Furnace door lifting hydraulic control loop

Abstract

The utility model provides a furnace door lifting hydraulic control loop which comprises a hydraulic cylinder, a high-pressure oil source, a low-pressure oil source, an energy accumulator set, a proportional valve, a first one-way valve, a stop valve, a control valve, a second one-way valve, a third hydraulic control one-way valve, a fourth hydraulic control one-way valve and a fifth one-way valve. Under the action of the low-pressure oil source, the balance state between the rod cavity and the rodless cavity is broken, the pressure oil of the rod cavity is higher than the pressure of the energy accumulator set, the pressure oil flows back into the energy accumulator set, and energy recovery is formed. When the rodless cavity is communicated with the oil tank through the proportional valve, the hydraulic cylinder completes the retraction action under the action of pressure oil of the energy accumulator set, and energy is reused. According to the utility model, the lifting of the furnace door can be stably and accurately controlled, and the gravitational potential energy of the furnace door can be recycled. In addition, a conventional control mode can be switched conveniently, and stability and reliability of the loop are guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic control, in particular to a furnace door lifting hydraulic control circuit. Background Art

[0002] In many heavy lifting equipment driven by hydraulic control systems, the gravitational potential energy of the heavy objects and the lifting equipment itself can be recycled and reused to achieve energy-saving effects. For example, walking-beam heating furnaces, walking-beam transport chains, coil transport trolleys and other equipment in the steel and metallurgical field, the weight of the equipment itself and the heavy objects being lifted often ranges from tens of tons to thousands of tons. The potential energy recovery of heavy objects is crucial to the energy saving of the entire hydraulic system.

[0003] Metallurgical heating furnace is an important part of the large family of industrial furnaces. It includes several sub-types. The most common ones can be divided into roller bottom type, pusher type, ring type and walking type according to the different mechanical forms of the furnace bottom. Roller bottom heating furnace and pusher type heating furnace are relatively primitive products. Ring type heating furnace and walking type heating furnace are the mainstream products with relatively advanced technology. Among them, walking furnace is the most widely used furnace type at present. It is the main furnace type that replaces pusher furnace and roller bottom furnace. With its widespread popularization and promotion, roller bottom heating furnace and pusher type heating furnace will be gradually replaced by it; with the continuous improvement of the degree of automation of industrial production, in order to meet the new requirements of large-scale and high-precision steel rolling technology, the walking type heating furnace is developing in the direction of large-scale, energy-saving and environmental protection, pollution-free and automated production operation, so as to improve its production performance and promote the progress of the metallurgical industry.

[0004] In a walking beam heating furnace, the furnace door is mostly hydraulically driven to lift. Generally, the weight of the furnace door is 7-8 tons, and the rod chamber matched to the hydraulic cylinder is a relatively high pressure. However, this energy is not recovered during conventional control, and externally supplied high-pressure oil is required to control the hydraulic action of lifting the furnace door. The lifting action of the furnace door is relatively frequent, and each action not only cannot recover energy, but also requires a large amount of energy from the outside to complete the control, resulting in a large waste of energy. These energies will also cause other problems caused by the increase in the temperature of the hydraulic oil. Utility Model Content

[0005] In view of the above problems existing in the prior art, the technical problem to be solved by the utility model is: Under normal circumstances, the weight of the furnace door is 7-8 tons, and the rod chamber matched to the hydraulic cylinder is a relatively high pressure. However, the energy is not recovered during conventional control, and externally supplied high-pressure oil is required to control the hydraulic action of the furnace door lifting and lowering. The furnace door lifting and lowering actions are relatively frequent, and each action not only cannot recover energy, but also requires a large amount of energy to be provided externally to complete the control, resulting in a large waste of energy. These energies will also cause other problems caused by the increase in the temperature of the hydraulic oil.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions: a furnace door lifting hydraulic control circuit, including an energy-saving control structure, the energy-saving control structure includes: a hydraulic cylinder, a high-pressure oil source, a low-pressure oil source, an oil tank, an accumulator group, a proportional valve and a first check valve;

[0007] The T port of the proportional valve is connected to the oil tank; the B port of the proportional valve is connected to the rod chamber of the hydraulic cylinder through the first one-way valve; the A port of the proportional valve is connected to the rodless chamber of the hydraulic cylinder; the P port of the proportional valve is connected to the low-pressure oil source, so as to drive the piston rod of the hydraulic cylinder to extend through the low-pressure oil source under the control of the proportional valve;

[0008] The high-pressure oil source is connected to the rod chamber of the hydraulic cylinder, and the accumulator group is installed on the high-pressure oil source to recover the pressure oil in the rod chamber of the hydraulic cylinder through the accumulator group.

