Oil injection and exhaust method and device for hydraulic mechanism

Abstract

The invention discloses a hydraulic mechanism oil injection and exhaust method and device, and relates to the technical field of hydraulic mechanism oil-gas separation. The method comprises the steps that in response to an exhaust demand signal, a preset exhaust flow rate is obtained based on the correlation between gas solubility and the flow rate; and oil gas extraction in the oil pump and oil gas release in the exhaust space are executed according to the preset exhaust flow speed and the oil pump parameters, and when the stop condition is met, oil gas extraction is stopped, and oil injection and exhaust are executed. The oil-gas separation device has the beneficial effects that excessive separation structures are not needed, the overall space requirement is small, and the oil-gas separation requirements of the oil pump under different conditions are met.

Description

Technical Field

[0001] The present application relates to the technical field of oil-gas separation of hydraulic mechanisms, and in particular to a method and device for oil injection and exhaust of hydraulic mechanisms. Background Art

[0002] When the oil pump is running at high speed, the air dissolved in the hydraulic oil is precipitated due to the pressure reduction and mechanical stirring, forming tiny bubbles suspended in the oil. These bubbles usually float to the top of the oil pump and are discharged through the exhaust device. However, when the oil and gas are mixed too thoroughly or the oil flow state is complex, some tiny bubbles cannot be effectively gathered and discharged due to their small size, slow floating speed or high oil viscosity. Once the volume ratio of these bubbles in the oil exceeds the critical value, the bulk modulus of the oil will be significantly reduced, resulting in cavitation in the oil suction chamber of the oil pump, which in turn causes problems such as insufficient oil suction, output flow fluctuations, or even complete failure and idling of the oil pump.

[0003] In related technologies, the principle of low specific gravity of gas is used to make the bubbles naturally gathered at the top of the oil pump float up to the exhaust device through the connecting pipe. However, if the hydraulic oil and air are fully mixed, the gas can no longer gather in the exhaust device due to the influence of the viscosity of the hydraulic oil, resulting in the oil pump being unable to reliably pressurize.

[0004] The patent application "A Separation Device for Oil-Gas Mixture", publication number: CN112774259A, publication date: May 11, 2021, specifically discloses a separation tank, to which are respectively connected an oil inlet pipe, an oil drain pipe, an exhaust pipe, a safety valve and a water-liquid pipe, a nozzle is installed at one end of the liquid inlet pipe extending into the interior of the separation tank, an oil dispersion cap is provided below the nozzle, and a separation umbrella assembly is provided above the nozzle, an oil inlet pipe is fixed to the inner wall of the separation tank, and the bottom end of the oil inlet pipe extends to 5-10 cm above the water at the bottom of the inner cavity of the separation tank. This solution achieves the separation of the oil-gas mixture through the separation umbrella, the oil dispersion cap, etc., but its structure is complex and the space required is large, which is not suitable for oil-gas separation in hydraulic mechanism oil pumps. Summary of the Invention

[0005] This application addresses the problems in the prior art of oil pumps that oil-gas separation has poor separation effect and requires too much space for oil-gas separation. A method and device for oil filling and exhausting of a hydraulic mechanism is provided. By adaptively adjusting the flow rate of extracting hydraulic oil and releasing hydraulic oil to the exhaust space based on the principle of reduced gas solubility at high flow rates, the gas dissolved in the hydraulic oil is precipitated. At the same time, there is no need for excessive separation structures, and the overall space requirement is small, which is suitable for the oil-gas separation needs of oil pumps in different situations.

[0006] In order to achieve the above-mentioned technical objectives, a technical solution provided in the present application is a method for oil injection and exhaust of a hydraulic mechanism, comprising the following steps: in response to an exhaust demand signal, obtaining a preset exhaust flow rate based on the correlation between gas solubility and flow rate, performing oil and gas extraction in the oil pump and oil and gas release in the exhaust space according to the preset exhaust flow rate and oil pump parameters, and when the preset time is reached, stopping oil and gas extraction and performing oil injection and exhaust.

[0007] Furthermore, obtaining the preset exhaust flow rate based on the correlation between gas solubility and flow rate includes: obtaining the current ambient temperature, hydraulic oil parameters and gas parameters, and using the correlation between gas solubility and flow rate to obtain the preset exhaust flow rate according to the current ambient temperature, hydraulic oil parameters and gas parameters.

[0008] Furthermore, the extraction of oil and gas from the oil pump and the release of oil and gas in the exhaust space according to the preset exhaust flow rate and oil pump parameters include: calculating the oil and gas extraction speed and oil and gas extraction time of the oil extraction pipeline according to the oil pump parameters; and calculating the opening of the flow control valve according to the oil and gas extraction speed and the preset exhaust flow rate.

