Device and method for improving operation stability of hydraulic system

Abstract

The invention discloses a device for improving operation stability of a hydraulic system, which relates to the technical field of rolling equipment and comprises an oil tank, a first circulating pump, a first plate heat exchanger, a second plate heat exchanger, a heat exchanger switching device, a water activity detection device, a second circulating pump and an oil-water separator. The inlet end of the first circulating pump is connected with the outlet end of the oil tank, the outlet end of the first circulating pump is connected with the inlet end of the heat exchanger switching device, and the outlet end of the heat exchanger switching device is connected with the inlet ends of the first plate heat exchanger and the second plate heat exchanger. The outlet ends of the first plate heat exchanger and the second plate heat exchanger are connected with the inlet end of the oil tank. The double-plate heat exchanger is additionally arranged, the water activity detector, the automatic switching device and the oil-water separator are combined, when water enters the oil liquid at the initial stage, the plate heat exchanger is automatically switched, the oil-water separator is automatically started for water separation and filtration, the oil liquid emulsification phenomenon is avoided, and the operation stability of the rolling mill servo hydraulic system is indirectly improved.

Description

Technical Field

[0001] This invention relates to the field of rolling equipment technology, and in particular to a device and method for improving the operational stability of a hydraulic system. Background Technology

[0002] Currently, high-frequency electro-hydraulic proportional servo control systems are widely used in rolling mill hydraulic systems. The hydraulic system circulation device uses plate heat exchangers for heat exchange. During use, plate heat exchangers often break down, and water from heat exchange seeps into the oil, causing emulsification of the hydraulic oil. This is especially problematic for electro-hydraulic proportional servo control systems. Once oil emulsification occurs, it will cause abnormal operation of the proportional and servo valves, resulting in unplanned rolling and, in severe cases, major equipment failures. After oil emulsification, it is necessary to shut down the machine to clean the oil tank and replace the oil, which takes about 20 hours and seriously affects the production schedule. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a device and method for improving the operational stability of a hydraulic system.

[0004] To solve the above technical problems, the technical solution of the present invention is as follows: An apparatus for improving the operational stability of a hydraulic system includes: an oil tank, a first circulating pump, a first plate heat exchanger, a second plate heat exchanger, a heat exchanger switching device, a water activity detection device, a second circulating pump, and an oil-water separator. The inlet end of the first circulating pump is connected to the outlet end of the oil tank, the outlet end of the first circulating pump is connected to the inlet end of the heat exchanger switching device, the outlet end of the heat exchanger switching device is connected to the inlet ends of the first plate heat exchanger and the second plate heat exchanger respectively, and the outlet ends of the first plate heat exchanger and the second plate heat exchanger are both connected to the inlet end of the oil tank. The water activity detection device is connected to the connecting pipeline between the first circulating pump and the heat exchanger switching device; The inlet end of the second circulating pump is connected to the outlet end of the oil tank, the outlet end of the second circulating pump is connected to the inlet end of the oil-water separator, and the outlet end of the oil-water separator is connected to the inlet end of the oil tank.

[0005] As a preferred embodiment of the device for improving the operational stability of a hydraulic system according to the present invention, the heat exchanger switching device includes a three-way switching valve, the three-way switching valve including a valve body, a switching valve core rotatably disposed in the valve body, and a first locking sleeve and a second locking sleeve fixedly connected to both sides of the valve body. When the switching valve core rotates to the first angle range, the channel in the first locking sleeve is in the open state, and the channel in the second locking sleeve is in the closed state; When the switching valve core rotates to the second angle range, the channel in the second locking sleeve is in the open state, and the channel in the first locking sleeve is in the closed state; When the switching valve core rotates to the third angle range, the channels in the first locking sleeve and the second locking sleeve are both in a closed state.

[0006] As a preferred embodiment of the device for improving the operational stability of a hydraulic system according to the present invention, a sealing ring is provided between the valve body and the first locking sleeve and between the valve body and the second locking sleeve.

[0007] As a preferred embodiment of the device for improving the operational stability of a hydraulic system according to the present invention, wherein: a pre-tensioning spring is provided in both the first locking sleeve and the second locking sleeve, one end of the pre-tensioning spring abuts against the locking sleeve, and the other end of the pre-tensioning spring abuts against the adjacent sealing ring; When the sealing ring is in close contact with the valve body, the preload spring is in a compressed state.

[0008] As a preferred embodiment of the device for improving the operational stability of a hydraulic system according to the present invention, wherein: a buffer valve plate is inserted into both the first locking sleeve and the second locking sleeve, the axis of the buffer valve plate coincides with the axis of the locking sleeve, and a plurality of through holes are uniformly opened on the buffer valve plate.

