Pump switching control system for lubrication without shutdown of thin oil station

Abstract

According to the pump switching control system for lubrication without shutdown of the thin oil station, the de-noising circuit receives a 4-20mA pressure signal of the pressure sensor detection system, the 4-20mA pressure signal is converted into a voltage signal through impedance, common-mode interference is suppressed through the differential-mode capacitor and the common-mode capacitor, the voltage signal enters the operational amplifier AR1 to be subjected to differential amplification, second-order active filtering is carried out through the Sialjeva circuit, and the voltage signal is converted into the voltage signal. Finally, 0-5V voltage is output through two-way amplitude limiting and one-way conduction, enters a threshold comparison circuit and is subjected to hysteresis comparison with a set value, stable high and low levels are output and enter a steady-state trigger circuit, and then charging, two-way diode conduction and rapid trigger triode conduction control are carried out, so that disturbance is reduced, and stability is improved; the change rate of the denoised pressure signal is calculated through the change rate calculation circuit, time integration of the integral compensation circuit is achieved, the denoised pressure signal is compensated in an inverse time limit mode, pressure signal prediction is achieved, and switching can be controlled in time.

Description

Technical Field

[0001] The utility model relates to the technical field of a thin oil station and a pump switching control, in particular to a pump switching control system for a thin oil station without stopping lubrication. Background Art

[0002] Prior art: A control system for a dilute oil station with application number 201620844546.X. The remote control unit has added a three-phase air switch QF3, and the local control unit has added a knob switch QS3. Whether it is remote control or local control, the operator only needs to add the same operating steps to start the standby pump without stopping the working pump and then switch the working mode. This switching process will not cause the lubrication system dilute oil station to stop operating, thereby ensuring the safe and stable operation of the mechanical equipment.

[0003] The specific start-up control of the three-phase air switch QF3 / knob switch QS3 detects the system pressure through the pressure sensor. When the pressure is lower than the set value, it is remotely automatically controlled or manually controlled. On the one hand, the operation of the equipment affects the accuracy of pressure detection. On the other hand, the point value comparison between the pressure and the set value has poor stability, and the pressure change rate is not calculated and then predicted, which will also cause the problem of untimely switching. Summary of the invention

[0004] In view of the deficiencies in the prior art, the utility model aims to provide a pump switching control system for lubrication of a thin oil station without stopping operation, which effectively solves the problems in the prior art.

[0005] The technical solution is to include an oil tank, an oil pump, a one-way valve, a double-cylinder mesh oil filter, and a shell-and-tube oil cooler. The oil is sucked out from the oil tank by the oil pump, and is directly sent to the equipment for lubrication through the one-way valve, the double-cylinder mesh oil filter, and the shell-and-tube oil cooler. The oil pump is characterized in that the oil pump includes a working pump and a standby pump, and is provided with a pressure sensor, a denoising circuit, a threshold comparison circuit, a steady-state trigger circuit, a rate of change calculation circuit, and an integral compensation circuit. The pressure sensor is connected to the denoising circuit, the denoising circuit is connected to the threshold comparison circuit and the rate of change calculation circuit, the threshold comparison circuit is connected to the steady-state trigger circuit, the steady-state trigger circuit switches the working pump and the standby pump, the rate of change calculation circuit is connected to the integral compensation circuit, and the integral compensation circuit is connected to the threshold comparison circuit.