[0009] Furthermore, when the stop condition is met, stopping the oil and gas extraction and performing the oil injection and exhaust includes: when the oil and gas extraction time is met, pausing the oil and gas extraction and performing the oil injection and exhaust; if the oil pump electrical parameters after the oil injection and exhaust meet the oil pump electrical parameter threshold, stopping the oil and gas extraction; if the oil pump electrical parameters after the oil injection and exhaust do not meet the oil pump electrical parameter threshold, repeating the oil and gas extraction and oil injection and exhaust.

[0010] Furthermore, when the stop condition is met, stopping the oil and gas extraction and performing the oil injection and exhaust also includes: repeating the oil and gas extraction and the oil injection and exhaust within a preset time sequence; starting the oil pump after reaching the preset time sequence, and determining whether to terminate the oil and gas extraction based on the current oil pump electrical parameters and the oil pump electrical parameter threshold.

[0011] Furthermore, it also includes: obtaining the number of repeated executions, and determining whether to output an abnormal alarm based on the number of repeated executions and a preset repetition threshold.

[0012] Another technical solution provided by the present application is that the hydraulic mechanism oil filling and exhaust device is connected to the oil pump, includes an exhaust space, and is used to implement the above method, and also includes: a separation part, used to extract the oil and gas in the oil pump and release them into the exhaust space according to a preset exhaust flow rate; an exhaust part, used to discharge the gas in the exhaust space; and an oil return part, used to inject the exhausted hydraulic oil into the oil pump.

[0013] Furthermore, the separation part at least includes an oil extraction pipeline and a flow control valve, the oil extraction pipeline is connected to the exhaust space and the oil pump, and the flow control valve is arranged in the area where the oil extraction pipeline is located in the exhaust space.

[0014] Furthermore, the exhaust portion at least includes a vent valve arranged at the top of the exhaust space.

[0015] Furthermore, the oil return portion at least includes an oil return pipe and an oil return valve. The oil return pipe is connected to the exhaust space and the oil pump, and the oil return valve is arranged on the oil return pipe.

[0016] The beneficial effects of the present application are as follows: the gas dissolved in the hydraulic oil is precipitated through the oil and gas extraction speed and the oil and gas injection speed according to the relationship between the gas solubility and the flow rate, thereby ensuring the purity of the hydraulic oil in the oil pump, avoiding the problem of oil pump failure and idling due to excessive bubbles in the hydraulic oil, and ensuring the stable operation of the hydraulic mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of the oil filling and exhaust method for the hydraulic mechanism of this application.

[0018] Figure 2 This is a structural diagram of the oil filling and exhaust device of the hydraulic mechanism of this application. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of this application more clear, the application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific implementation method described here is only an optimal embodiment of this application, which is only used to explain this application and does not limit the scope of protection of this application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0020] like Figure 1 As shown in the first embodiment of the present application, the method for injecting oil and exhausting air from a hydraulic mechanism includes the following steps: In response to the exhaust demand signal, the preset exhaust flow rate is obtained based on the correlation between gas solubility and flow rate. According to the preset exhaust flow rate and oil pump parameters, oil and gas extraction in the oil pump and oil and gas release in the exhaust space are performed. When the stop condition is met, the oil and gas extraction is stopped and oil injection and exhaust are performed.

[0021] In this embodiment, the gas dissolved in the hydraulic oil is precipitated through the oil and gas extraction speed and the oil and gas injection speed according to the relationship between the gas solubility and the flow rate, thereby ensuring the purity of the hydraulic oil in the oil pump, avoiding the problem of oil pump failure and idling due to excessive bubbles in the hydraulic oil, and ensuring the stable operation of the hydraulic mechanism. There is no need for excessive separation structures, the overall space requirement is small, and it is adapted to the oil and gas separation needs of the oil pump in different situations.

[0022] Specifically, obtaining the preset exhaust flow rate based on the correlation between gas solubility and flow rate includes: The current ambient temperature, hydraulic oil parameters and gas parameters are obtained, and the preset exhaust flow rate is obtained according to the current ambient temperature, hydraulic oil parameters and gas parameters using the correlation between gas solubility and flow rate.