[0009] As a preferred embodiment of the device for improving the operational stability of a hydraulic system according to the present invention, an electric butterfly valve is provided in both the first locking sleeve and the second locking sleeve connected to the inlet ends of the first plate heat exchanger and the second plate heat exchanger.

[0010] As a preferred embodiment of the device for improving the operational stability of a hydraulic system according to the present invention, the switching valve core is provided with a pressure equalization hole.

[0011] The present invention also provides a method for improving the operational stability of a hydraulic system, which is based on the above-described apparatus for improving the operational stability of a hydraulic system, comprising: The first circulation pump draws oil from the oil tank and transports it along the oil pipeline to the heat exchanger switching device. The water activity index in the oil is detected by a water activity detector, and it is determined whether it is within the threshold range. If it is, the system operates normally; otherwise, the next step is executed. The circuits of the first plate heat exchanger and the second plate heat exchanger are switched by the heat exchanger switching device, so that the oil inlet pipe, oil outlet pipe, water inlet pipe and water outlet pipe of the first plate heat exchanger are closed, and the oil inlet pipe, oil outlet pipe, water inlet pipe and water outlet pipe of the second plate heat exchanger are opened. Control the operation of the second circulation pump to transport the oil in the oil tank to the oil-water separator until the water activity index in the oil is within the threshold range.

[0012] The beneficial effects of this invention are: (1) The present invention adds a double plate heat exchanger, combined with a water activity detector, an automatic switching device, and an oil-water separator. When water enters the oil in the initial stage, the plate heat exchanger is automatically switched and the oil-water separator is automatically turned on to separate and filter water, so as to avoid the oil from emulsifying and indirectly improve the operation stability of the rolling mill servo hydraulic system.

[0013] (2) The three-way switching valve provided by the present invention has simple results and reliable switching. It can be used in pairs or multiple groups to meet the requirements of simultaneous opening and closing of multiple channels.

[0014] (3) In this invention, sealing rings are provided between the valve body and the first locking sleeve, and between the valve body and the second locking sleeve. The sealing rings ensure the sealing between the valve body and the two locking sleeves. At the same time, preload springs are installed in both the first and second locking sleeves. During use, the locking sleeves and the valve body apply pressure to both ends of the preload springs, keeping the preload springs in a compressed state, thereby ensuring that the sealing rings are always tightly attached to the valve core, preventing the sealing rings of the three-way switching valve from loosening and creating gaps during use.

[0015] (4) The present invention has pressure equalization holes on the switching valve core. During use, the oil circuit or water circuit closed end will have the same medium and pressure oil passing through, so that the plate heat exchanger always has a small amount of medium passing through, eliminating the pressure difference between the two ends, reducing the impact when the three-way switching valve is switched, thereby extending the service life of the plate heat exchanger. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of the device for improving the operational stability of a hydraulic system provided by the present invention; Figure 2 A schematic diagram of the three-way switching valve in the device for improving the operational stability of a hydraulic system provided by the present invention; Figure 3 An exploded view of the three-way switching valve in the device for improving the operational stability of a hydraulic system provided by the present invention; Figure 4 This is the front view of the buffer valve plate; Figure 5 This is a schematic diagram showing the connection between the three-way switching valve and the first and second plate heat exchangers. The components include: 1. Oil tank; 2. First circulating pump; 3. Water activity detection device; 4. Heat exchanger switching device; 5. First plate heat exchanger; 6. Second plate heat exchanger; 7. Oil-water separator; 8. Second circulating pump; 9. First locking sleeve; 10. Valve body; 11. Sealing ring; 12. Second locking sleeve; 13. Buffer valve plate; 14. Preload spring; 15. Switching valve core; 16. Electric butterfly valve; 17. Telescopic rod. Detailed Implementation

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] Figure 1 This is a schematic diagram of a device for improving the operational stability of a hydraulic system, provided in an embodiment of this application. The device includes an oil tank, a first circulating pump, a first plate heat exchanger, a second plate heat exchanger, a heat exchanger switching device, a water activity detection device, and an oil-water separator. Specifically, when the first plate heat exchanger leaks, causing the water activity index of the oil in the tank to exceed the standard, the heat exchanger switching device can shut down the first plate heat exchanger and switch to operation of the second plate heat exchanger, and then the water in the oil is removed by the oil-water separator.

