CN116733726A - An interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump - Google Patents

Abstract

An interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump, including a hydraulic diaphragm metering pump, an input pipe and an output pipe connected to the hydraulic diaphragm metering pump, the input pipe and the output pipe are respectively provided with a liquid inlet valve and a liquid outlet valve , the output pipe is located at the front end of the liquid outlet valve, and a pressure gauge is installed, as well as an accumulator connected to the output pipe. The back end of the accumulator is connected to a pressure relief valve; the outlet of the hydraulic diaphragm metering pump is equipped with a pressure transmitter, and the hydraulic The motor of the diaphragm metering pump is connected with an ammeter for monitoring the motor current and a solenoid valve for controlling the operation or shutdown of the motor. The pressure transmitter, ammeter and solenoid valve are respectively connected to the host computer signal, and the pressure transmitter and ammeter monitor them. The value is sent to the host computer in real time, and the host computer compares the obtained pressure value and current value with the preset value. When the pressure value and current value are greater than or equal to the preset value, the host computer sends a signal to the solenoid valve to disconnect and shut down the motor. . The invention has simple and reliable operation, low cost and high safety.

Description

An interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump

Technical field

The invention relates to the technical field of metering pumps, and in particular to an interlocking device and an interlocking method for avoiding overpressure at the outlet of a hydraulic diaphragm metering pump.

Background technique

Hydraulic diaphragm metering pump, also called plunger diaphragm metering pump, is a metering pump designed by combining the characteristics of plunger metering pump and diaphragm metering pump. The part in contact with the metered medium is the diaphragm, and the driving part is the hydraulic plunger. The driving gear drives the hollow plunger to reciprocate, and drives the metering diaphragm through the hydraulic oil in the hollow plunger. There is a specially designed regulating air on the hollow plunger to make the hydraulic oil inside and outside the plunger the same. There is an adjustable slip ring on the outside of the plunger for closing the adjustment cavity. When the adjustment hole is closed, the plunger pushes the hydraulic oil inside to drive the metering diaphragm. In each stroke, the amount of hydraulic oil pushed by the plunger to drive the metering diaphragm is exactly equal to the amount of medium being metered. The flow rate of the metering pump can be adjusted through the manual knob on the plunger flange, or through a frequency converter, servo motor, etc.

Hydraulic diaphragm metering pumps can be widely used in industrial and technological sectors such as petroleum, chemicals, textiles, food, papermaking, atomic energy technology, power plants, plastics, pharmaceuticals, water plants, and environmental protection. It can achieve the purpose of accurate liquid measurement; it has the characteristics of leak-free liquid transportation; it can be applied to the transportation of flammable, explosive, volatile, highly corrosive, radioactive, highly toxic, suspension and expensive liquid media; it has the characteristics of high-pressure liquid transportation . However, the main disadvantage is that the pump outlet is prone to overpressure, which can easily lead to serious accidents. At present, it is commonly used at home and abroad to install a safety valve at the pump outlet (see Figure 1). When the pump outlet is overpressured and reaches the safety valve relief pressure, safety The valve begins to release pressure until the pressure returns to normal and the safety valve returns to its seat to close, thus preventing overpressure at the pump outlet.

This method can achieve the purpose of avoiding overpressure at the pump outlet under some conditions, but there are still great safety hazards and defects. For example, when the transport medium is easy to crystallize and block the pipeline, the safety valve cannot guarantee normal pressure relief; the safety valve is a safety accessory. There is a possibility of failure, inaccurate calibration of relief pressure, or jamming. In this case, the safety valve cannot guarantee normal pressure relief; when the safety valve releases overpressure, it opens and discharges instantly. There is usually normal pressure or slightly positive pressure behind the safety valve. If the pump outlet pressure is high pressure or ultra-high pressure, once the overpressure is released, the high-pressure or ultra-high-pressure medium will instantly enter the normal pressure or slightly positive pressure equipment, which can easily lead to serious accidents. To sum up, the current method of installing a safety valve at the outlet of a hydraulic diaphragm metering pump cannot completely and effectively solve the problem of overpressure at the pump outlet.

Contents of the invention

In response to the above technical problems, this technical solution provides an interlocking device and interlocking method to avoid overpressure at the outlet of a hydraulic diaphragm metering pump. When the pump outlet is overpressured, the motor of the hydraulic diaphragm metering pump is turned off, the motor is stopped, and the The hydraulic plunger works to adjust the flow rate of the metering pump, thereby reducing the pressure at the outlet of the hydraulic diaphragm metering pump; it can effectively solve the above problems.