[0023] Temperature, the properties of the hydraulic oil, and the type of gas will all affect the solubility of the gas in the hydraulic oil, and an excessively high flow rate will destroy the equilibrium pressure of the hydraulic oil, thereby affecting the solubility of the gas in the hydraulic oil. Therefore, a correlation between gas solubility and flow rate is established based on temperature, hydraulic oil parameters, gas parameters, and flow rate. During the exhaust process, the flow rate at which the gas solubility changes under current conditions is first retrieved based on the current ambient temperature, hydraulic oil parameters, and gas parameters. This is used as the preset exhaust flow rate, and then the hydraulic oil, oil-gas mixture, or / and gas in the oil pump are extracted and released based on the preset exhaust flow rate. The high flow rate destroys the equilibrium pressure of the oil-gas mixture, reduces the contact area between the liquid phase and the gas phase, reduces the gas solubility, and causes the gas to precipitate, thereby achieving oil-gas separation in the oil-gas mixture and avoiding the problem of oil pump idling caused by excessive tiny bubbles in the hydraulic oil.

[0024] In this embodiment, hydraulic oil parameters include at least hydraulic oil composition, hydraulic oil viscosity, and polarity, and gas parameters include at least gas type. Principal component analysis, neural network learning algorithms, and the like can be used to analyze the effects of temperature, hydraulic oil parameters, and gas parameters on solubility, identifying turning points for solubility under different conditions. The flow rate corresponding to the turning point is then used as the preset exhaust flow rate for the corresponding temperature, hydraulic oil parameters, and gas parameters. Of course, in other cases, the preset exhaust flow rate can be directly set based on expert experience. For example, when the gas is nitrogen, the preset exhaust flow rate is 2 m / s.

[0025] Extracting oil and gas from the pump and releasing oil and gas from the exhaust space according to the preset exhaust flow rate and pump parameters include: Calculate the oil and gas extraction speed and time of the oil extraction pipeline according to the oil pump parameters; The opening of the flow control valve is calculated based on the oil and gas extraction rate and the preset exhaust flow rate.

[0026] The oil pump parameters include at least the parameters of the oil extraction pipeline and the oil pump capacity. The oil extraction pipeline parameters include at least the shape, material, and diameter of the oil extraction pipeline. The volume of oil and gas to be extracted is calculated based on the oil pump capacity, and the pressure bearing capacity of the oil extraction pipeline is calculated based on the shape, material, and diameter of the oil extraction pipeline. The maximum flow rate of the oil extraction pipeline is calculated based on the pressure bearing capacity of the oil extraction pipeline. If the maximum flow rate of the oil extraction pipeline is less than the preset exhaust flow rate, the maximum flow rate of the oil extraction pipeline is used as the oil and gas extraction speed. If the maximum flow rate of the oil extraction pipeline is greater than or equal to the preset exhaust flow rate, the preset exhaust flow rate is used as the oil and gas extraction speed. The oil and gas extraction time is calculated based on the oil and gas extraction speed and the oil and gas volume. When the oil and gas extraction speed is different from the preset exhaust flow rate, the opening of the flow control valve at the oil and gas release port is calculated based on the difference between the oil and gas extraction speed and the preset exhaust flow rate. The opening of the flow control valve is used to achieve the difference in flow rate between the oil and gas release port and the pipeline, thereby ensuring the stability of the pipeline and achieving high-flow separation of oil and gas.

[0027] In other cases, because the oil pump and exhaust device are typically connected using rubber hoses, replacing the flow control valve is more difficult than replacing the rubber hose. In this case, the oil and gas extraction rate is calculated based on the correlation between pressure and oil extraction pipeline wear, the correlation between pressure and flow control valve wear, and the minimum replacement cost. The maximum acceptable flow rate is used to establish constraints, and the optimal oil and gas extraction rate for the current situation is calculated to avoid excessive pressure on the flow control valve. Of course, pipeline loss can also be included in the constraints, and the current maximum acceptable flow rate can be updated in real time based on pipeline loss to further ensure the stability and safety of oil injection and exhaust.

[0028] In this embodiment, oil and gas extraction is to extract the oil and gas mixture, gas, and oil at the top of the oil pump into the exhaust space, and oil and gas release is to separate the oil and gas by injection when the oil and gas are extracted into the exhaust space.

[0029] Among them, the stop condition includes at least the oil and gas extraction time. When the oil and gas extraction time is reached, the oil and gas extraction is stopped, and negative pressure exhaust is performed to remove the gas in the exhaust space, and the hydraulic oil with the gas removed is injected back into the oil pump, so that the hydraulic oil content in the oil pump remains stable, ensuring the reliability of the hydraulic mechanism.

[0030] In other cases, the stop condition includes at least the oil and gas extraction time and the oil pump electrical parameter threshold. In this case, when the stop condition is met, stopping the oil and gas extraction and performing oil filling and exhaust includes: When the oil and gas extraction time is met, the oil and gas extraction is suspended and oil injection and exhaust are performed; If the oil pump electrical parameters after oil injection and exhaust meet the oil pump electrical parameter threshold, the oil and gas extraction is terminated. If the oil pump electrical parameters after oil injection and exhaust do not meet the oil pump electrical parameter threshold, the oil and gas extraction and oil injection and exhaust are repeated.

