CN113586723B

CN113586723B - Automatic fluid infusion system of oxidation kettle mechanical seal

Info

Publication number: CN113586723B
Application number: CN202110895334.XA
Authority: CN
Inventors: 陈卫东
Original assignee: Nantong Jiangshan Agrochemical and Chemicals Co Ltd
Current assignee: Nantong Jiangshan Agrochemical and Chemicals Co Ltd
Priority date: 2021-08-05
Filing date: 2021-08-05
Publication date: 2025-08-01
Anticipated expiration: 2041-08-05
Also published as: CN113586723A

Abstract

The present application discloses an automatic liquid replenishing system for the mechanical seal of an oxidation kettle, which comprises a liquid storage tank, a pump A, a liquid chamber of a balance cylinder, and a liquid seal chamber of a mechanical seal arranged in sequence according to the liquid flow path; in addition, a compressed gas tank B, a pneumatic pump B, and a gas chamber of a balance cylinder are arranged in sequence according to the gas flow path. A cylinder piston is located between the gas chamber and the liquid chamber, and the reciprocating motion of the piston can change the relative volume of the two chambers. In addition, a controller is provided, and a liquid level signaler is connected to the liquid chamber. The controller controls the start and stop of pump A and pneumatic pump B respectively, thereby maintaining the liquid level in a suitable range between the upper and lower liquid level sensors. The present invention can effectively prevent the mechanical seal from being damaged due to lack of water through the automatic control of the controller, thereby increasing the service life of the mechanical seal.

Description

Automatic fluid infusion system of oxidation kettle mechanical seal

Technical Field

The invention relates to a fluid infusion technology of a mechanical sealing element.

Background

The mechanical seal is a shaft seal device of a rotary machine. Such as centrifugal pumps, centrifuges, kettles, compressors and the like. Since the drive shaft extends through the device and is thus located inside and outside the device, there is a circumferential gap between the shaft and the device through which the medium in the device leaks outwards, and if the pressure in the device is below atmospheric pressure, air leaks into the device, so that a shaft seal means for preventing leakage is necessary.

The key to successful mechanical sealing is to form and maintain a liquid film with a certain thickness, and reasonable pressure per unit area must be controlled between the end surfaces to maintain the liquid film, so that a higher mechanical sealing technical level is obtained, and the service life of the mechanical sealing is effectively prolonged.

Glyphosate is a systemic, efficient, broad-spectrum, nuisance-free, safe herbicide, and has a great deal of weight in the global pesticide market. The common synthesis route of glyphosate is divided into glycine route and iminodiacetic acid (IDA) route, the IDA method uses iminodiacetic acid as main raw material, and the iminodiacetic acid is synthesized with phosphorus trichloride to form the N-phosphonomethyl iminodiacetic acid which is oxidized into the glyphosate. In the preparation process, the oxidation reaction is required to be carried out in an oxidation kettle under the stirring action of a blade. In the use process of the oxidation kettle, the stirrer seal is easy to burn out due to heating caused by water shortage, and the production is further affected. The byproduct formaldehyde in this reaction is a highly hazardous chemical and is strongly irritating to mucous membranes, upper respiratory tract, eyes and skin.

Therefore, the sealing performance of the machine seal needs to be well ensured, the liquid supplementing of liquid (water or oil) in the traditional oxidation kettle machine seal is controlled manually, the timely, accurate and effective water supplementing cannot be realized, the machine seal damage phenomenon occurs, the maintenance rate is high, the use and production progress of the oxidation kettle are seriously influenced, and the machine seal leakage is harmful to human bodies and the environment.

Disclosure of Invention

The invention aims to:

the automatic liquid supplementing system for the oxidation kettle seal can automatically supplement liquid in the kettle seal, and can ensure proper metering and high safety.