[0006] Preferably, the denoising circuit includes a capacitor C1, a resistor R1, a resistor R2, and a resistor R4. The upper end of the capacitor C1, the upper end of the resistor R2, and the left end of the resistor R1 are respectively connected to the + signal output by the pressure sensor, the lower end of the capacitor C1, the lower end of the resistor R2, and the left end of the resistor R4 are respectively connected to the - signal output by the pressure sensor, the other end of the resistor R1 is respectively connected to one end of the resistor R3 and one end of the capacitor C5, the other end of the resistor R3 is respectively connected to one end of the grounded capacitor C3, one end of the capacitor C2, and the non-inverting input end of the operational amplifier AR1, the other end of the resistor R4 is respectively connected to one end of the grounded capacitor C4, the other end of the capacitor C2, the inverting input end of the operational amplifier AR1, and one end of the resistor R5, the output end of the operational amplifier AR1 is respectively connected to the other end of the capacitor C5, the other end of the resistor R5, the positive electrode of the diode D1, the negative electrode of the diode D2, and the positive electrode of the diode D3, the negative electrode of the diode D1 is connected to the power supply +5V0, the positive electrode of the diode D2 is connected to the ground, and the negative electrode of the diode D3 is the denoising circuit output signal. The steady-state trigger circuit includes a resistor R12, one end of which is connected to the output end of the operational amplifier AR2, the other end of which is respectively connected to one end of the grounding capacitor C10 and the left end of the bidirectional diode SD1, the right end of the bidirectional diode SD1 is respectively connected to the cathode of the diode D5 and one end of the resistor R13, the anode of the diode D5 is connected to the ground, the other end of the resistor R13 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is connected to the ground, the collector of the transistor Q1 is connected to one end of the normally closed contact K1-4 of the relay K1, the other end of the normally closed contact K1-4 of the relay K1 is respectively connected to one end of the relay K1 coil and the anode of the diode D6, the other end of the relay K1 coil and the cathode of the diode D6 are connected to the power supply +5V0, and the break contact K1-3 of the relay K1 switches the working pump and the standby pump.

[0007] Preferably, the change rate calculation circuit includes a capacitor C7, one end of which is connected to the cathode of the diode D3, the other end of which is respectively connected to one end of the grounding resistor R14 and the anode of the diode D4, the cathode of the diode D4 is respectively connected to one end of the grounding capacitor C8 and the upper end of the timing break switch K2, and the lower end of the timing break switch K2 is connected to the ground.

[0008] Preferably, the integral compensation circuit includes one end of a resistor R15 connected to the cathode of a diode D4, the other end of the resistor R15 respectively connected to one end of a grounding capacitor C9, the cathode of a voltage regulator tube Z2, and one end of the resistor R15, and the anode of the voltage regulator tube Z2 and the other end of the resistor R15 are connected to the in-phase input of an operational amplifier AR2.

[0009] The utility model improves the accuracy of pressure signal detection by denoising the pressure signal;

[0010] By comparing the hysteresis of the de-noised pressure signal with the set value, recharging + bidirectional diode conduction + fast trigger transistor conduction control can reduce disturbance and improve stability.

[0011] The change rate and time integral of the denoised pressure signal are calculated, and the denoised pressure signal is compensated inversely in time to achieve pressure signal prediction and timely control switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the circuit schematic diagram of the utility model.

[0013] Figure 2 This is a module diagram of the utility model. DETAILED DESCRIPTION

[0014] For the above and other technical contents, features and functions of the present invention, please refer to the following attached Figures 1 to 2 The detailed description of the embodiments will clearly show that the structural contents mentioned in the following embodiments are all based on the drawings in the specification.

[0015] Various exemplary embodiments of the present utility model will be described below with reference to the accompanying drawings.

[0016] The pump switching control system for non-stop lubrication in the thin oil station includes an oil tank, an oil pump, a one-way valve, a double-cylinder mesh oil filter, and a shell-and-tube oil cooler. The oil is sucked out from the oil tank by the oil pump, and is directly sent to the equipment for lubrication through the one-way valve, the double-cylinder mesh oil filter, and the shell-and-tube oil cooler. The oil pump includes a working pump and a standby pump, and is provided with a pressure sensor, a denoising circuit, a threshold comparison circuit, a steady-state trigger circuit, a change rate calculation circuit, and an integral compensation circuit. The system pressure signal detected by the pressure sensor is connected to the denoising circuit.

[0017] The denoising circuit is connected to a threshold comparison circuit and a change rate calculation circuit. The threshold comparison circuit is connected to a steady-state trigger circuit. The steady-state trigger circuit switches a working pump and a standby pump. The change rate calculation circuit is connected to an integral compensation circuit. The integral compensation circuit is connected to the threshold comparison circuit.