[0031] In this case, when the oil and gas extraction time is reached, the oil and gas extraction is first suspended, and oil injection and exhaust are performed once to obtain the current oil pump electrical parameters and compare the current oil pump electrical parameters with the oil pump electrical parameter threshold. If the current oil pump electrical parameters meet the oil pump electrical parameter threshold requirements, the oil and gas extraction is terminated. If the current oil pump electrical parameters do not meet the oil pump electrical parameter threshold requirements, the oil and gas extraction and oil injection and exhaust are repeated until the oil pump electrical parameters after exhaust meet the oil pump electrical parameter threshold requirements, thereby ensuring that the oil pump always maintains a reliable pressurization state and avoiding the influence of tiny bubbles in the hydraulic oil on the pressurization.

[0032] In some cases, when there is too much gas in the hydraulic oil, exhausting once cannot meet the exhaust demand, and pumping the oil pump after each exhaust will increase unnecessary loss of the oil pump. Therefore, when the stop condition is met, stopping oil and gas extraction and performing oil filling and exhausting also includes: Repeatedly perform oil and gas extraction and oil filling and exhaust within the preset time sequence; After the preset timing is reached, the oil pump is started, and whether to terminate oil and gas extraction is determined based on the current oil pump electrical parameters and the oil pump electrical parameter threshold.

[0033] The oil pump electrical parameter includes the oil pump current, and the oil pump electrical parameter threshold includes the oil pump current threshold. Accordingly, the exhaust demand signal in this embodiment can be generated by a human input signal or automatically output based on the oil pump electrical parameter threshold. For example, an exhaust demand signal is output when the oil pump electrical parameter falls below the oil pump electrical parameter threshold.

[0034] In this embodiment, the preset timing is 1 minute, and the cycle is executed within 1 minute: the oil and gas at the top of the oil pump are extracted into the exhaust space and sprayed according to the preset exhaust flow rate, and the gas in the hydraulic oil is precipitated with the help of the flow rate. There is an oil return pipe in the exhaust space, and the exhausted hydraulic oil is injected back into the oil pump through the oil return pipe.

[0035] The hydraulic mechanism oil injection and exhaust method further includes: Get the number of repeated executions and determine whether to output an abnormal alarm based on the number of repeated executions and the preset repetition threshold.

[0036] The number of repetitions of oil and gas extraction and oil filling and exhaust is recorded. If the preset repetition threshold is reached but the oil pump electrical parameter threshold is still not met, the oil pump is considered abnormal and an abnormality alarm is issued. In this embodiment, the preset repetition threshold is 5. It is understood that the number of repetitions can be calculated based on the number of oil and gas extraction and oil filling and exhaust executions throughout the entire process, or simply the number of times the oil pump is started can be calculated.

[0037] As the second embodiment of this application, Figure 2 As shown, the motor is connected to the oil pump, the oil pump is connected to the hydraulic mechanism, the hydraulic mechanism is connected to the low-pressure oil tank, and the hydraulic mechanism oil filling and exhaust device is connected to the oil pump to perform oil and gas separation on the hydraulic oil in the oil pump. At this time, the hydraulic mechanism oil filling and exhaust device, connected to the oil pump, includes: exhaust space; A separation part, used to extract the oil and gas in the oil pump and release them into the exhaust space according to a preset exhaust flow rate; An exhaust portion, used to discharge the gas in the exhaust space; The oil return part is used to inject the exhausted hydraulic oil into the oil pump.

[0038] In this embodiment, the separation portion and the oil return portion are connected to the oil pump. During the oil injection and exhaust process, the separation portion and the oil return portion have different conduction conditions.

[0039] Specifically, the separation unit includes at least an oil extraction pipeline and a flow control valve. The oil extraction pipeline is connected to the exhaust space and the oil pump, and the flow control valve is located in the area of ​​the oil extraction pipeline located in the exhaust space. It is understood that the separation unit also includes an oil extraction pump, such as a vacuum pump or a self-priming pump, to extract oil and gas from the oil pump.

[0040] In this embodiment, the oil extraction pipeline includes an external pipeline and an internal pipeline. The external pipeline is the pipeline connecting the hydraulic mechanism oil filling and exhaust device and the oil pump, and the internal pipeline is the pipeline inside the exhaust space. The flow control valve is arranged in the internal pipeline, and the external pipeline and the internal pipeline are made of different materials. The external pipeline is more flexible and convenient for pipeline laying, and the internal pipeline is more rigid and can withstand higher impact, meeting the pressure requirements of high flow rate.

