Improved method for controlling the pressure of the hydraulic circuit of the press wheel of a pipe-casting cement lining machine

Abstract

The application discloses an improved method of hydraulic circuit of a pressure wheel of a cast pipe cement lining machine, and relates to the technical field of hydraulic control systems. The hydraulic control system of the pressure wheel of the cast pipe cement lining machine comprises a pressure wheel hydraulic cylinder and an original hydraulic circuit, and the structure of the whole system is as follows: a one-way valve, an electromagnetic reversing valve, a pressure reducing valve and a pressure measuring device are sequentially connected to the B port of the existing pressure wheel hydraulic cylinder. The improved method of the hydraulic control system of the pressure wheel of the cast pipe cement lining machine utilizes the rodless cavity back pressure of the pressure wheel hydraulic circuit to realize the balance of the weight of the pressure wheel mechanism, the pressure of the hydraulic cylinder and the extrusion of the pipe, so that the pipe is prevented from being crushed, the speed of the centrifugal process of the pipe is increased, the operation of the pressure wheel is controlled when the pressure is too large, and the crushed waste caused by the radial jumping extrusion of the pipe is reduced.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control system technology, specifically to an improved method for controlling the hydraulic circuit of the pressure roller in a cement lining casting machine. Background Technology

[0002] The cement lining machine for cast iron pipes transports the pipes filled with mortar to the centrifugal station, where two sets of support rollers and pressure rollers clamp the pipes to form a centrifugal mechanism. The motor drives the pressure rollers to rotate the pipes, and the centrifugal force generated by the high-speed rotation of the pipes causes the water in the mortar to be separated and tightly adhered to the inner wall of the pipe to form a lining.

[0003] In the existing technology, the operator needs to operate the manual directional valve to drive the hydraulic cylinder to lift and lower, so that the pressure roller hydraulic cylinder applies a certain pressure to the pipe to ensure the stability of the pipe body when it rotates centrifugally. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides an improved method for the hydraulic circuit controlling the pressure of the pressure roller in a cement lining machine for cast pipes. This method solves the problem in existing technologies where the operator needs to manually operate a directional valve to quickly stop the pressure roller just as it approaches the pipe, ensuring the roller stays close to the pipe without pressing too hard, thus preventing excessive pressure during descent and rotation that could flatten the pipe and cause defects. Furthermore, the pressure roller mechanism's own weight combined with the hydraulic cylinder pressure necessitates multiple adjustments during actual operation, affecting efficiency and inevitably leading to pipe flattening.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a hydraulic control system for the pressure roller of a cement lining machine for cast pipes, comprising a pressure roller hydraulic cylinder and an existing hydraulic circuit, the structure of which is as follows:

[0008] The existing hydraulic cylinder of the pressure roller is connected in sequence to a check valve, a solenoid directional valve, a pressure reducing valve, and a pressure measuring device at port B.

[0009] A pressure reducing valve is connected in series between port A of the existing manual directional valve and port A1 of the hydraulic cylinder, which can adjust and reduce the downward pressure of the pressure roller cylinder.

[0010] The existing pressure roller hydraulic cylinder has a pressure reducing valve connected in series at port A2, and a hydraulic lock and a directional valve connected in parallel. During use, when there is back pressure at port B of the pressure roller cylinder, the solenoid directional valve will be briefly energized, thereby releasing the pressure at port A2 and reducing the pressure of the pressure roller hydraulic cylinder on the pipe body. The hydraulically controlled check valve is controlled by the solenoid directional valve and is used for brief pressure relief when the pressure in the rod chamber exceeds the limit during pipe rotation. The pressure reducing valve's port A1 is connected to the original pressure roller hydraulic cylinder's port A and is used to adjust and reduce the pressure of the rod chamber of the pressure roller hydraulic cylinder on the pipe body.

[0011] An improved method for controlling the hydraulic circuit of the pressure roller in a cast pipe cement lining machine includes the aforementioned hydraulic control system for the pressure roller of the cast pipe cement lining machine. The improved operation is as follows:

[0012] A pressure reducing valve is added to the rod chamber of the pressure roller to reduce the system pressure of 100 kg to near zero, so that the pressure roller mechanism can descend by its own weight, eliminating the pressure of the hydraulic cylinder on the pipe.

[0013] A bypass interface is added to the rodless chamber of the pressure roller, and the pressure oil connected to port P forms a return oil back pressure circuit when the pressure roller descends.

[0014] During use, in the initial stage of the pressure roller's descent, the pressure reducing valve reduces the hydraulic cylinder's downward pressure to zero, the solenoid directional valve is de-energized, and the return oil from the pressure roller's hydraulic cylinder descent returns directly through the original manual directional valve. The pressure roller mechanism achieves rapid descent by its own weight.