[0009] Preferably, a conventional control structure is also included, which includes: a cut-off valve, a first one-way valve combination, a second one-way valve combination and a control valve; the two ends of the cut-off valve are respectively connected to the low-pressure oil source and the high-pressure oil source; one end of the first one-way valve combination is installed on the oil circuit between the low-pressure oil source and the proportional valve, and is located between the cut-off valve and the proportional valve; the other end of the first one-way valve combination is connected to the rod chamber of the hydraulic cylinder; the first one-way valve combination is used to connect or disconnect the rod chamber of the hydraulic cylinder to the low-pressure oil source in one direction; the second one-way valve combination is installed on the oil circuit between the high-pressure oil source and the rod chamber of the hydraulic cylinder, and the second one-way valve combination is used to connect or disconnect the high-pressure oil source and the rod chamber of the hydraulic cylinder; the control valve is used to open the first one-way valve combination or the second one-way valve combination.

[0010] Preferably, the first one-way valve combination includes: a second one-way valve and a third hydraulically controlled one-way valve; one end of the second one-way valve and the third hydraulically controlled one-way valve are connected to each other, the other end of the second one-way valve is installed on the oil circuit between the low-pressure oil source and the proportional valve, and the other end of the third hydraulically controlled one-way valve is connected to the rod chamber of the hydraulic cylinder; the third hydraulically controlled one-way valve flows in a one-way direction toward the rod chamber of the hydraulic cylinder, and the second one-way valve and the third hydraulically controlled one-way valve have opposite flow directions; the control valve can control the third hydraulically controlled one-way valve to be in an open state.

[0011] Preferably, the second one-way valve combination includes two fourth hydraulically controlled one-way valves; the two fourth hydraulically controlled one-way valves are sequentially installed in the oil circuit between the high-pressure oil source and the rod chamber of the hydraulic cylinder; and the flow directions of the two fourth hydraulically controlled one-way valves are opposite; the control valve can control the two fourth hydraulically controlled one-way valves to be in an open state.

[0012] Preferably, it further comprises a fifth one-way valve, which is installed on the oil circuit between the cut-off valve and the low-pressure oil source, and the fifth one-way valve allows one-way flow of oil through the low-pressure oil source toward the cut-off valve.

[0013] Preferably, the pressure of the accumulator group and the high-pressure oil source is higher than the back pressure formed in the rod chamber of the hydraulic cylinder by the weight of the furnace door, and is lower than the back pressure formed in the rod chamber under the dual action of the low-pressure oil source and the gravity of the furnace door.

[0014] Preferably, the pressure of the high-pressure oil source is 2-4 times that of the low-pressure oil source.

[0015] Compared with the prior art, the utility model has at least the following advantages:

[0016] 1. In the utility model, when it is necessary to control the furnace door to descend, the P port and the A port of the control proportional valve are connected; the rodless chamber of the hydraulic cylinder is connected with the low-pressure oil source, the rodless chamber of the hydraulic cylinder is disconnected from the oil tank, and the low-pressure oil source supplies oil toward the rodless chamber of the hydraulic cylinder, and the low-pressure oil source applies a pressure P2 to the piston rod to push the piston rod of the hydraulic cylinder up; due to the area ratio of the rodless chamber and the rod chamber of the hydraulic cylinder, under the action of the low-pressure oil source, the pressure formed in the rod chamber is about 2P2; at this time, the total pressure of the sum of the pressure 2P2 in the rod chamber and the pressure P3 formed by the gravitational potential energy of the furnace door will be higher than the pressure P1 of the high-pressure oil source, breaking the balance between the rod chamber and the rodless chamber, and the pressure oil in the rod chamber flows back to the accumulator group to form energy recovery; for this reason, not only can the lifting and lowering of the furnace door be controlled stably and accurately, but also the gravitational potential energy of the furnace door can be recycled; the pressure oil stored in the accumulator group can be used for the next hydraulic cylinder retraction or other equipment.

