阅读说明：本技术 一种油缸压榨机液压系统漏油检测方法 (Oil leakage detection method for hydraulic system of oil cylinder squeezer ) 是由 纪智荣 胡军驰 赵敏洁 于 2019-10-25 设计创作，主要内容包括：本发明公开了一种油缸压榨机液压系统漏油检测方法。它包括：在蓄能器充压过程中,PLC检测设在小油缸与蓄能器之间的压力变送器的值；计数压力从0上升到设定值所用的时间为T,在无漏油情况下时间T为标准值；当所用时间超过T时,PLC自动控制停机并报漏油故障；在进泥过程中,PLC通过定时抽样检测压力变送器的值,计算两次检测值之差,设定一个标准差值；工作时当检测差值超过标准差值时,PLC自动控制停机并报漏油故障；在间歇压榨过程中,PLC通过检测压榨停止时和压榨开始时压力变送器的值,设定一个标准差值；工作时当检测值超过标准差值时,PLC自动控制停机并报漏油故障。该方法能及时发现小油缸漏油问题,减少液压油浪费。(The invention discloses an oil leakage detection method for a hydraulic system of an oil cylinder squeezer. It includes: in the process of pressurizing the energy accumulator, the PLC detects the value of a pressure transmitter arranged between the small oil cylinder and the energy accumulator; the time for the counting pressure to rise from 0 to a set value is T, and the time T is a standard value under the condition of no oil leakage; when the used time exceeds T, the PLC automatically controls the shutdown and reports the oil leakage fault; in the mud feeding process, the PLC detects the value of the pressure transmitter by timing sampling, calculates the difference between two detection values and sets a standard difference value; when the detection difference value exceeds the standard difference value during working, the PLC automatically controls the shutdown and reports the oil leakage fault; in the intermittent squeezing process, the PLC sets a standard difference value by detecting the values of the pressure transmitters when squeezing is stopped and when squeezing is started; when the detection value exceeds the standard difference value during working, the PLC automatically controls the shutdown and reports the oil leakage fault. The method can find the oil leakage problem of the small oil cylinder in time and reduce the waste of hydraulic oil.)

1. The oil leakage detection method for the hydraulic system of the oil cylinder squeezer is characterized by comprising the following steps of: the method comprises the following steps of (1) a pressure charging process, a mud feeding process and an intermittent squeezing process of an energy accumulator;

(1) and the accumulator charging process: in the process of pressurizing the energy accumulator, detecting the value of a pressure transmitter arranged between the small oil cylinder and the energy accumulator through a PLC (programmable logic controller); the time for the counting pressure of the pressure transmitter to rise from 0 to a set value is T, and the time T is a standard value under the condition of no oil leakage; when the time for the counting pressure of the pressure transmitter to rise from 0 to a set value exceeds a standard value T, the leakage of the small oil cylinder and the accessories is judged, the PLC controller controls the squeezer to automatically stop, and oil leakage faults of the small oil cylinder and the accessories are reported;

(2) and a mud feeding process: in the mud feeding process, the PLC detects the value of a pressure transmitter arranged between the small oil cylinder and the energy accumulator by sampling at regular time, calculates the difference between two detection values and sets a standard difference value; when the automatic oil leakage monitoring device works, when the difference between two detection values obtained by timing sampling detection exceeds the standard difference value, the small oil cylinder and the accessory are judged to have leakage, the PLC controller controls the squeezer to automatically stop, and oil leakage faults of the small oil cylinder and the accessory are reported;

(3) and an intermittent squeezing process: in the intermittent squeezing process, the PLC controller sets a standard difference value by detecting the values of pressure transmitters arranged between the small oil cylinder and the energy accumulator when squeezing is stopped and when squeezing is started; when the detection value exceeds the standard difference value during working, the leakage of the small oil cylinder and the accessories is judged, the PLC controller controls the squeezer to automatically stop, and the oil leakage fault of the small oil cylinder and the accessories is reported.