[0015] When the pressure roller approaches the pipe, the photoelectric limit sensor sends a signal, energizing the solenoid valve. The pressure reducing valve sets the pressure, and the solenoid directional valve and check valve enter the rodless chamber of the hydraulic cylinder to create hydraulic resistance back pressure, slowing down the descent speed of the pressure roller. This allows the operator to precisely control the stopping position of the pressure roller. At the same time, the return oil back pressure also balances part of the pressure roller's own weight, making the pipe less likely to be flattened.

[0016] When the pressure roller reaches the predetermined position, the operator returns the manual directional valve to the neutral position. When the pipe rotates centrifugally, the solenoid valve continues to be energized. The pressure oil forms a back pressure between the manual directional valve and the rodless chamber of the hydraulic cylinder through the check valve, the solenoid directional valve and the pressure reducing valve. This back pressure will partially offset the pressure on the pipe caused by the weight of the pressure roller, so that the pipe will not be flattened when it rotates radially.

[0017] To prevent the upward force generated by excessive radial runout during pipe rotation from increasing pressure in the rod chamber and damaging the pipe, a control loop is added to the rod chamber. When the pressure measuring device detects the set pressure limit, it sends a signal to briefly energize the single solenoid directional valve, opening the hydraulic lock to release this pressure. This further reduces the risk of excessive pressure from the pressure rollers causing pipe flattening.

[0018] (III) Beneficial Effects

[0019] This invention provides an improved method for controlling the hydraulic circuit of the pressure roller in a cement lining machine for cast pipes. It has the following beneficial effects:

[0020] The hydraulic circuit for controlling the pressure of the pressure roller in this cement lining pipe casting machine uses a pressure reducing valve to lower the secondary pressure of the pressure roller hydraulic circuit. By utilizing the back pressure of the pressure roller hydraulic circuit, the weight of the pressure roller mechanism and the pressure of the hydraulic cylinder are balanced to compress the pipe, thereby preventing the pipe from being flattened and accelerating the centrifugal process. Excessive pressure from the pressure roller is controlled, and the flattened waste caused by radial runout of the pipe during rotation is reduced. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] In this diagram, dashed lines represent existing hydraulic circuits, solid lines represent added hydraulic circuits, letters represent corresponding interfaces, and serial numbers represent valves with corresponding serial numbers.

[0023] 01. Solenoid directional valve; 02. Pressure measuring device; 03. Hydraulic check valve; 04. Pressure reducing valve; 05. Solenoid directional valve; 06. Check valve; 07. Pressure reducing valve. Detailed Implementation

[0024] 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.

[0025] Please see Figure 1 This invention provides a technical solution: a hydraulic control system for the pressure roller of a cement lining casting machine, including a pressure roller hydraulic cylinder and an existing hydraulic circuit. The structure of the entire system is as follows:

[0026] The B port of the existing pressure roller hydraulic cylinder is connected in sequence to a check valve 06, a solenoid directional valve 05, a pressure reducing valve 04, and a pressure measuring device.

[0027] A pressure reducing valve 07 is connected in series between the A port of the existing manual directional valve and the A1 port of the hydraulic cylinder, which can adjust and reduce the downward pressure of the pressure roller cylinder.

[0028] The existing pressure roller hydraulic cylinder has a pressure reducing valve 07 connected in series at port A2, and a hydraulic lock 03 and a directional valve 01 connected in parallel. During use, when there is back pressure at port B of the pressure roller cylinder, the solenoid directional valve 01 will be briefly energized, thereby releasing the pressure at port A2 and reducing the pressure of the pressure roller hydraulic cylinder on the pipe body. The hydraulic control check valve 03 is controlled by the solenoid directional valve 01 and is used for brief pressure relief when the pressure in the rod chamber exceeds the limit during pipe rotation. The pressure reducing valve 07 is connected to port A of the original pressure roller hydraulic cylinder and is used to adjust and reduce the pressure of the rod chamber of the pressure roller hydraulic cylinder on the pipe body.

[0029] An improved method for the hydraulic circuit of the pressure control roller of a cement lining machine for cast pipes includes the aforementioned hydraulic control system for the pressure roller of the cement lining machine for cast pipes. The improved operation is as follows:

[0030] A pressure reducing valve is added to the rod chamber of the pressure roller to reduce the system pressure of 100 kg to near zero, so that the pressure roller mechanism can descend by its own weight, eliminating the pressure of the hydraulic cylinder on the pipe.

[0031] A bypass interface is added to the rodless chamber of the pressure roller, and the pressure oil connected to port P forms a return oil back pressure circuit when the pressure roller descends.

[0032] During use, in the initial stage of the pressure roller's descent, the pressure reducing valve 07 reduces the hydraulic cylinder's downward pressure to zero, the solenoid directional valve 05 is de-energized, and the return oil from the pressure roller's hydraulic cylinder descent returns directly through the original manual directional valve. The pressure roller mechanism achieves rapid descent by its own weight.