[0017] 2. In the present invention, the energy-saving control mode and the conventional control mode can be switched according to the situation; by switching to the conventional control mode, the stability and reliability of the hydraulic circuit can be effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation of the utility model, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0019] Figure 1 A schematic diagram of a furnace door lifting hydraulic control circuit provided in an embodiment of the utility model.

[0020] Figure markings: 1-hydraulic cylinder, 2-high-pressure oil source, 3-low-pressure oil source, 4-oil tank, 5-accumulator group, 6-proportional valve, 7-first one-way valve, 8-cut-off valve, 9-control valve, 10-second one-way valve, 11-third hydraulically controlled one-way valve, 12-fourth hydraulically controlled one-way valve, 13-fifth one-way valve, 14-explosion-proof valve, 15-furnace door. DETAILED DESCRIPTION

[0021] The following embodiments of the technical solution of the utility model are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and are therefore only used as examples, and cannot be used to limit the protection scope of the utility model.

[0022] In the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] See also Figure 1 , the utility model provides an embodiment: a furnace door lifting hydraulic control circuit, including an energy-saving control structure, the energy-saving control structure includes: a hydraulic cylinder 1, a high-pressure oil source 2, a low-pressure oil source 3, an oil tank 4, an accumulator group 5, a proportional valve 6 and a first one-way valve 7; the T port of the proportional valve 6 is connected to the oil tank 4; the B port of the proportional valve 6 is connected to the rod chamber of the hydraulic cylinder 1 through the first one-way valve 7; the A port of the proportional valve 6 is connected to the rodless chamber of the hydraulic cylinder 1; the P port of the proportional valve 6 is connected to the low-pressure oil source 3, so as to drive the piston rod of the hydraulic cylinder 1 to extend through the low-pressure oil source 3 through the control of the proportional valve 6; the high-pressure oil source 2 is connected to the rod chamber of the hydraulic cylinder 1, and the accumulator group 5 is installed on the high-pressure oil source 2 to recover the pressure oil in the rod chamber of the hydraulic cylinder 1 through the accumulator group 5.

[0025] Furthermore, the pressure of the accumulator group 5 and the high-pressure oil source 2 is higher than the back pressure formed in the rod chamber of the hydraulic cylinder 1 by the weight of the furnace door 15, and is lower than the back pressure formed in the rod chamber by the dual action of the low-pressure oil source 2 and the gravity of the furnace door 15. The pressure of the high-pressure oil source is 2-4 times that of the low-pressure oil source.

[0026] During specific implementation, the hydraulic cylinder 1 is arranged upward to pull the furnace door 15 through the chain and the pulley; when the piston rod moves upward, the furnace door 15 is driven downward through the pulley and the pulley; conversely, when the piston rod moves downward, the furnace door 15 rises; the high-pressure oil source 2 applies a constant pressure P1, and the low-pressure oil source 3 applies a constant pressure P2.

[0027] To this end, when it is necessary to control the furnace door 15 to descend, the P port and the A port of the proportional valve 6 are connected; the rodless chamber of the hydraulic cylinder 1 is connected to the low-pressure oil source 3, and the B port of the proportional valve 6 is connected to the T port. Due to the action of the first one-way valve 7, the rodless chamber of the hydraulic cylinder 1 is disconnected from the oil tank 4, and the low-pressure oil source 3 supplies oil to the rodless chamber of the hydraulic cylinder 1. The low-pressure oil source 3 applies a pressure P2 to the piston rod, thereby pushing the piston rod of the hydraulic cylinder 1 to rise; due to the area ratio of the rodless chamber and the rod chamber of the hydraulic cylinder 1, under the action of the low-pressure oil source 3, a pressure of about 2P2 is formed in the rod chamber; at this time, in the rod chamber The total pressure of the sum of the pressure 2P2 and the pressure P3 formed by the gravitational potential energy of the furnace door 15 will be higher than the pressure P1 of the high-pressure oil source 2. Under the action of the low-pressure oil source 3, the equilibrium state between the rod chamber and the rodless chamber of the hydraulic cylinder 1 is broken, and the pressure oil in the rod chamber of the hydraulic cylinder 1 will be higher than the pressure of the accumulator group 5, pushing the piston rod upward; when the piston rod of the hydraulic cylinder 1 moves upward, the pressure oil in the rod chamber flows to the accumulator group 5; for this reason, the gravitational potential energy of the furnace door 15 can be recycled; the pressure oil stored in the accumulator group 5 can be used the next time the hydraulic cylinder 1 is retracted or used by other equipment.