[0018] On the basis of the above technical solution, the denoising circuit receives the pressure signal detected by the pressure sensor, such as TXY, output signal 4-20mA, and pressure signal with a range of 1Mpa, and converts the 4-20mA current signal into a voltage signal through the impedance formed by the parallel resistor R2 and capacitor C1, and then suppresses the common-mode interference through the differential mode capacitor C2, the common mode capacitors C3 and C4, and enters the operational amplifier AR1 for differential amplification, wherein the series resistors R1 and R3, and the resistor R4 are the input resistors of the operational amplifier AR1, the resistor R5 is the feedback resistor, and the capacitor C5 is the feedback capacitor. The capacitor C5, the resistors R1 and R3, and the grounded capacitor C3 form a second-order low-pass filter, and the resistance value of the resistor and the capacitance value of the capacitor are set equal to form a Serenkai circuit, and a negative feedback is introduced in the second-order active circuit to make the output voltage drop rapidly in the high frequency band (that is, the low frequency band other than 4-20mA), and the passband gain is 1+R5 / R4. Finally, the diodes D1 and D2 are bidirectionally limited, and the diode D3 is unidirectionally conductive to output a 0-5V voltage, so as to denoise the pressure signal and improve the accuracy of pressure signal detection. The upper end of the capacitor C1, the upper end of the resistor R2, and the left end of the resistor R1 are respectively connected to the + signal output by the pressure sensor, the lower end of the capacitor C1, the lower end of the resistor R2, and the left end of the resistor R4 are respectively connected to the - signal output by the pressure sensor, the other end of the resistor R1 is respectively connected to one end of the resistor R3 and one end of the capacitor C5, and the other end of the resistor R3 is respectively connected to One end of the grounded capacitor C3, one end of the capacitor C2, and the non-inverting input end of the operational amplifier AR1 are connected. The other end of the resistor R4 is respectively connected to one end of the grounded capacitor C4, the other end of the capacitor C2, the inverting input end of the operational amplifier AR1, and one end of the resistor R5. The output end of the operational amplifier AR1 is respectively connected to the other end of the capacitor C5, the other end of the resistor R5, the anode of the diode D1, the cathode of the diode D2, and the anode of the diode D3. The cathode of the diode D1 is connected to the power supply +5V0, the anode of the diode D2 is connected to the ground, and the cathode of the diode D3 is the output signal of the de-noising circuit.

[0019] On the basis of the above technical solution, the threshold comparison circuit receives the de-noised pressure signal, and after filtering, enters the non-inverting input terminal of the operational amplifier AR2, the inverting input terminal of the operational amplifier AR2 is connected to the set value, and the output terminal of the operational amplifier AR2 is connected to the bidirectional voltage regulator VZ1, which plays the role of hysteresis comparison and outputs stable high and low levels, including resistor R6, capacitor C6, resistor R7, the grounded resistor R6, one end of the grounded capacitor C6, and one end of the resistor R7 are connected to the cathode of the diode D3, and the other end of the resistor R7 is respectively connected to one end of the grounded resistor R8 and the non-inverting input terminal of the operational amplifier AR2, and the operational amplifier A The inverting input end of R2 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to the adjustable end of the potentiometer RP1, the upper end of the potentiometer RP1 is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the negative electrode of the voltage regulator Z1 and one end of the resistor R9, the other end of the resistor R9 is connected to the power supply +5V0, the positive electrode of the voltage regulator Z1 is connected to the ground, the VCC of the operational amplifier AR2 is connected to the power supply +5V0, the GND of the operational amplifier AR2 is connected to the ground, the output end of the operational amplifier AR2 and one end of the bidirectional voltage regulator VZ1 are the output signals of the threshold comparison circuit, and the other end of the bidirectional voltage regulator VZ1 is connected to the ground.