2. The oil leakage detection method for the hydraulic system of the oil cylinder squeezer according to claim 1, wherein the hydraulic system of the oil cylinder squeezer comprises an oil tank, a low-pressure pump, a high-pressure pump, a small oil cylinder, a large oil cylinder, a first reversing valve, a second reversing valve, an overflow valve, an accumulator and a pressure transmitter; the piston rods of the small oil cylinder and the large oil cylinder are positioned on the same axis, and when the piston rod of the large oil cylinder is positioned between the initial position and the mud inlet locking position, the piston rods of the small oil cylinder and the large oil cylinder are not in contact; when the piston rod of the large oil cylinder is pushed to a position between the mud locking position and the pressing end position, the small oil cylinder is in contact with the piston rod of the large oil cylinder; the low-pressure pump and the high-pressure pump are connected with the oil tank; the outlet of the low-pressure pump is connected with the outlet of the high-pressure pump; the outlet of the low-pressure pump and the outlet of the high-pressure pump are divided into two paths, one path is connected with the small oil cylinder through a first reversing valve, and the other path is connected with the rod cavity of the large oil cylinder through a second reversing valve; an overflow bypass connected with the oil tank is arranged on an oil pipeline connecting the small oil cylinder, the low-pressure pump and the high-pressure pump, an energy accumulator and an overflow valve are arranged on the overflow bypass, the energy accumulator is arranged in front of the overflow valve, and the outlet of the overflow valve is connected with the oil tank; a pressure transmitter is arranged between the small oil cylinder and the energy accumulator; a rodless cavity of the large oil cylinder is connected with the oil tank through a second reversing valve; the hydraulic system of the oil cylinder squeezer also comprises a PLC controller; the input end of the PLC is connected with a pressure transmitter arranged between the small oil cylinder and the energy accumulator; the output end of the PLC is connected with a motor of the high-pressure pump; and (3) when the small oil cylinder and the accessories are judged to have leakage in the processes (1), (2) and (3), the PLC controller controls the motor of the high-pressure pump to stop rotating.

3. The oil leakage detection method for the hydraulic system of the oil cylinder press as recited in claim 1 or 2, wherein the first reversing valve is a three-position four-way electromagnetic reversing valve having P, T, A, B four through ports.

4. The method for detecting oil leakage of hydraulic system of cylinder press according to claim 3, wherein the P inlet of the first directional control valve is connected to the outlet of the high pressure pump, the a outlet thereof is connected to the small cylinder, the B inlet thereof is connected to the small cylinder, and the T outlet thereof is connected to the oil tank.

5. The oil leakage detection method for the hydraulic system of the oil cylinder press as recited in claim 1 or 2, wherein the second reversing valve is a three-position four-way electromagnetic reversing valve having P, T, A, B four through ports.

6. The oil leakage detection method for the hydraulic system of the oil cylinder press according to claim 5, characterized in that the P inlet of the second reversing valve is connected with the outlet of the high pressure pump, and the A outlet of the second reversing valve is connected with the rod chamber of the large oil cylinder.

7. The method for detecting oil leakage of hydraulic system of cylinder press according to claim 6, wherein the B inlet of the second direction valve is connected to the rodless chamber of the large cylinder, and the T outlet of the second direction valve is connected to the oil tank.

Technical Field

The invention belongs to the technical field of sludge dewatering, and relates to a method for detecting oil leakage of a hydraulic system of an oil cylinder squeezer.