[0028] When it is necessary to control the furnace door 15 to rise, the T port and the A port of the proportional valve 6 are controlled to be connected, so that the rodless chamber of the hydraulic cylinder 1 is disconnected from the low-pressure oil source 3, and the rodless chamber of the hydraulic cylinder 1 is connected to the oil tank 4, and the pressure oil in the rodless chamber of the hydraulic cylinder 1 flows back to the oil tank 4 through the A port and the T port of the proportional valve 6; because the pressure oil of the accumulator group 5 is greater than the load of the furnace door 15, the pressure oil of the high-pressure oil source 2 and the pressure oil in the accumulator group 5 enter the rod chamber of the hydraulic cylinder 1, pushing the piston rod of the hydraulic cylinder 1 to descend and retract; thereby driving the furnace door 15 to rise, so that the lifting and lowering of the furnace door 5 can be stably and accurately controlled.

[0029] See also Figure 1In other embodiments, a conventional control structure is also included, which includes: a cut-off valve 8, a first one-way valve combination, a second one-way valve combination and a control valve 9; the two ends of the cut-off valve 8 are respectively connected to the low-pressure oil source 3 and the high-pressure oil source 2; one end of the first one-way valve combination is installed on the oil circuit between the low-pressure oil source 3 and the proportional valve 6, and one end of the first one-way valve combination is located between the cut-off valve 8 and the proportional valve 6; the other end of the first one-way valve combination is connected to the rod chamber of the hydraulic cylinder 1; the first one-way valve combination is used to connect or disconnect the rod chamber of the hydraulic cylinder 1 to the low-pressure oil source 3 in one direction; the second one-way valve combination is installed on the oil circuit between the high-pressure oil source 2 and the rod chamber of the hydraulic cylinder 1, and the second one-way valve combination is used to connect or disconnect the high-pressure oil source 2 and the rod chamber of the hydraulic cylinder 1; the control valve 9 is used to open the first one-way valve combination or the second one-way valve combination.

[0030] In special circumstances, when it is necessary to switch to the conventional control mode, the cut-off valve 8 is controlled to open, so that the high-pressure oil source 2 is connected to the low-pressure oil source 3, and the second one-way valve combination is controlled to be closed by the control valve 9, so that the second one-way valve combination disconnects the high-pressure oil source 2 and the rod chamber of the hydraulic cylinder 1; and the control valve 9 controls the first one-way valve combination to open, so that the rod chamber of the hydraulic cylinder 1 is connected to the low-pressure oil source 3 in one direction; in this way, the conventional differential control mode can be switched, which is simple and reliable.

[0031] In the normal control mode, when it is necessary to control the furnace door 15 to descend, the P port and the A port of the control proportional valve 6 are connected, and the T port and the B port are connected, so that the pressure oil of the high-pressure oil source 2 flows to the P port of the proportional valve 6 through the cut-off valve 8, and then flows to the rodless chamber of the hydraulic valve through the A port of the proportional valve 6; at the same time, under the action of the rodless chamber of the hydraulic cylinder 1 and the gravity of the furnace door 15, the pressure oil in the rod chamber of the hydraulic cylinder 1 flows to the P port of the proportional valve 6 through the first one-way valve combination, and enters the rodless chamber of the hydraulic cylinder 1; thereby pushing the hydraulic cylinder 1 to rise, so that the furnace door 15 can be driven to descend under the action of the pulley and the pulley.

[0032] When it is necessary to control the furnace door 15 to rise, the P port of the proportional valve 6 is controlled to be connected to the B port, and the T port is connected to the A port; the pressure oil of the high-pressure oil source 2 flows to the P port of the proportional valve 6 through the cut-off valve 8, and then flows to the rod chamber of the hydraulic cylinder 1 through the B port of the proportional valve 6, pushing the piston rod to move downward, thereby driving the furnace door 15 to rise through the pulley and pulley; at the same time, the pressure oil in the rodless chamber of the hydraulic cylinder 1 flows back to the oil tank 4 through the A port and T port of the proportional valve 6.