[0020] For details, see Figure 1 The inlet of the first circulating pump is connected to the outlet of the oil tank. The outlet of the first circulating pump is connected to the inlet of the heat exchanger switching device. The outlet of the heat exchanger switching device is connected to the inlets of both the first and second plate heat exchangers. The outlets of both the first and second plate heat exchangers are connected to the inlet of the oil tank. A water activity detection device is connected to the connecting pipeline between the first circulating pump and the heat exchanger switching device. The inlet of the second circulating pump is connected to the outlet of the oil tank. The outlet of the second circulating pump is connected to the inlet of the oil-water separator. The outlet of the oil-water separator is connected to the inlet of the oil tank.

[0021] The aforementioned heat exchanger switching device includes a three-way switching valve. (See also...) Figure 2 The three-way switching valve includes a valve body, a switching valve core rotatably installed in the valve body, and a first locking sleeve and a second locking sleeve fixedly installed on both sides of the valve body.

[0022] Specifically, when the switching valve core rotates to the first angle range, the channel in the first locking sleeve is in the open state, and the channel in the second locking sleeve is in the closed state; when the switching valve core rotates to the second angle range, the channel in the second locking sleeve is in the open state, and the channel in the first locking sleeve is in the closed state; when the switching valve core rotates to the third angle range, the channels in both the first and second locking sleeves are in the closed state.

[0023] Preferably, sealing rings are provided between the valve body and the first locking sleeve, and between the valve body and the second locking sleeve. These sealing rings ensure a tight seal between the valve body and the two locking sleeves. Simultaneously, preload springs are installed within both the first and second locking sleeves. One end of the preload spring abuts against the inside of the locking sleeve, and the other end abuts against the adjacent sealing ring. Because the sealing ring is in contact with the valve body, during use, the locking sleeve and the valve body apply pressure to both ends of the preload spring, keeping it in a compressed state. This ensures that the sealing ring remains tightly against the valve core, preventing loosening and gaps during use of the three-way switching valve's sealing ring.

[0024] To reduce instantaneous fluctuations in oil pressure in the circulating system and water pressure in the external environment, and to minimize impact, cartridge-type buffer valve plates are installed in both the first and second locking sleeves. The axis of the buffer valve plate coincides with the axis of the locking sleeve in which it is located. See also Figure 4 The buffer valve plate is a multi-hole spring valve plate, that is, several through holes are evenly opened on the buffer valve plate. When the system oil pressure or water pressure is too high, the impact force will push the spring valve plate open to offset the impact force, so as to avoid the impact force acting directly on the heat exchanger plate and extend the service life of the plate heat exchanger.

[0025] See Figure 5 The three-way switching valve is a dual-head switching valve, which can rotate both upwards and downwards. The intermediate switching point, along with a central telescopic adjusting rod, allows the three-way switching valve to be used as a modular unit, in single, double, or multiple configurations. The length of the central telescopic rod can be extended and locked according to site conditions.

[0026] It should be noted that the inlet and outlet water, oil inlet and outlet oil lines of the first plate heat exchanger and the newly added second plate heat exchanger are combined in pairs using three-way switching valves to form a double group. The inlet and outlet water lines each use a separate set of three-way switching valves to form a water circuit control loop. That is, the main inlet water loop is split into two paths to the plate heat exchangers via an automatic switching valve: one path enters from the first plate heat exchanger, and the other from the second plate heat exchanger. During operation, one of these inlet water paths is open while the other is closed. After passing through the two plate heat exchangers, the inlet water flows out from the return water inlet via a three-way switching valve and then converges at the outlet. During operation, one of these return water paths is open while the other is closed. Similarly, the synchronous oil inlet and outlet water lines also use a set of three-way switching valves to form an oil circuit control loop, operating on the same principle as the water circuit.

[0027] To mitigate switching shock and extend the service life of the plate heat exchanger, a pressure equalization hole is provided on the switching valve core. During operation, the closed ends of the oil or water circuit will each have the same medium and pressure oil passing through, ensuring that a small amount of medium always flows through the plate heat exchanger, eliminating the pressure difference between the two ends and reducing the shock when the three-way switching valve is switched.

[0028] This application also provides a method for improving the operational stability of a hydraulic system, based on the aforementioned device for improving the operational stability of a hydraulic system. The method specifically includes the following steps: Step S101: The first circulation pump draws oil from the oil tank and transports it along the oil pipeline to the heat exchanger switching device; Step S102: Detect the water activity index in the oil using a water activity detector and determine whether it is within the threshold range. If yes, then operate normally; otherwise, proceed to the next step. Step S103: Switch the circuits of the first plate heat exchanger and the second plate heat exchanger by means of the heat exchanger switching device, so that the oil inlet pipe, oil outlet pipe, water inlet pipe and water outlet pipe of the first plate heat exchanger are closed, and the oil inlet pipe, oil outlet pipe, water inlet pipe and water outlet pipe of the second plate heat exchanger are opened. Step S104: Control the second circulation pump to transport the oil in the oil tank to the oil-water separator until the water activity index in the oil is within the threshold range.