The technical scheme is as follows:

The invention provides an automatic liquid supplementing system for an oxidation kettle machine seal, which is provided with a liquid storage tank and a pump A (preferably a pneumatic pump, provided with a compressed air tank A) which are sequentially arranged according to a liquid flow path, so that an electric pump is not used, electric spark is not generated, the safety to an oxidizing material is high, left side compressed air, pneumatic driving liquid, no electricity and safe explosion are generated), a liquid chamber of a balance cylinder (which is provided with a liquid chamber, a piston and a gas chamber from top to bottom) and a liquid sealing chamber of a mechanical sealing member, and a compressed air tank B (right compressed air enters a lower chamber of the balance cylinder, drives a piston to go upwards, and liquid enters or returns to an upper chamber of the balance cylinder to play a sealing role), and the pneumatic pump B and the gas chamber of the balance cylinder.

The liquid cavity of the balance cylinder and the liquid seal cavity of the mechanical sealing element are provided with a liquid transmission channel and a liquid backflow channel, so that the volume of liquid in the liquid seal cavity can timely change along with the movement of a piston in the balance cylinder.

The cylinder piston is arranged between the gas chamber and the liquid chamber, and the reciprocating motion of the piston can change the relative volume of the two chambers, so that the quantity of liquid entering or flowing back into the liquid sealing cavity of the mechanical sealing element is regulated, the sealing performance of the liquid sealing cavity changes along with the change, and the damage to the mechanical sealing element caused by the lack of liquid in the liquid sealing cavity of the mechanical sealing element can be effectively avoided.

The balance cylinder shell is provided with a cooling water coil pipe, so that the temperature of the balance cylinder body is conveniently reduced, the liquid temperature is reduced, overheat and overvoltage are prevented, and the lubrication and sealing effects of the machine sealing piece are prevented from being influenced by liquid gasification.

When the upper piston plate is positioned between the two sensors, the pneumatic pump A can be started for a while, and surplus liquid and potential energy thereof are temporarily stored in the accumulator, so that the liquid in the balance cylinder can be compensated in time, and the pneumatic pump A is not required to be started and stopped too frequently.

And the other branch of the pressure relief valve is communicated with the liquid storage tank, so that excessive liquid (or air pressure of the pump A) in the relief pipeline is conveniently refluxed to the liquid storage tank.

The combined application of the energy accumulator and the pressure relief valve ensures that the amount of liquid in the balance cylinder and the pressure in the pneumatic pump B can maintain good east balance, and the self-adjusting capacity is stronger. A small amount of energy surplus in the pipeline can be collected and utilized, but excessive pressure cannot occur, and the sealing effect of the system cannot be affected too much.

Preferably, the liquid is soft water (good in water quality and capable of avoiding inorganic matter precipitation and scaling), the mechanical sealing element adopts soft water as a liquid seal, and a circle of water-resistant sealing ring (preferably ethylene propylene diene monomer rubber sealing ring with good weather resistance, ozone resistance, water resistance and chemical resistance) is arranged at the contact part of the mechanical sealing element and the soft water, and the mechanical sealing element uses a sealing element of an oxidation kettle to avoid that oil contacts with oxide and is easy to burn and explode. Meanwhile, the surface tension of the water is larger than that of a common oiling agent, so that the leakage phenomenon is less likely to occur at a sealing part. Even if there is a leak, water is liable to volatilize (particularly, the mechanical seal rubs to generate heat after use, so that water evaporates by vaporization), and oil is liable to contaminate the mechanical surface.

Preferably, a filtering and decompressing two-way piece is arranged between the compressed air tank A and the pneumatic pump A, gas purification ensures that the gas chamber of the balance cylinder and the piston of the balance cylinder have small friction loss and the service life is prolonged, decompression ensures that the pressure of the pneumatic pump A is not too large, the liquid flow is relaxed, and the pressure of the balance cylinder is regulated slowly.

The controller is connected with the start and stop of the pneumatic pump A and the pneumatic pump B respectively or connected with the pressure relief valve.