The present invention is realized through the following technical solutions:

An interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump, including a hydraulic diaphragm metering pump, an input pipe and an output pipe respectively connected to the inlet and outlet of the hydraulic diaphragm metering pump, and the input pipe and the output pipe are respectively provided with liquid inlet valves and a liquid outlet valve. On the output pipe, a pressure gauge is installed at the front end of the liquid outlet valve, and an accumulator is connected to the output pipe. The rear end of the accumulator is connected to a pressure relief valve; the outlet of the hydraulic diaphragm metering pump A pressure transmitter is installed. The motor of the hydraulic diaphragm metering pump is connected with an ammeter for monitoring the motor current and a solenoid valve for controlling the operation or shutdown of the motor. The pressure transmitter, ammeter and solenoid valve are respectively connected to the host computer signal. The pressure The transmitter and ammeter send their monitoring values to the host computer in real time. The host computer compares the obtained pressure value and current value with the preset value. When the pressure value and current value are greater than or equal to the preset value, the host computer sends a signal to The solenoid valve is disconnected and the motor is shut down.

Further, the pressure transmitter, ammeter and solenoid valve are respectively connected to the host computer via cables.

Furthermore, the pressure transmitter, ammeter and solenoid valve are respectively equipped with wireless modules and are connected to the host computer via local area network signals.

An interlocking method to avoid overpressure at the outlet of a hydraulic diaphragm metering pump needs to be used in conjunction with the above-mentioned interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump. Set a high alarm value and a high interlocking value for the pressure transmitter, and set a high alarm value for the ammeter. Set high alarm value and high interlock value, establish interlock logic for both to prompt the hydraulic diaphragm metering pump to stop working, and debug the pressure transmitter, ammeter, solenoid valve and host computer and put them into normal operation.

Furthermore, the interlocking logic is a one-out-of-two logic, that is, when the monitoring value of either pressure transmitter or ammeter is greater than the set upper limit value, the interlocking will be triggered, and the solenoid valve will be triggered to disconnect, and the hydraulic The motor of the diaphragm metering pump has stopped running.

beneficial effects

The invention proposes an interlocking device and interlocking method for avoiding overpressure at the outlet of a hydraulic diaphragm metering pump. Compared with the existing technology, it has the following beneficial effects:

When the pump outlet is overpressured, the invention turns off the motor of the hydraulic diaphragm metering pump, stops the motor operation, stops the hydraulic plunger from working, and adjusts the flow rate of the metering pump, thereby reducing the pressure at the outlet of the hydraulic diaphragm metering pump; the operation is simple and reliable, and the cost is low Moreover, it has high safety and does not cause dangerous problems mentioned in the background technology.

Description of drawings

Figure 1 is a scheme diagram of the prior art in the background technology.

Figure 2 is a schematic diagram of the overall pipeline connection in Embodiment 1 of the present invention.

Figure 3 is a schematic diagram of the overall pipeline connection before rectification in Case 1.

Figure 4 is a schematic diagram of the overall pipeline connection in Case 1.

Figure 5 is the circuit schematic diagram of the pressure transmitter, ammeter and host computer in Case 1.

Figure 6 is the interface diagram of the host computer interlocking setting in Case 1.

Numbers in the drawings: 1-Hydraulic diaphragm metering pump, 11-inlet, 12-outlet, 13-motor, 21-input pipe, 22-output pipe, 3-liquid inlet valve, 4-liquid outlet valve, 5-pressure Table, 6-accumulator, 7-pressure relief valve, 8-pressure transmitter, 9-ammeter, 10-safety valve, 14-cable, 15-host computer.

Implementation

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary people in the art to the technical solution of the present invention shall fall within the protection scope of the present invention.

Example

As shown in Figure 2, an interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump includes a hydraulic diaphragm metering pump 1, an input pipe 21 and an output pipe 22 connected to the inlet 11 and outlet 12 of the hydraulic diaphragm metering pump 1 respectively. , the input pipe 21 and the output pipe 22 are respectively provided with a liquid inlet valve 3 and a liquid outlet valve 4. On the output pipe 22, a pressure gauge 5 is installed at the front end of the liquid outlet valve 4, and an accumulator connected with the output pipe 22 6. The rear end of the accumulator 6 is connected with a pressure relief valve 7.

