CN204573587U - A kind of air cooling Roots pendular ring closed vacuum system - Google Patents

Abstract

The utility model relates to the field of vacuum pumps, in particular to an air-cooled Roots liquid-ring closed vacuum system, comprising an air-cooled Roots pump and a liquid-ring vacuum pump on the main gas pipeline, and a liquid-ring vacuum pump at the input end of the main gas pipeline. The first gas control valve, air-cooled Roots pump, gas cooler, and second gas control valve are sequentially connected in series between the input ends, and a gas pressure differential switch is set on the pipeline at the front end of the first gas control valve. A gas pressure transmitter is arranged on the pipeline between the valve and the air-cooled Roots pump, and a return pipeline is arranged between the air-cooled Roots pump and the gas cooler. The utility model has high operating efficiency, can save more than 70% of electricity and water of more than 40% on average, and has the advantages of high ultimate vacuum, low failure rate, small occupied space, etc., and can be widely used in condenser systems of power plants.

Description

An Air Cooled Roots Liquid Loop Closed Vacuum System

technical field

The utility model relates to the field of vacuum pumps, in particular to an air-cooled Roots liquid-loop closed vacuum system.

Background technique

In the condenser system of a power plant, a vacuum pump is generally used for vacuuming, and the inlet vacuum range is -0.098MPa～-0.092MPa. The vacuum pump currently used is generally a liquid ring vacuum pump, and the liquid ring vacuum pump uses liquid as the working fluid for vacuuming. When the temperature of the working fluid is high, not only the suction volume drops more seriously, but also it is easy to cause damage due to cavitation. The liquid ring vacuum pump also has problems such as large water consumption, low operating efficiency, and high failure rate.

Patent No. "201310006450.7" is a utility model patent "A device and method for maintaining vacuum in a thermal power plant condenser", which discloses a combination of a Roots pump and a liquid ring vacuum pump, but does not propose how to control it in practical applications. feasible solution, so that it is completely unrealizable in practical applications.

Utility model content

Aiming at the deficiencies of the prior art, the utility model proposes a high-efficiency, energy-saving air-cooled Roots liquid-loop closed cycle vacuum system and its control method, and adopts the following technical scheme:

An air-cooled Roots liquid-ring closed vacuum system, comprising an air-cooled Roots pump and a liquid ring vacuum pump arranged on the main gas pipeline, and a first series connection between the input end of the main gas pipeline and the input end of the liquid ring vacuum pump. Gas control valve, air-cooled Roots pump, gas cooler, second gas control valve, a gas pressure differential switch is installed on the pipeline at the front end of the first gas control valve, between the first gas control valve and the air-cooled Roots pump A gas pressure transmitter is set on the pipeline, and a return line is set between the air-cooled Roots pump and the gas cooler.

Further, the first gas control valve, the second gas control valve, the gas differential pressure switch and the gas pressure transmitter are all connected to the distributed control system (DCS system for short).

More preferably, a gas supply pipeline is provided on the pipeline between the gas cooler and the second gas control valve, a third gas control valve is provided on the gas supply pipeline, and the third gas control valve communicates with the DCS system.

The utility model has the following advantages and positive effects:

The utility model has high operation efficiency, can save more than 70% of electricity and more than 40% of water on average, and also has the advantages of high ultimate vacuum, low failure rate, small occupied space, etc., and can be widely used in condenser systems of power plants.

Below in conjunction with accompanying drawing and specific embodiment, the utility model is described in further detail.

Description of drawings

Fig. 1 is a structural representation of the utility model.

Detailed ways

Fig. 1 is a structural representation of the utility model. As shown in Figure 1, an air-cooled Roots liquid-ring closed vacuum system includes an air-cooled Roots pump 2 and a liquid ring vacuum pump 3 on the main gas pipeline 1, and a liquid ring vacuum pump 3 at the input end of the main gas pipeline 1. The first gas control valve 4, the air-cooled Roots pump 2, the gas cooler 5 and the second gas control valve 6 are sequentially connected in series between the input ends of the ring vacuum pump 3, and the gas pressure is set on the pipeline at the front end of the first gas control valve 4. A differential switch 7, a gas pressure transmitter 8 is installed on the pipeline between the first gas control valve 4 and the air-cooled Roots pump 2, and a return pipeline 9 is installed between the air-cooled Roots pump 2 and the gas cooler 5 The function of setting the first gas control valve 4 is to cut off the vacuum unit and the vacuum system to prevent the backflow of gas; the function of setting the second gas control valve 6 is to prevent the backflow of the working fluid when the liquid ring vacuum pump 3 is shut down.

The first gas control valve 4, the second gas control valve 6, the gas differential pressure switch 7 and the gas pressure transmitter 8 are all communicated with the distributed control system (DCS system for short).

On the pipeline between the gas cooler 5 and the second gas control valve 6, an air supply pipeline 10 is set, and a third gas control valve 11 is set on the gas supply pipeline 10, and the third gas control valve 11 is connected to the DCS system in communication; The function of the third gas control valve 11 is to supply gas to the pipeline at the rear end of the air-cooled Roots pump 2 when the liquid ring vacuum pump 3 is shut down, so as to prevent the liquid in the liquid ring vacuum pump 3 from flowing back into the air when the second gas control valve 6 fails. Cold roots pump 2.