[0020] On the basis of the above technical scheme, the steady-state trigger circuit receives the high and low levels of the hysteresis comparison, and then charges the capacitor C10 through the resistor R12. When the charging reaches the conduction value of the bidirectional diode SD1, it is determined that the non-instantaneous system pressure is lower than the set value. After the bidirectional diode SD1 is turned on, the transistor Q1 is quickly triggered to be turned on through the diode D5 and the resistor R13, and the control relay K1 coil is energized, and the normally closed contact K1-2 or the normally open contact K1-3 is connected in parallel to the two groups of contacts of the three-phase air switch QF3 for control, or the normally closed contact or the normally open contact is respectively connected to the positive or negative signal, which is transmitted to the central control, and the two groups of contacts of the three-phase air switch QF3 are driven by the central control, so as to compare the hysteresis of the de-noised pressure signal, and then charge + bidirectional diode conduction + fast trigger transistor conduction control to reduce disturbance, and then perform stability analysis before the pump is operated. The line switching can reduce disturbance and improve stability, and comprises a resistor R12, one end of the resistor R12 is connected to the output end of the operational amplifier AR2, the other end of the resistor R2 is respectively connected to one end of the grounding capacitor C10 and the left end of the bidirectional diode SD1, the right end of the bidirectional diode SD1 is respectively connected to the cathode of the diode D5 and one end of the resistor R13, the anode of the diode D5 is connected to the ground, the other end of the resistor R13 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is connected to the ground, the collector of the transistor Q1 is connected to one end of the normally closed contact K1-4 of the relay K1, the other end of the normally closed contact K1-4 of the relay K1 is respectively connected to one end of the relay K1 coil and the anode of the diode D6, the other end of the relay K1 coil and the cathode of the diode D6 are connected to the power supply +5V0, and the break contact K1-3 of the relay K1 switches the working pump and the standby pump.

[0021] On the basis of the above technical solution, the change rate calculation circuit uses capacitor C7, resistor R14, diode D4, and grounded capacitor C8 to calculate the change rate of the de-noised pressure signal. Specifically, capacitor C7 and resistor R14 are connected in series, diode D4 is used for rectification, capacitor C8 accumulates charges corresponding to the time change rate of voltage dv / dt, the negative electrode of diode D4 outputs a DC signal of a voltage level corresponding to the accumulated charge of capacitor C8, and the timing break switch K2 controls reset, including capacitor C7, one end of capacitor C7 is connected to the negative electrode of diode D3, the other end of capacitor C7 is respectively connected to one end of grounded resistor R14 and the positive electrode of diode D4, the negative electrode of diode D4 is respectively connected to one end of grounded capacitor C8 and the upper end of timing break switch K2, and the lower end of timing break switch K2 is connected to ground.

[0022] On the basis of the above technical scheme, the integral compensation circuit receives the rate of change signal, adopts the time integration of the resistor R15 and the capacitor C9, and the integrated signal is de-compensated and de-noised pressure signal through the inverse time conduction of the voltage regulator Z2 and the resistor R15, so as to realize the prediction of the pressure signal and timely control switching, including one end of the resistor R15 connected to the cathode of the diode D4, the other end of the resistor R15 is respectively connected to one end of the grounded capacitor C9, the cathode of the voltage regulator Z2, and one end of the resistor R15, and the anode of the voltage regulator Z2 and the other end of the resistor R15 are connected to the in-phase input terminal of the operational amplifier AR2.

[0023] The above is a further detailed description of the present invention in combination with a specific implementation method, and it cannot be determined that the specific implementation of the present invention is limited to this; for technical personnel in the field of the present invention and related technical fields, based on the technical solution of the present invention, the expansion and replacement of operating methods and data should all fall within the protection scope of the present invention.

Claims

1. The pump switching control system for non-stop lubrication of the thin oil station includes an oil tank, an oil pump, a one-way valve, a double-cylinder mesh oil filter, and a tubular oil cooler. The oil is sucked out from the oil tank by the oil pump and directly sent to the equipment for lubrication through the one-way valve, the double-cylinder mesh oil filter, and the tubular oil cooler. It is characterized in that: The oil pump includes a working pump and a standby pump, and is provided with a pressure sensor, a denoising circuit, a threshold comparison circuit, a steady-state trigger circuit, a rate of change calculation circuit, and an integral compensation circuit. The pressure sensor is connected to the denoising circuit, the denoising circuit is connected to the threshold comparison circuit and the rate of change calculation circuit, the threshold comparison circuit is connected to the steady-state trigger circuit, the steady-state trigger circuit switches the working pump and the standby pump, the rate of change calculation circuit is connected to the integral compensation circuit, and the integral compensation circuit is connected to the threshold comparison circuit.