A pressure transmitter 8 is installed at the outlet of the hydraulic diaphragm metering pump 1. The motor 13 of the hydraulic diaphragm metering pump 1 is connected to an ammeter 9 for monitoring the current of the motor 13 and a solenoid valve for controlling the operation or shutdown of the motor 13. The pressure variable The transmitter 8, the ammeter 9 and the solenoid valve are respectively connected with the signal of the host computer 15. The pressure transmitter 8 and the ammeter 9 send their monitoring values to the host computer 15 in real time. The host computer 15 compares the obtained pressure values and current values with the preset values. When the pressure value and current value are greater than or equal to the preset value, the host computer 15 sends a signal to the solenoid valve to disconnect and shut down the motor 13 to run.

The pressure transmitter 8, the ammeter 9 and the solenoid valve are respectively connected to the host computer 15 through cables 14, or through the cooperation of the wireless module and the local area network.

Example

An interlocking method to avoid overpressure at the outlet of a hydraulic diaphragm metering pump needs to be used in conjunction with the above-mentioned interlocking device to avoid overpressure at the outlet of a hydraulic diaphragm metering pump. Set a high alarm value and a high interlocking value for the pressure transmitter, and set a high alarm value for the ammeter. Set high alarm value and high interlock value, establish interlock logic for both to prompt the hydraulic diaphragm metering pump to stop working, and debug the pressure transmitter, ammeter, solenoid valve and host computer and put them into normal operation.

The interlocking logic is a one-out-of-two logic, that is, when the monitoring value of either pressure transmitter or ammeter is greater than the set upper limit, the interlocking will be triggered, the solenoid valve will be triggered to disconnect, and the hydraulic diaphragm metering pump will stop using.

In order to verify the effect of the above embodiment, the inventor uses cases to verify it. Specific cases are as follows:

Case 1:

In the hydrogenation workshop, interlocking equipment is installed on the dinitrate metering pump to protect it. Before the transformation, as shown in Figure 3, the mixed dinitrate enters the dinitrate metering pump P106 A/B/ from the dinitrate metering tank V106 A/B. C/D is pressurized and measured by a reciprocating diaphragm metering pump, and directly enters the hydrogenation primary reactor R101A/B to participate in the hydrogenation reaction.

Before the transformation, because the dinitrile metering pump was a reciprocating pump, when the metering pump was started, or during the operation of the metering pump, if the outlet pipe of the metering pump was not smooth, or there was material crystallization in the outlet pipe, it would cause failure of the metering pump. Overpressure at the outlet, if not discovered in time by personnel on site, can easily lead to damage to equipment and pipelines and serious safety accidents.

After transformation, it is shown in Figure 4. The mixed dinitrate is pressurized and metered through the metering pump P106A/B/C/D, and enters the hydrogenation primary reactor R101A/B to participate in the hydrogenation reaction.

It is planned to lead out an interface at the local pressure gauge at the outlet of the metering pump and install a pressure transmitter. The motor of the metering pump is connected with an ammeter for monitoring the motor current and a solenoid valve for controlling the operation or shutdown of the motor. The pressure transmitter, The ammeter and solenoid valve are connected to the host computer through cables respectively. The circuit schematic diagram of the pressure transmitter, ammeter and host computer is shown in Figure 5. The pressure transmitter and ammeter send their monitoring values to the host computer in real time. The host computer Compare the obtained pressure value and current value with the preset value. When the pressure value and current value are greater than or equal to the preset value, the host computer sends a signal to the solenoid valve to disconnect and shut down the motor.

The pressure transmitter and ammeter are used as interlocking conditions in the system to determine whether to stop the pump due to high pressure. In order to avoid triggering the interlock to stop the pump due to instrument failure, the pressure interlock and current interlock are set to one of the two to trigger the pump to stop. The interface diagram of the host computer interlocking setting is shown in Figure 6.

The metering pump model is a hydraulic diaphragm metering pump PJ25M-2000/2.5BP-RL1-RJ4-YB. The conveying medium is mixed dinitrobenzene. The high alarm value of the pump outlet pressure is set to 1.8MPa, and the high pressure interlock value is 2.0MPa. , the pump motor high current alarm value is 11A, and the high current interlock value is 13A.