Background

The ultrahigh pressure elastic squeezer for sludge dewatering has two types, one is a spring squeezer and the other is an oil cylinder squeezer. The hydraulic system of the oil cylinder squeezer is relatively complex, and adopts a high-pressure and low-pressure double-pump system, as shown in fig. 1, the hydraulic system of the oil cylinder squeezer comprises an oil tank, a low-pressure pump 1, a high-pressure pump 2, a first reversing valve 3, a second reversing valve 4, an overflow valve 5, an energy accumulator 6, a small oil cylinder 7 and a large oil cylinder 8; the hydraulic working principle is as follows: in the starting state, the large cylinder 8 piston rod is in a retracted state (in the starting position a); when the machine starts to work, namely low-pressure fast forward, double pumps of a low-pressure pump 1 and a high-pressure pump 2 are used for supplying oil, and the high-pressure pump 2 is responsible for supplying oil to a small sealed oil cylinder 7 and supplying oil to a large oil cylinder 8 for slow squeezing; in the squeezing process, the high-pressure pump 2 supplies oil to the large oil cylinder 8 for squeezing, the small oil cylinder 7 is compressed by the large oil cylinder 8, oil of the small oil cylinder 7 returns to the oil tank through the overflow valve 5, and the overflow valve 5 keeps the sealing pressure of the small oil cylinder 7; when the piston rod of the large oil cylinder 8 extends to a squeezing end position C, the squeezing process is ended; a bypass with an overflow valve 5 and an energy accumulator 6 is arranged on an oil pipeline connected with the small oil cylinder 7 and the outlets of the low-pressure pump 1 and the high-pressure pump 2; the bypass with the overflow valve 5 and the accumulator 6 is connected with the oil tank; when the pressure of the small oil cylinder 7 is lower than a set value, the large oil cylinder 8 stops, the high-pressure pump 2 charges the energy accumulator 6, when the pressure of the energy accumulator 6 reaches the set pressure, the large oil cylinder 8 retreats again, and the small oil cylinder 7 extends out for a certain distance by depending on the oil pressure provided by the energy accumulator 6; when the pressure of the accumulator 6 is reduced to a set value, the large oil cylinder 8 must be stopped again, and the high-pressure pump 2 is enabled to charge the accumulator 6 again; the first reversing valve 3 and the second reversing valve 4 are used for controlling the pressurization and the pressure relief of the small oil cylinder 7 and the forward and backward movement of the large oil cylinder 8.

At present, the sealing pressure that superhigh pressure elasticity hydro-cylinder squeezer advances mud is produced thrust by little hydro-cylinder 7 and is realized, in operation because the back and forth movement of little hydro-cylinder 7, the sealing member of little hydro-cylinder 7 can wear and tear, produce the oil leak, because little hydro-cylinder 7 oil leak is difficult to observe, often will be sensed by liquid level relay when the hydraulic tank oil level arrives lower extreme position and just can signal or observe the oil level table, could discover and make the squeezer stop, hydraulic oil has lost a lot at this moment, huge waste has been caused.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide the oil leakage detection method for the hydraulic system of the oil cylinder squeezer, which can find the oil leakage problem of the small oil cylinder in time and reduce the waste of hydraulic oil.

The purpose of the invention is realized by the following technical scheme:

the invention discloses an oil leakage detection method for a hydraulic system of an oil cylinder squeezer, which comprises the following steps:

the whole working process of the hydraulic system of the oil cylinder squeezer is divided into: the method comprises the following steps of (1) a pressure charging process, a mud feeding process and an intermittent squeezing process of an energy accumulator;

(1) and the accumulator charging process: in the process of pressurizing the energy accumulator, detecting the value of a pressure transmitter arranged between the small oil cylinder and the energy accumulator through a PLC (programmable logic controller); the time for the counting pressure of the pressure transmitter to rise from 0 to a set value is T, and the time T is a standard value under the condition of no oil leakage; when the time for the counting pressure of the pressure transmitter to rise from 0 to a set value exceeds a standard value T, the leakage of the small oil cylinder and the accessories is judged, the PLC controller controls the squeezer to automatically stop, and oil leakage faults of the small oil cylinder and the accessories are reported.

(2) And a mud feeding process: in the mud feeding process, the PLC detects the value of a pressure transmitter arranged between the small oil cylinder and the energy accumulator by sampling at regular time, calculates the difference between two detection values and sets a standard difference value; when the automatic oil leakage alarm device works, when the difference between two detection values obtained by timing sampling detection exceeds the standard difference value, the leakage of the small oil cylinder and the accessory is judged, the PLC controller controls the squeezer to automatically stop, and the oil leakage fault of the small oil cylinder and the accessory is reported.

(3) And an intermittent squeezing process: in the intermittent squeezing process, the PLC controller sets a standard difference value by detecting the values of pressure transmitters arranged between the small oil cylinder and the energy accumulator when squeezing is stopped and when squeezing is started; when the detection value exceeds the standard difference value during working, the leakage of the small oil cylinder and the accessories is judged, the PLC controller controls the squeezer to automatically stop, and the oil leakage fault of the small oil cylinder and the accessories is reported.