As shown in Figure 1, in the air-cooled Roots liquid loop closed vacuum system, a gas-liquid separator 12 can also be arranged, and a liquid level transmitter 13 is arranged on the side of the gas-liquid separator 12, and a liquid level transmitter 13 is installed on the side of the gas-liquid separator 12. An overflow pipeline 14 is set in the middle of the gas-liquid separator 12, a liquid replenishment pipeline 15 is set on the upper part of the gas-liquid separator 12, and a liquid replenishment valve 16 is set on the liquid replenishment pipeline 15, and the liquid level transmitter 13 and the liquid replenishment valve 16 are connected to the DCS system by communication. The liquid level transmitter 13 can use a magnetic flap liquid level gauge to measure the liquid level through the movement of the magnetic float, or can use a double flange liquid level transmitter to measure the liquid level through the pressure difference.

The working process of the utility model air-cooled Roots liquid-loop closed vacuum system applied to the condenser of the power plant is as follows:

The system gas of -0.098MPa～-0.092MPa comes in from the input end of the main gas pipeline 1, and is first compressed to -0.09MPa～-0.085MPa by the air-cooled Roots pump 2, and the pressurized gas is cooled by the gas cooler 5 Finally, a part of the gas flows back to the air-cooled Roots pump 2 through the return pipeline 9 for cooling to prevent the overheating of the air-cooled Roots pump 2, and the remaining gas enters the liquid ring vacuum pump 3 through the main gas pipeline 1 and is further pressurized to normal pressure. The compressed gas and the heated working fluid enter the gas-liquid separator 12 together. After the gas-liquid separation, the gas is discharged directly, and the working fluid enters the liquid cooler through the liquid pipeline to cool to normal temperature, and then enters the liquid ring vacuum pump 3 again. for recycling.

When the post-valve pressure of the first gas control valve 4 is higher than the pre-valve pressure within 3KPa, the gas differential pressure switch 7 transmits a signal to the DCS system, and the DCS system makes the first gas control valve 4 open for vacuuming; when the first gas control valve When the pressure behind the valve 4 is 3KPa higher than the pressure before the valve, the gas differential pressure switch 7 transmits a signal to the DCS system, and the DCS system closes the first gas control valve 4 to prevent gas backflow.

When the vacuum degree at the gas pressure transmitter 8 reaches -0.09MPa～-0.092MPa, the gas pressure transmitter 8 transmits a signal to the DCS system, and the DCS system starts the air-cooled Roots pump 2 for vacuuming; when the gas pressure When the vacuum at the transmitter 8 is lower than -0.09MPa, the gas pressure transmitter 8 transmits a signal to the DCS system, and the DCS system stops the air-cooled Roots pump 2 to prevent motor overload.

When the liquid ring vacuum pump 3 is shut down, the DCS system opens the third gas control valve 11 to supply air, and closes the second gas control valve 6 to prevent the working fluid in the liquid ring vacuum pump 3 from flowing back and damaging the air-cooled Roots pump 2 .

When the liquid level in the gas-liquid separator 12 is higher than 50 mm above the horizontal centerline of the separator, the liquid is automatically discharged through the overflow pipeline 14 until the liquid level drops to the horizontal centerline of the separator; when the gas-liquid separator When the liquid level in 12 is lower than 50mm below the horizontal centerline of the separator, the liquid level transmitter 13 transmits a signal to the DCS system, and the DCS system opens the replenishment valve 16 for replenishment until the liquid level rises to the horizontal centerline of the separator, and then Make the replenishment valve 16 close.

In a word, the utility model has high operating efficiency, can save more than 70% of electricity and water of more than 40% on average, can greatly reduce the energy consumption of enterprises, improve the working environment, and improve work efficiency. In addition, it has high ultimate vacuum, low failure rate, It can be widely used in power plant condenser systems due to the advantages of small footprint.

Although the embodiments have described the utility model in detail, those skilled in the art should understand that the technical solutions of the utility model can still be modified and equivalently replaced, which should be covered by the claims of the utility model.

Claims (4)

1. an air cooling Roots pendular ring closed vacuum system, be included on main gas line (1) and air cooling Roots pump (2) and liquid-ring vacuum pump (3) are set, it is characterized in that, between main gas line (1) input end with liquid-ring vacuum pump (3) input end, sequential series is connected the first gas control valve (4), air cooling Roots pump (2), gas cooler (5) and the second gas control valve (6), the pipeline of described first gas control valve (4) front end arranges gas differential pressure switch (7), pipeline between described first gas control valve (4) and described air cooling Roots pump (2) arranges gas pressure transmitter (8), return line (9) is set between described air cooling Roots pump (2) and described gas cooler (5).

2. air cooling Roots pendular ring closed vacuum system according to claim 1, it is characterized in that, described first gas control valve (4), the second gas control valve (6), gas differential pressure switch (7) and gas pressure transmitter (8) are all called for short DCS system with Distributed Control System and communicate to connect.

3. air cooling Roots pendular ring closed vacuum system according to claim 1 and 2, it is characterized in that, pipeline between described gas cooler (5) and the second gas control valve (6) is arranged tonifying Qi pipeline (10), described tonifying Qi pipeline (10) arranges the 3rd gas control valve (11).

4. air cooling Roots pendular ring closed vacuum system according to claim 3, is characterized in that, described 3rd gas control valve (11) and DCS system communicate to connect.