[0033] See also Figure 1In other embodiments, the first one-way valve combination includes: a second one-way valve 10 and a third hydraulically controlled one-way valve 11; one end of the second one-way valve 10 and the third hydraulically controlled one-way valve 11 are connected to each other, the other end of the second one-way valve 10 is installed in the oil circuit between the low-pressure oil source 3 and the proportional valve 6, and the other end of the third hydraulically controlled one-way valve 11 is connected to the rod chamber of the hydraulic cylinder 1; the third hydraulically controlled one-way valve 11 flows in one direction toward the rod chamber of the hydraulic cylinder 1, and the second one-way valve 10 and the third hydraulically controlled one-way valve 11 flow in opposite directions; the control valve 9 can control the third hydraulically controlled one-way valve 11 to be in an open state. Specifically, when it is necessary to control the furnace door 15 to descend, the third hydraulically controlled one-way valve 11 is controlled to be in an open state by the control valve 9; under the action of the gravity of the rodless chamber of the hydraulic cylinder 1 and the furnace door 15, the pressure oil in the rod chamber of the hydraulic cylinder 1 flows to the P port of the proportional valve 6 through the third hydraulically controlled one-way valve 11 and the second one-way valve 10 in sequence.

[0034] See also Figure 1 In other embodiments, the second one-way valve combination includes two fourth hydraulically controlled one-way valves 12; the two fourth hydraulically controlled one-way valves 12 are sequentially installed on the oil circuit between the high-pressure oil source 2 and the rod chamber of the hydraulic cylinder 1; and the flow directions of the two fourth hydraulically controlled one-way valves 12 are opposite; the control valve 9 can control the two fourth hydraulically controlled one-way valves 12 to be in an open state. Specifically, when it is necessary to switch to the conventional control mode, the control valve 9 does not control the two fourth hydraulically controlled one-way valves 12, so that the two hydraulically controlled one-way valves disconnect the oil circuit between the high-pressure oil source 2 and the rod chamber of the hydraulic cylinder 1; when it is necessary to switch to the energy-saving control mode, the control valve 9 controls the two fourth hydraulically controlled one-way valves 12 to be in an open state, so that the high-pressure oil source 2 and the rod chamber of the hydraulic cylinder 1 are connected.

[0035] See also Figure 1 In other embodiments, a fifth one-way valve 13 is further included. The fifth one-way valve 13 is installed on the oil path between the cut-off valve 8 and the low-pressure oil source 3, and the fifth one-way valve 13 allows one-way flow through the low-pressure oil source 3 toward the cut-off valve 8. By setting the fifth one-way valve 13, when the cut-off valve 8 is opened, the pressure oil of the high-pressure oil source 2 will not flow into the low-pressure oil source 3.

[0036] See also Figure 1 In other embodiments, an explosion-proof valve 14 is further included, and the explosion-proof valve 14 is installed in the oil path of the rod chamber of the hydraulic cylinder 1. When the hydraulic cylinder 1 is not in motion, the pressure oil in the hydraulic cylinder 1 is locked by the explosion-proof valve 14 under the action of the gravity of the furnace door 15.

[0037] In other embodiments, the control valve 9 is a three-position four-way electromagnetic reversing valve, the P port of the control valve 9 is connected to the low-pressure oil source 3, the T port is connected to the oil discharge port T, the A port is connected to the control oil port of the third hydraulically controlled one-way valve 11, and the B port is connected to the control oil ports of the two fourth hydraulically controlled one-way valves 12. When the a side of the control valve 9 is energized, the P port of the control valve 9 is connected to the B port, and the T port is connected to the A port; when the b side of the control valve 9 is energized, the P port of the control valve 9 is connected to the A port, and the T port is connected to the B port.

[0038] In other embodiments, the proportional valve 6 is a three-position four-way electromagnetic reversing valve. When the a side of the proportional valve 6 is energized, the P port of the proportional valve 6 is connected to the B port, and the T port is connected to the A port; when the b side of the proportional valve 6 is energized, the P port of the control valve 9 is connected to the A port, and the T port is connected to the B port.