The interlocking between the metering pump outlet pressure and the metering pump motor current was tested three times each. When the pump outlet pressure was greater than 2.0MPa and the pump motor current was greater than 13A, the interlock was successfully triggered to stop the hydraulic diaphragm pump.

During the start-up or operation of the modified dinitrate metering pump, if the pipeline is not smooth or the material crystallizes, resulting in overpressure at the metering pump outlet, it will cause the metering pump motor to overcurrent, causing the metering pump outlet pressure linkage to be triggered at the same time. The lock is interlocked with the motor current of the metering pump. After the interlock is triggered, the metering pump automatically stops running in an emergency, which can avoid damage to equipment and pipelines and avoid safety accidents.

Case 2

The metering pump model is a hydraulic diaphragm metering pump PJ25M-1000/1.0BP-RL1-RJ4-YB. The conveying medium is methanol. The high alarm value of the outlet pressure of the metering pump is set to 0.6MPa, and the high pressure interlock value is set to 0.8MPa. The metering pump The motor current high alarm value is set to 3A, and the current high interlock value is set to 5A. The metering pump outlet pressure and the metering pump motor current interlock are tested 3 times each. When the metering pump outlet pressure is greater than 0.8MPa, the metering pump motor current is greater than At 5A, the interlock was successfully triggered to stop the hydraulic diaphragm pump.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes, substitutions and improvements within the technical scope disclosed in the present invention are within the protection scope of the present invention.

Claims (5)

1. An interlocking device for preventing the excessive pressure of an outlet of a hydraulic diaphragm metering pump comprises the hydraulic diaphragm metering pump (1), an input pipe (21) and an output pipe (22) which are respectively connected with an inlet (11) and an outlet (12) of the hydraulic diaphragm metering pump (1), a liquid inlet valve (3) and a liquid outlet valve (4) are respectively arranged on the input pipe (21) and the output pipe (22), a pressure gauge (5) is arranged at the front end of the liquid outlet valve (4) and an energy accumulator (6) communicated with the output pipe (22), and a pressure release valve (7) is connected at the rear end of the energy accumulator (6); the method is characterized in that: the pressure transmitter (8) is installed in the export (12) of hydraulic pressure diaphragm metering pump (1), motor (13) of hydraulic pressure diaphragm metering pump (1) are connected with ampere meter (9) that are used for monitoring motor (13) electric current and are used for controlling motor (13) operation or closed solenoid valve, pressure transmitter (8), ampere meter (9) and solenoid valve respectively with host computer (15) signal connection, pressure transmitter (8) and ampere meter (9) send its monitoring value to host computer (15) in real time, host computer (15) compares the pressure value and the current value that will obtain with the interlock value of predetermineeing, when pressure value and current value are greater than or equal to the interlock value of predetermineeing, host computer (15) sends signal to solenoid valve disconnection, shut down motor (13) operation.

2. An interlock for avoiding excess pressure at the outlet of a hydraulic diaphragm metering pump as claimed in claim 1 wherein: the pressure transmitter (8), the ammeter (9) and the electromagnetic valve are respectively connected with the upper computer (15) through cables (14) in a signal mode.

3. An interlock for avoiding excess pressure at the outlet of a hydraulic diaphragm metering pump as claimed in claim 1 wherein: the pressure transmitter (8), the ammeter (9) and the electromagnetic valve are respectively provided with a wireless module and are connected with the upper computer (15) through a local area network in a signal mode.

4. An interlocking method for avoiding overpressure at the outlet of a hydraulic diaphragm metering pump, which is used with the interlocking device for avoiding overpressure at the outlet of the hydraulic diaphragm metering pump according to any one of claims 1 to 3, and is characterized in that: setting a high alarm value and a high interlocking value for the pressure transmitter (8), setting a high alarm value and a high interlocking value for the ammeter (9), establishing interlocking logic for the high alarm value and the high interlocking value for the ammeter to enable the hydraulic diaphragm metering pump (1) to stop working, and debugging the pressure transmitter (8), the ammeter (9), the electromagnetic valve and the upper computer (15) normally for use.

5. An interlocking method for avoiding excess pressure at the outlet of a hydraulic diaphragm metering pump according to claim 1, wherein: the interlocking logic is two-in-one logic, namely, after any one of the monitoring values of the pressure transmitter (8) and the ammeter (9) is larger than the set upper limit value, the interlocking is triggered, the electromagnetic valve is triggered to be disconnected, and the motor of the hydraulic diaphragm metering pump (1) stops running.