2. The pump switching control system for non-stop lubrication of a thin oil station as claimed in claim 1, characterized in that: The de-noising circuit includes a capacitor C1, a resistor R1, a resistor R2, and a resistor R4. The upper end of the capacitor C1, the upper end of the resistor R2, and the left end of the resistor R1 are respectively connected to the + signal output by the pressure sensor, the lower end of the capacitor C1, the lower end of the resistor R2, and the left end of the resistor R4 are respectively connected to the - signal output by the pressure sensor, the other end of the resistor R1 is respectively connected to one end of the resistor R3 and one end of the capacitor C5, the other end of the resistor R3 is respectively connected to one end of the grounded capacitor C3, one end of the capacitor C2, and the non-inverting input end of the operational amplifier AR1, the other end of the resistor R4 is respectively connected to one end of the grounded capacitor C4, the other end of the capacitor C2, the inverting input end of the operational amplifier AR1, and one end of the resistor R5, the output end of the operational amplifier AR1 is respectively connected to the other end of the capacitor C5, the other end of the resistor R5, the positive electrode of the diode D1, the negative electrode of the diode D2, and the positive electrode of the diode D3, the negative electrode of the diode D1 is connected to the power supply +5V0, the positive electrode of the diode D2 is connected to the ground, and the negative electrode of the diode D3 is the output signal of the de-noising circuit.

3. The pump switching control system for non-stop lubrication of a thin oil station as claimed in claim 1, characterized in that: The threshold comparison circuit includes a resistor R6, a capacitor C6, and a resistor R7. The grounded resistor R6, one end of the grounded capacitor C6, and one end of the resistor R7 are connected to the cathode of the diode D3. The other end of the resistor R7 is respectively connected to one end of the grounded resistor R8 and the non-inverting input end of the operational amplifier AR2. The inverting input end of the operational amplifier AR2 is connected to one end of the resistor R11. The other end of the resistor R11 is connected to the adjustable end of the potentiometer RP1. The upper end of the potentiometer RP1 is connected to one end of the resistor R10. The other end of the resistor R10 is respectively connected to the cathode of the voltage regulator tube Z1 and one end of the resistor R9. The other end of the resistor R9 is connected to the power supply +5V0. The positive electrode of the voltage regulator tube Z1 is connected to the ground. The VCC of the operational amplifier AR2 is connected to the power supply +5V0. The GND of the operational amplifier AR2 is connected to the ground. The output end of the operational amplifier AR2 and one end of the bidirectional voltage regulator tube VZ1 are the threshold comparison circuit output signals. The other end of the bidirectional voltage regulator tube VZ1 is connected to the ground.

4. The pump switching control system for non-stop lubrication of a thin oil station as claimed in claim 1, characterized in that: The steady-state trigger circuit includes a resistor R12, one end of which is connected to the output end of the operational amplifier AR2, the other end of which is respectively connected to one end of the grounding capacitor C10 and the left end of the bidirectional diode SD1, the right end of the bidirectional diode SD1 is respectively connected to the cathode of the diode D5 and one end of the resistor R13, the anode of the diode D5 is connected to the ground, the other end of the resistor R13 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is connected to the ground, the collector of the transistor Q1 is connected to one end of the normally closed contact K1-4 of the relay K1, the other end of the normally closed contact K1-4 of the relay K1 is respectively connected to one end of the relay K1 coil and the anode of the diode D6, the other end of the relay K1 coil and the cathode of the diode D6 are connected to the power supply +5V0, and the break contact K1-3 of the relay K1 switches the working pump and the standby pump.

5. The pump switching control system for non-stop lubrication of a thin oil station as claimed in claim 1, characterized in that: The change rate calculation circuit includes a capacitor C7, one end of which is connected to the cathode of the diode D3, the other end of which is respectively connected to one end of the grounding resistor R14 and the anode of the diode D4, the cathode of the diode D4 is respectively connected to one end of the grounding capacitor C8 and the upper end of the timing break switch K2, and the lower end of the timing break switch K2 is connected to the ground.

6. The pump switching control system for non-stop lubrication of a thin oil station as claimed in claim 1, characterized in that: The integral compensation circuit includes one end of a resistor R15 connected to the cathode of a diode D4, the other end of the resistor R15 respectively connected to one end of a grounded capacitor C9, the cathode of a voltage regulator tube Z2, and one end of the resistor R15, and the anode of the voltage regulator tube Z2 and the other end of the resistor R15 are connected to the non-inverting input of an operational amplifier AR2.

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