[0039] In another embodiment, the port A of the first check valve 7 is connected to the port B of the proportional valve 6, and the port B of the first check valve 7 is connected to the rod chamber of the hydraulic cylinder 1 through the explosion-proof valve 14; the port A of the second check valve 10 is connected to the port A of the third hydraulically controlled check valve 11, and the port B of the second check valve 10 is installed in the oil circuit between the low-pressure oil source 3 and the proportional valve 6, and the port B of the third hydraulically controlled check valve 11 is installed in the oil circuit between the explosion-proof valve 14 and the first check valve 7. The ports A of the two fourth hydraulically controlled check valves 12 are connected to each other, the port B of one of the fourth hydraulically controlled check valves 12 is connected to the rod chamber of the hydraulic cylinder 1 through the explosion-proof valve 14, and the port B of the other fourth hydraulically controlled check valve 12 is connected to the high-pressure oil source 2; the port A of the fifth check valve 13 is connected to the low-pressure oil source 3, and the port B of the fifth check valve 13 is connected to the port P of the proportional valve 6.

[0040] The working principle and use process of the utility model: the control oil circuit is divided into an energy-saving control mode and a conventional control mode.

[0041] When it is necessary to switch to the energy-saving control mode, the shut-off valve 8 is controlled to be closed.

[0042] In energy-saving control mode:

[0043] When the furnace door 15 needs to be controlled to rise, the a side of the proportional valve 6 is energized. Since the pressure oil of the accumulator group 5 is greater than the load of the furnace door 15, the pressure oil of the high-pressure oil source 2 and the pressure oil in the accumulator group 5 enter the two fourth hydraulic control check valves 12 in sequence, and then enter the rod chamber of the hydraulic cylinder 1, pushing the piston rod of the hydraulic cylinder 1 to descend and retract; thereby driving the furnace door 15 to rise. At the same time, the pressure oil in the rodless chamber of the hydraulic cylinder 1 flows into the oil tank 4 through the A port and the T port of the proportional valve 6 in sequence.

[0044] When the furnace door 15 needs to be lowered, the b side of the proportional valve 6 is controlled to be energized; the pressure oil in the low-pressure oil source 3 passes through the fifth one-way valve 13, and then passes through the P port and A port of the proportional valve 6 in turn, and then flows to the rodless chamber of the hydraulic cylinder 1; the low-pressure oil source 3 applies a pressure P2 to the piston rod to push the piston rod of the hydraulic cylinder 1 up; due to the area ratio of the rodless chamber and the rod chamber of the hydraulic cylinder 1, under the action of the low-pressure oil source 3, the pressure formed in the rod chamber is about 2P2; at this time, the total pressure of the sum of the pressure 2P2 in the rod chamber and the pressure P3 formed by the gravitational potential energy of the furnace door 15 will be higher than the pressure P1 of the high-pressure oil source 2, and when the piston rod of the hydraulic cylinder 1 moves upward, the pressure oil in the rod chamber passes through the two fourth hydraulically controlled one-way valves 12 in turn and flows into the accumulator group 5; for this reason, the gravitational potential energy of the furnace door 15 can be recycled; the pressure oil stored in the accumulator group 5 can be used the next time the hydraulic cylinder 1 is retracted or used by other equipment.

[0045] When it is necessary to switch to the normal control mode, the cut-off valve 8 is controlled to open, so that the high-pressure oil source 2 is connected to the low-pressure oil source 3; then the a side of the control valve 9 is controlled to be energized, and the pressure oil flows from the P port of the control valve 9 to the A port, and then enters the control oil port of the third hydraulically controlled one-way valve 11, so as to complete the control of the third hydraulically controlled one-way valve 11, so that the third hydraulically controlled one-way valve 11 is in an open state. In this way, the switching of the normal control mode can be completed.

[0046] In normal control mode:

[0047] When it is necessary to control the furnace door 15 to rise, the b side of the control proportional valve 6 is energized, so that the pressure oil of the high-pressure oil source 2 flows to the P port of the proportional valve 6 through the cut-off valve 8, and then flows to the rod chamber of the hydraulic cylinder 1 through the B port of the proportional valve 6, pushing the piston rod to move downward, thereby driving the furnace door 15 to rise through the pulley and pulley; at the same time, the pressure oil in the rodless chamber of the hydraulic cylinder 1 flows back to the oil tank 4 through the A port and T port of the proportional valve 6.