In addition, be connected with the liquid level signal ware at liquid cavity, the liquid level signal ware can connect the liquid level signal of gathering two liquid level sensor about respectively.

The liquid level signal device and the controller are provided with signal connecting lines, when the upper liquid level sensor and the lower liquid level sensor are respectively touched by the upper piston plate or can not be touched, the controller respectively controls the starting or stopping of the pneumatic pump A and the pneumatic pump B, so that the liquid level is maintained in a proper interval between the upper liquid level sensor and the lower liquid level sensor.

I.e. when the upper piston plate is below the lower level sensor, indicating that the liquid chamber is too large and too much liquid, the controller controls the pneumatic pump B to start or accelerate the flow so that compressed air is increased into the gas chamber pushing the piston upward. At this time, the pressure relief valve may be opened to allow the liquid to flow back to the reservoir. When the upper piston plate is higher than the upper liquid level sensor, the liquid chamber is too small, the liquid is too little, and the controller controls the pneumatic pump A to start or accelerate the flow, so that the liquid is compensated to enter the liquid chamber.

Preferably, the air pressure generated by the air pump A is larger than the air pressure generated by the air pump B, and the pressure difference between the air pressure and the air pressure is between 0.2MPa and 0.6 MPa. So that the pressure difference can maintain the proper liquid height and pressure in the liquid chamber, and is not too high, the leakage is avoided, the load of the balance rod is increased, and the proper liquid volume and liquid pressure required by the sealing are ensured.

After the pneumatic pump or the energy accumulator, a unit consisting of a plurality of sets of balance cylinders, mechanical sealing elements and compressed air B which are connected in parallel can be arranged, so that the liquid storage tank can be shared by the liquid supplementing of the mechanical sealing elements.

The beneficial effects are that:

The automatic water supplementing system of the machine seal is high in stability, and damage of the machine seal caused by water shortage can be effectively avoided through automatic control of the controller, missing or redundant liquid can be timely supplemented, the service life of the machine seal is prolonged, the failure rate of equipment is reduced, and the influence of machine seal overhaul on production is reduced. Meanwhile, the energy accumulator and the pressure release valve are combined, so that stable operation of production is effectively ensured, energy is saved, consumption is reduced, cost is lowered, and efficiency is improved.

Drawings

FIG. 1 is a schematic diagram of the connection structure of the components of the sealing system of the water replenishing system of the present invention;

In the figure, a liquid storage tank 1-a filter 2-a liquid valve 3-a liquid chamber 4-a filtering and depressurizing two-way component 5-a pneumatic pump 6-a pressure relief valve 7-an energy accumulator 8-a controller 9-a gas valve 10-a mechanical sealing element 11-a liquid level signal device (comprising two liquid level sensors), a liquid chamber 12-a balancing cylinder 13-a gas chamber 14-a balancing cylinder.

Detailed Description

The automatic liquid supplementing system for the oxidation kettle machine seal shown in fig. 1 comprises a liquid storage tank, a pump A, a liquid chamber of a balance cylinder and a liquid sealing chamber of a mechanical sealing element which are sequentially arranged according to a liquid flow path, and a compressed gas tank B, a pneumatic pump B and a gas chamber of the balance cylinder which are sequentially arranged according to a gas flow path. Between the gas chamber and the liquid chamber is a cylinder piston, the piston reciprocating to adjust the amount of liquid that enters or returns to the liquid seal cavity of the mechanical seal. An energy accumulator is arranged between the pneumatic pump A and the balance cylinder, and surplus liquid and potential energy thereof are temporarily stored in the energy accumulator. A pressure relief valve is arranged between the pneumatic pump A and the energy accumulator.

In addition, the liquid chamber is connected with a liquid level signal device, and the liquid level signal device and the controller are provided with signal connecting wires. The controller controls the start or stop of the pneumatic pump A and the pneumatic pump B respectively, and maintains the liquid level between the upper liquid level sensor and the lower liquid level sensor.

