tube sheet. When both the left piston and the right piston are at the left end of the oil cylinder, the expansion sleeve is in a free state, and the tightening and pulling actions can be achieved within the effective stroke of the piston.

Images