[0048] When it is necessary to control the furnace door 15 to descend, the a side of the proportional valve 6 is energized, so that the pressure oil of the high-pressure oil source 2 flows to the P port of the proportional valve 6 through the cut-off valve 8, and then flows to the rodless chamber of the hydraulic valve through the A port of the proportional valve 6; at the same time, under the action of the rodless chamber of the hydraulic cylinder 1 and the gravity of the furnace door 15, and under the restriction of the first one-way valve 7, the pressure oil in the rod chamber of the hydraulic cylinder 1 will only pass through the third hydraulically controlled one-way valve 11 and the second one-way valve 10 in sequence, and then flow to the P port of the proportional valve 6 and enter the rodless chamber of the hydraulic cylinder 1; thereby pushing the hydraulic cylinder 1 to rise, and thus being able to drive the furnace door 15 to descend under the action of the pulley and the pulley.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A furnace door lifting hydraulic control circuit, characterized in that: It includes an energy-saving control structure, which includes: a hydraulic cylinder, a high-pressure oil source, a low-pressure oil source, an oil tank, an accumulator group, a proportional valve and a first one-way valve; The T port of the proportional valve is connected to the oil tank; the B port of the proportional valve is connected to the rod chamber of the hydraulic cylinder through the first one-way valve; the A port of the proportional valve is connected to the rodless chamber of the hydraulic cylinder; the P port of the proportional valve is connected to the low-pressure oil source, so as to drive the piston rod of the hydraulic cylinder to extend through the low-pressure oil source under the control of the proportional valve; The high-pressure oil source is connected to the rod chamber of the hydraulic cylinder, and the accumulator group is installed on the high-pressure oil source to recover the pressure oil in the rod chamber of the hydraulic cylinder through the accumulator group.

2. A furnace door lifting hydraulic control circuit according to claim 1, characterized in that: It also includes a conventional control structure, which includes: a cut-off valve, a first one-way valve combination, a second one-way valve combination and a control valve; the two ends of the cut-off valve are respectively connected to the low-pressure oil source and the high-pressure oil source; one end of the first one-way valve combination is installed on the oil circuit between the low-pressure oil source and the proportional valve, and is located between the cut-off valve and the proportional valve; the other end of the first one-way valve combination is connected to the rod chamber of the hydraulic cylinder; the first one-way valve combination is used to connect or disconnect the rod chamber of the hydraulic cylinder to the low-pressure oil source in one direction; the second one-way valve combination is installed on the oil circuit between the high-pressure oil source and the rod chamber of the hydraulic cylinder, and the second one-way valve combination is used to connect or disconnect the high-pressure oil source and the rod chamber of the hydraulic cylinder; the control valve is used to open the first one-way valve combination or the second one-way valve combination.

3. A furnace door lifting hydraulic control circuit according to claim 2, characterized in that: The first one-way valve combination includes: a second one-way valve and a third hydraulically controlled one-way valve; one end of the second one-way valve and the third hydraulically controlled one-way valve are connected to each other, the other end of the second one-way valve is installed in the oil circuit between the low-pressure oil source and the proportional valve, and the other end of the third hydraulically controlled one-way valve is connected to the rod chamber of the hydraulic cylinder; the third hydraulically controlled one-way valve flows in a one-way direction toward the rod chamber of the hydraulic cylinder, and the second one-way valve and the third hydraulically controlled one-way valve have opposite flow directions; the control valve can control the third hydraulically controlled one-way valve to be in an open state.

4. A furnace door lifting hydraulic control circuit according to claim 2, characterized in that: The second one-way valve combination includes two fourth hydraulically controlled one-way valves; the two fourth hydraulically controlled one-way valves are installed in sequence on the oil circuit between the high-pressure oil source and the rod chamber of the hydraulic cylinder; and the flow directions of the two fourth hydraulically controlled one-way valves are opposite; the control valve can control the two fourth hydraulically controlled one-way valves to be in an open state.

5. A furnace door lifting hydraulic control circuit according to claim 2, characterized in that: It also includes a fifth one-way valve, which is installed on the oil path between the cut-off valve and the low-pressure oil source, and the fifth one-way valve allows the low-pressure oil source to flow in one direction toward the cut-off valve.

6. A furnace door lifting hydraulic control circuit according to claim 1, characterized in that: The pressure of the accumulator group and the high-pressure oil source is higher than the back pressure formed in the rod chamber of the hydraulic cylinder by the weight of the furnace door, and is lower than the back pressure formed in the rod chamber by the dual action of the low-pressure oil source and the gravity of the furnace door.

7. The furnace door lifting hydraulic control circuit according to claim 1, characterized in that: The pressure of the high-pressure oil source is 2-4 times that of the low-pressure oil source.

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