The mechanical seal automatic water supplementing system can comprise the following operation steps:

The starting step:

(1) The right side compressed air source was turned on to stabilize the compressed air pressure at 0.7MPaG. (2) And confirming that the remote transmission pressure, namely the pressure of the fluid infusion system, is stable at 1.05MPaG. (3) The balance tank (balance cylinder) pressurization port valve was opened, and the balance tank gas chamber pressure was raised to an operating pressure of 0.6MPaG. 5) Monitoring the pipeline pressure of the system, and judging whether the liquid levels in the liquid storage tank and the balance tank are normal.

And (3) stopping:

(1) And closing the balance cylinder air inlet valve, opening the meter valve vent hole, and discharging the pressure of the balance tank gas chamber. (2) And opening a liquid injection port valve, filling sealing liquid to the limit range of the piston, and closing the liquid injection port valve. (3) Closing the compressed air source, opening the pressure relief valve to relieve the pressure of the fluid supplementing section.

Claims

1. An automatic liquid replenishing system for an oxidation kettle mechanical seal, characterized by comprising: a liquid storage tank, a pneumatic pump A, a liquid chamber of a balancing cylinder, and a liquid seal chamber of a mechanical seal, arranged in sequence along a liquid flow path; and a compressed gas tank B, a pneumatic pump B, and a gas chamber of the balancing cylinder, arranged in sequence along a gas flow path;

The balancing cylinder is composed of the liquid chamber, the cylinder piston, and the gas chamber. The liquid chamber is provided with an upper piston plate, and the cylinder piston is located between the gas chamber and the liquid chamber. The reciprocating motion of the cylinder piston can adjust the amount of liquid entering the liquid chamber or flowing into the liquid seal chamber.

There is also a controller, which is connected to control the start and stop of the pneumatic pump A and the pneumatic pump B respectively;

In addition, the liquid chamber is connected to a liquid level signaler, which includes two upper and lower liquid level sensors, and a signal connection line is provided between the liquid level signaler and the controller;

An accumulator is provided between the pneumatic pump A and the balancing cylinder, and the surplus liquid and its potential energy are temporarily stored in the accumulator. A pressure relief valve is provided between the pneumatic pump A and the accumulator;

There is a liquid transmission channel and a liquid return channel between the liquid chamber of the balancing cylinder and the liquid seal cavity of the mechanical seal, so that the volume of the liquid in the liquid seal cavity changes in time with the movement of the piston in the balancing cylinder;

The liquid is soft water, and the mechanical seal uses soft water as liquid seal. The mechanical seal is used as the oxidation kettle seal;

The liquid level signal device can be connected to collect liquid level signals from the upper and lower liquid level sensors respectively; the controller controls the start or stop of the pneumatic pump A and the pneumatic pump B respectively to maintain the liquid level between the upper and lower liquid level sensors; when the upper piston plate is lower than the lower liquid level sensor, it indicates that the liquid chamber is too large and there is too much liquid. The controller controls the pneumatic pump B to start or accelerate the flow, so that more compressed air enters the gas chamber and pushes the cylinder piston upward. At this time, the pressure relief valve opens to allow the liquid to flow back to the liquid storage tank; when the upper piston plate is higher than the upper liquid level sensor, it indicates that the liquid chamber is too small and there is too little liquid. The controller controls the pneumatic pump A to start or accelerate the flow, and the liquid compensates and enters the liquid chamber;

After the accumulator, there are multiple sets of parallel-connected balancing cylinders, mechanical seals and compressed air units, so that the liquid storage tank is used to replenish the liquid of multiple mechanical seals;

The air pressure generated by the pneumatic pump A is greater than the air pressure generated by the pneumatic pump B, and the pressure difference between the two is between 0.2MPa and 0.6MPa;

There is a circle of EPDM rubber sealing ring where the mechanical seal contacts the soft water.