[0033] When the pressure roller approaches the pipe, the photoelectric limit sensor sends a signal, energizing the solenoid valve 05. The pressure reducing valve 04 sets the pressure, and the solenoid directional valve 05 and check valve 06 enter the rodless chamber of the hydraulic cylinder to create hydraulic resistance back pressure, slowing down the descent speed of the pressure roller. This allows the operator to accurately control the stopping position of the pressure roller. At the same time, the return oil back pressure also balances part of the pressure roller's own weight, making the pipe less likely to be flattened.

[0034] When the pressure roller reaches the predetermined position, the operator returns the manual directional valve to the neutral position. When the pipe rotates centrifugally, the solenoid valve 05 continues to be energized. The pressure oil forms a back pressure between the manual directional valve and the rodless chamber of the hydraulic cylinder through the check valve 06, the solenoid directional valve 05 and the pressure reducing valve 04. This back pressure will partially offset the pressure on the pipe caused by the weight of the pressure roller, so that the pipe will not be flattened when it rotates radially.

[0035] To prevent excessive radial runout during pipe rotation from generating an upward force that could increase pressure in the rod chamber and damage the pipe, a control loop is added to the rod chamber. When pressure measuring device 02 detects the set pressure limit, it sends a signal to briefly energize the single solenoid directional valve 01, opening the hydraulic lock 03 to release this pressure. This further reduces the risk of excessive pressure from the pressure rollers causing pipe flattening.

[0036] In summary, the hydraulic circuit for controlling the pressure of the pressure roller in this cement lining pipe casting machine utilizes a pressure reducing valve to lower the secondary pressure of the pressure roller's hydraulic circuit. By using the back pressure of the pressure roller's hydraulic circuit, the weight of the pressure roller mechanism and the pressure of the hydraulic cylinder are balanced in their squeezing of the pipe, thereby preventing the pipe from being flattened and accelerating the centrifugal process. Excessive pressure from the pressure roller is controlled, and the amount of flattened waste caused by the radial runout of the rotating pipe is reduced.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An improved method for controlling the hydraulic circuit of the pressure roller in a cement lining machine for cast pipes, characterized in that: The hydraulic control system for the pressure roller of a cement pipe lining machine includes a pressure roller hydraulic cylinder and a hydraulic circuit. The rodless chamber port of the pressure roller hydraulic cylinder is connected to the B port of a manual directional valve, and the rod chamber port is connected to the A port of a manual directional valve. The manual directional valve has an O-type neutral position. The improved operation is as follows: A pressure reducing valve is added in series between the rod chamber port and the A port of the manual directional valve to reduce the system pressure from 100 kg to near zero pressure, allowing the pressure roller mechanism to descend solely by its own weight, eliminating the pressure of the pressure roller hydraulic cylinder on the pipe; a bypass port is added to the rodless chamber for bypassing... The interface is sequentially connected to a check valve, a solenoid directional valve, another pressure reducing valve, and a pressure measuring device. These components are connected in parallel with port B of the manual directional valve. During operation, in the initial stage of the pressure roller's descent, the pressure reducing valve connected to port A of the manual directional valve reduces the pressure in the pressure roller's hydraulic cylinder to zero. The solenoid directional valve is de-energized, and the rodless chamber directly returns oil through the manual directional valve. The pressure roller mechanism descends rapidly due to its own weight. When the pressure roller approaches the pipe, the photoelectric limit sensor sends a signal, energizing the solenoid directional valve. The pressure oil connected to the main inlet port P, after being pressure-adjusted by the other pressure reducing valve, enters the rodless hydraulic cylinder through the solenoid directional valve and the check valve. The hydraulic back pressure in the chamber slows down the descent of the pressure roller, allowing the operator to precisely control its stopping position. Simultaneously, the return oil back pressure balances part of the pressure roller's weight, preventing the pipe from being flattened. Once the pressure roller reaches the predetermined position, the operator returns the manual directional valve to the neutral position. As the pipe rotates centrifugally, the solenoid directional valve remains energized. The pressurized oil connected to the main inlet P forms a back pressure between the manual directional valve and the rodless chamber of the hydraulic cylinder through the other pressure reducing valve, the solenoid directional valve, and the check valve. This back pressure partially offsets the pressure exerted on the pipe by the pressure roller's weight, preventing the pipe from being flattened during radial runout. To prevent excessive radial runout during pipe rotation... The upward force generated will increase the pressure in the rod chamber in the reverse direction, thereby damaging the pipe. A control circuit is added to the rod chamber. The control circuit connects a hydraulically controlled check valve to the port of the rod chamber. The inlet of the hydraulically controlled check valve is connected to the main return port, and the outlet of the hydraulically controlled check valve is connected to the outlet of the pressure reducing valve connected to port A of the manual directional valve. The manual directional valve and the hydraulically controlled check valve are connected in parallel to the port of the rod chamber. The control end of the hydraulically controlled check valve is also connected to a solenoid valve. When the pressure measuring device detects the set pressure limit, it sends a signal to briefly energize the solenoid valve, opening the hydraulically controlled check valve to release the pressure in the rod chamber, thereby reducing the pressure of the pressure roller hydraulic cylinder on the pipe.

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