Further, the hydraulic system of the oil cylinder squeezer comprises an oil tank, a low-pressure pump, a high-pressure pump, a small oil cylinder, a large oil cylinder, a first reversing valve, a second reversing valve, an overflow valve, an energy accumulator and a pressure transmitter; the piston rods of the small oil cylinder and the large oil cylinder are positioned on the same axis, and when the piston rod of the large oil cylinder is positioned between the initial position and the mud inlet locking position, the piston rods of the small oil cylinder and the large oil cylinder are not in contact; when the piston rod of the large oil cylinder is pushed to a position between the mud locking position and the pressing end position, the small oil cylinder is in contact with the piston rod of the large oil cylinder; the low-pressure pump and the high-pressure pump are connected with the oil tank; the outlet of the low-pressure pump is connected with the outlet of the high-pressure pump; the outlet of the low-pressure pump and the outlet of the high-pressure pump are divided into two paths, one path is connected with the small oil cylinder through a first reversing valve, and the other path is connected with the rod cavity of the large oil cylinder through a second reversing valve; an overflow bypass connected with the oil tank is arranged on an oil pipeline connecting the small oil cylinder, the low-pressure pump and the high-pressure pump, an energy accumulator and an overflow valve are arranged on the overflow bypass, the energy accumulator is arranged in front of the overflow valve, and the outlet of the overflow valve is connected with the oil tank; a pressure transmitter is arranged between the small oil cylinder and the energy accumulator; a rodless cavity of the large oil cylinder is connected with the oil tank through a second reversing valve; the hydraulic system of the oil cylinder squeezer also comprises a PLC controller; the input end of the PLC is connected with a pressure transmitter arranged between the small oil cylinder and the energy accumulator; the output end of the PLC is connected with a motor of the high-pressure pump; and (3) when the small oil cylinder and the accessories are judged to have leakage in the processes (1), (2) and (3), the PLC controller controls the motor of the high-pressure pump to stop rotating.

Furthermore, the first reversing valve is a three-position four-way electromagnetic reversing valve which is provided with P, T, A, B four through ports.

Furthermore, the P inlet of the first reversing valve is connected with the outlet of the high-pressure pump, the A outlet of the first reversing valve is connected with the small oil cylinder, the B inlet of the first reversing valve is connected with the small oil cylinder, and the T outlet of the first reversing valve is connected with the oil tank.

Furthermore, the second reversing valve is a three-position four-way electromagnetic reversing valve which is provided with P, T, A, B four through ports.

Furthermore, the P inlet of the second reversing valve is connected with the outlet of the high-pressure pump, and the A outlet of the second reversing valve is connected with the rod cavity of the large oil cylinder.

Furthermore, an inlet B of the second reversing valve is connected with the rodless cavity of the large oil cylinder, and an outlet T of the second reversing valve is connected with the oil tank.

The invention has the beneficial effects that:

the oil leakage detection method for the hydraulic system of the oil cylinder squeezer can conveniently and timely find and solve the problem of oil leakage of the small oil cylinder, when the small oil cylinder and accessories have oil leakage, the control system can timely give an alarm and stop working, so that maintenance personnel can timely maintain and prevent hydraulic oil from being wasted, and the purpose of preventing oil leakage can be achieved even if the oil cylinder squeezer is unattended.

According to the oil leakage detection method for the hydraulic system of the oil cylinder squeezer, the PLC is used for detecting the oil leakage condition of the small oil cylinder in the working process of the hydraulic system of the oil cylinder squeezer, so that the oil leakage problem of the small oil cylinder can be found in time, and the waste of hydraulic oil is reduced.

Drawings

Fig. 1 is a hydraulic schematic diagram of a hydraulic system of a cylinder press.

In the figure: 1. a low pressure pump; 2. a high pressure pump; 3. a first change valve (three-position four-way electromagnetic change valve); 4. a second directional valve (three-position four-way electromagnetic directional valve); 5. an overflow valve; 6. an accumulator; 7. a small oil cylinder; 8. a large oil cylinder; 9. a pressure transmitter; A. a starting position; B. locking a mud inlet position; C. pressing to the final position.

Detailed Description

The invention is further described below with reference to the following figures and examples.