[0029] Therefore, the technical solution of this application adds a double plate heat exchanger, combined with a water activity detector, an automatic switching device, and an oil-water separator. When water is initially introduced into the oil, the plate heat exchanger is automatically switched and the oil-water separator is automatically turned on to separate and filter water, so as to avoid emulsification of the oil and indirectly improve the operational stability of the rolling mill servo hydraulic system.

[0030] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A device for improving the operational stability of a hydraulic system, characterized in that: include: Oil tank, first circulating pump, first plate heat exchanger, second plate heat exchanger, heat exchanger switching device, water activity detection device, second circulating pump and oil-water separator; The inlet end of the first circulating pump is connected to the outlet end of the oil tank, the outlet end of the first circulating pump is connected to the inlet end of the heat exchanger switching device, the outlet end of the heat exchanger switching device is connected to the inlet ends of the first plate heat exchanger and the second plate heat exchanger respectively, and the outlet ends of the first plate heat exchanger and the second plate heat exchanger are both connected to the inlet end of the oil tank. The water activity detection device is connected to the connecting pipeline between the first circulating pump and the heat exchanger switching device; The inlet end of the second circulating pump is connected to the outlet end of the oil tank, the outlet end of the second circulating pump is connected to the inlet end of the oil-water separator, and the outlet end of the oil-water separator is connected to the inlet end of the oil tank.

2. The device for improving the operational stability of a hydraulic system according to claim 1, characterized in that: The heat exchanger switching device includes a three-way switching valve, which includes a valve body, a switching valve core rotatably disposed within the valve body, and a first locking sleeve and a second locking sleeve fixedly connected to both sides of the valve body. When the switching valve core rotates to the first angle range, the channel in the first locking sleeve is in the open state, and the channel in the second locking sleeve is in the closed state; When the switching valve core rotates to the second angle range, the channel in the second locking sleeve is in the open state, and the channel in the first locking sleeve is in the closed state; When the switching valve core rotates to the third angle range, the channels in the first locking sleeve and the second locking sleeve are both in a closed state.

3. The device for improving the operational stability of a hydraulic system according to claim 2, characterized in that: A sealing ring is provided between the valve body and the first locking sleeve, and between the valve body and the second locking sleeve.

4. The device for improving the operational stability of a hydraulic system according to claim 3, characterized in that: Both the first locking sleeve and the second locking sleeve are provided with a pre-tightening spring. One end of the pre-tightening spring abuts against the inside of the locking sleeve, and the other end of the pre-tightening spring abuts against the adjacent sealing ring. When the sealing ring is in close contact with the valve body, the preload spring is in a compressed state.

5. The device for improving the operational stability of a hydraulic system according to claim 2, characterized in that: Both the first locking sleeve and the second locking sleeve have a buffer valve plate inserted inside. The axis of the buffer valve plate coincides with the axis of the locking sleeve. The buffer valve plate has several through holes evenly distributed on it.

6. The device for improving the operational stability of a hydraulic system according to claim 2, characterized in that: Electric butterfly valves are installed in both the first locking sleeve and the second locking sleeve, which are connected to the inlet ends of the first plate heat exchanger and the second plate heat exchanger.

7. The device for improving the operational stability of a hydraulic system according to claim 2, characterized in that: The switching valve core is provided with pressure equalization holes.

8. A method for improving the operational stability of a hydraulic system, based on the aforementioned device for improving the operational stability of a hydraulic system, characterized in that: include: The first circulation pump draws oil from the oil tank and transports it along the oil pipeline to the heat exchanger switching device. The water activity index in the oil is detected by a water activity detector, and it is determined whether it is within the threshold range. If it is, the system operates normally; otherwise, the next step is executed. The circuits of the first plate heat exchanger and the second plate heat exchanger are switched by the heat exchanger switching device, so that the oil inlet pipe, oil outlet pipe, water inlet pipe and water outlet pipe of the first plate heat exchanger are closed, and the oil inlet pipe, oil outlet pipe, water inlet pipe and water outlet pipe of the second plate heat exchanger are opened. Control the operation of the second circulation pump to transport the oil in the oil tank to the oil-water separator until the water activity index in the oil is within the threshold range.

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