[0041] The exhaust part at least includes a vent valve and a vacuum pump arranged at the top of the exhaust space, and the gas in the exhaust space is exhausted by the negative pressure exhaust of the vacuum pump.

[0042] The oil return part includes at least an oil return pipe and an oil return valve. The oil return pipe is connected to the exhaust space and the oil pump. The oil return valve is arranged on the oil return pipe. The return of hydraulic oil is achieved by opening and closing the oil return valve.

[0043] The specific implementation described above is a preferred implementation of the hydraulic mechanism oil injection and exhaust method and device of this application, and is not intended to limit the specific implementation scope of this application. The scope of this application includes but is not limited to this specific implementation. Any equivalent changes made in accordance with the shape and structure of this application are within the scope of protection of this application.

Claims

1. A method for oil filling and exhausting a hydraulic mechanism, characterized by: The steps include: In response to the exhaust demand signal, the preset exhaust flow rate is obtained based on the correlation between gas solubility and flow rate. According to the preset exhaust flow rate and oil pump parameters, oil and gas extraction in the oil pump and oil and gas release in the exhaust space are performed. When the preset time is reached, the oil and gas extraction is stopped and oil injection and exhaust are performed.

2. The method for oil filling and exhausting a hydraulic mechanism according to claim 1, wherein: The step of obtaining a preset exhaust flow rate based on the correlation between gas solubility and flow rate includes: The current ambient temperature, hydraulic oil parameters and gas parameters are obtained, and the preset exhaust flow rate is obtained according to the current ambient temperature, hydraulic oil parameters and gas parameters using the correlation between gas solubility and flow rate.

3. The method for oil filling and exhausting a hydraulic mechanism according to claim 1, wherein: The extracting of oil and gas from the oil pump and releasing of oil and gas from the exhaust space according to the preset exhaust flow rate and oil pump parameters includes: Calculate the oil and gas extraction speed and time of the oil extraction pipeline according to the oil pump parameters; The opening of the flow control valve is calculated based on the oil and gas extraction rate and the preset exhaust flow rate.

4. The method for oil filling and exhausting a hydraulic mechanism according to claim 3, wherein: When the stop condition is met, stopping the oil and gas extraction and performing oil filling and exhaust includes: When the oil and gas extraction time is met, the oil and gas extraction is suspended and oil injection and exhaust are performed; If the oil pump electrical parameters after oil filling and exhaust meet the oil pump electrical parameter threshold, oil and gas extraction is stopped; if the oil pump electrical parameters after oil filling and exhaust do not meet the oil pump electrical parameter threshold, oil and gas extraction and oil filling and exhaust are repeated.

5. The method for oil filling and exhausting a hydraulic mechanism according to claim 3, wherein: When the stop condition is met, stopping the oil and gas extraction and performing oil filling and exhaust further includes: Repeatedly perform oil and gas extraction and oil filling and exhaust within the preset time sequence; After the preset timing is reached, the oil pump is started, and whether to terminate oil and gas extraction is determined based on the current oil pump electrical parameters and the oil pump electrical parameter threshold.

6. The method for oil filling and exhausting a hydraulic mechanism according to claim 1, wherein: Also includes: Get the number of repeated executions and determine whether to output an abnormal alarm based on the number of repeated executions and the preset repetition threshold.

7. A hydraulic mechanism oil filling and exhaust device, connected to an oil pump, comprising an exhaust space, for implementing the method according to any one of claims 1 to 6, characterized in that: Also includes: A separation part, used to extract the oil and gas in the oil pump and release them into the exhaust space according to a preset exhaust flow rate; An exhaust portion, used to discharge the gas in the exhaust space; The oil return part is used to inject the exhausted hydraulic oil into the oil pump.

8. The oil filling and exhaust device for a hydraulic mechanism according to claim 7, characterized in that: The separation part at least includes an oil extraction pipeline and a flow control valve. The oil extraction pipeline is connected to the exhaust space and the oil pump. The flow control valve is arranged in the area where the oil extraction pipeline is located in the exhaust space.

9. The oil filling and exhaust device for a hydraulic mechanism according to claim 7, characterized in that: The exhaust portion at least includes a vent valve arranged at the top of the exhaust space.

10. The oil filling and exhaust device for a hydraulic mechanism according to claim 7, characterized in that: The oil return portion at least includes an oil return pipeline and an oil return valve. The oil return pipeline is connected to the exhaust space and the oil pump, and the oil return valve is arranged on the oil return pipeline.

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