Automatic nitrogen supplementing system for instrument air of air compressor

Abstract

The utility model discloses an automatic nitrogen supplementing system for air compressor instrument air, which comprises an air compressor, an instrument air regulating valve, a first check valve and an instrument air pressure transmitter are sequentially arranged on an instrument air pipeline at an outlet of the air compressor, and the automatic nitrogen supplementing system comprises a nitrogen making machine. A nitrogen regulating valve and a nitrogen pressure transmitter are sequentially arranged on the nitrogen pipeline at the outlet of the nitrogen making machine; the nitrogen pipeline between the nitrogen regulating valve and the nitrogen pressure transmitter is communicated with the instrument air pipeline, and a second check valve and a nitrogen supplementing valve are sequentially arranged on the nitrogen pipeline between the nitrogen regulating valve and the nitrogen pressure transmitter; the instrument air pressure transmitter is electrically connected with the signal input end of the PLC, and the signal output end of the PLC is electrically connected with the nitrogen supplementing valve. Interlocking is arranged between the nitrogen system and the instrument air system, automatic supplementation of the nitrogen system to instrument air is achieved through the pressure difference of the two kinds of gas, and stable operation of all pneumatic valves is guaranteed.

Description

Technical Field

[0001] The utility model relates to the field of chemical production equipment, in particular to an automatic nitrogen replenishing system for air compressor instrument air. Background Art

[0002] In the chemical production process, with the continuous improvement of the automation level of production technology, the number of automatic valves used in the equipment has gradually increased, especially the number of pneumatic control valves used and the increase in the places of use are the most prominent.

[0003] Pneumatic valves operate by using instrument air to control the opening and closing of valves or adjust valve opening to achieve fluid control. The proper functioning of pneumatic valves depends heavily on stable and sufficient instrument air pressure. If the instrument air pressure is too low, the pneumatic valve may not receive sufficient power to open or close the valve, resulting in malfunction or sluggish valve operation. Conversely, while excessive pressure provides greater driving force, it may also cause the valve to operate too violently, accelerating mechanical wear or damaging sealing performance.

[0004] During the production process, factories usually use air compressors to produce instrument air to supply pneumatic valves. Air compressors are dynamic equipment and are prone to failure in equipment and electrical appliances. Compressors often fail and automatically stop, resulting in insufficient air pressure for factory instruments. Pneumatic valves cannot obtain sufficient power to drive the valves open or closed, causing valve failure or slow operation, which often leads to emergency shutdown of the device system. Especially in the production process of hazardous chemicals, emergency shutdown of the system can easily lead to safety accidents and affect normal production. Utility Model Content

[0005] The utility model provides an automatic nitrogen replenishment system for air compressor instrument air. During the operation of the device, when the instrument air pressure is insufficient, nitrogen can be automatically replenished to the instrument air system through the control system to ensure the stable operation of each pneumatic valve and guarantee normal production.

[0006] To achieve its purpose, the utility model adopts the following technical solutions:

[0007] An automatic nitrogen replenishment system for instrument air of an air compressor comprises an air compressor, wherein an instrument air regulating valve, a first check valve, and an instrument air pressure transmitter are sequentially provided on an instrument air pipeline at an outlet of the air compressor; the automatic nitrogen replenishment system comprises a nitrogen generator, wherein a nitrogen regulating valve and a nitrogen pressure transmitter are sequentially provided on a nitrogen pipeline at an outlet of the nitrogen generator; the nitrogen pipeline between the nitrogen regulating valve and the nitrogen pressure transmitter is connected to the instrument air pipeline, and a second check valve and a nitrogen replenishment valve are sequentially provided on the nitrogen pipeline between the nitrogen regulating valve and the nitrogen pressure transmitter; the instrument air pressure transmitter is electrically connected to a signal input terminal of a programmable logic controller (PLC), and a signal output terminal of the PLC is electrically connected to the nitrogen replenishment valve.

[0008] Furthermore, the connections of the instrument air pipeline and the nitrogen pipeline are both connected using pipeline flanges.

[0009] Furthermore, metal spiral wound gaskets are used at all pipe flange connections.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The utility model provides an automatic nitrogen replenishment system for air compressor instrument air. By setting an interlock between the nitrogen system and the instrument air system, the interlock is controlled by a PLC programmable controller using the pressure difference between the two gases, thereby realizing automatic replenishment of the instrument air by the nitrogen system, ensuring stable operation of each pneumatic valve and guaranteeing normal production. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic structural diagram of the nitrogen automatic replenishment system of the present utility model;

[0013] In the figure: 1-nitrogen generator; 2-nitrogen regulating valve; 3-nitrogen pipeline; 4-nitrogen pressure transmitter; 5-air compressor; 6-instrument air regulating valve; 7-first check valve; 8-instrument air pipeline; 9-instrument air pressure transmitter; 10-second check valve; 11-nitrogen replenishing valve; 12-PLC programmable controller. DETAILED DESCRIPTION

[0014] The present invention will be further described below with reference to the accompanying drawings:

[0015] like Figure 1 As shown, the utility model is an automatic nitrogen replenishment system for air compressor instrument air, comprising an air compressor 5, an instrument air regulating valve 6, a first check valve 7 and an instrument air pressure transmitter 9 are sequentially provided on the instrument air pipeline 8 at the outlet of the air compressor 5.

[0016] The automatic nitrogen replenishment system includes a nitrogen generator 1. A nitrogen regulating valve 2 and a nitrogen pressure transmitter 4 are sequentially installed on the nitrogen pipeline 3 at the outlet of the nitrogen generator 1 to facilitate nitrogen pressure monitoring. The nitrogen pipeline 3 between the nitrogen regulating valve 2 and the nitrogen pressure transmitter 4 is connected to an instrument air pipeline 8. A second check valve 10 and a nitrogen replenishment valve 11 are also sequentially installed on the nitrogen pipeline 3 between the nitrogen regulating valve 2 and the nitrogen pressure transmitter 4. The instrument air pipeline 8 and the nitrogen pipeline 3 are both connected using pipe flanges, and metal spiral wound gaskets are used at both pipe flange connections.

[0017] The instrument air pressure transmitter 9 is electrically connected to a signal input terminal of a PLC programmable controller 12 , and a signal output terminal of the PLC programmable controller 12 is electrically connected to a nitrogen replenishment valve 11 .

[0018] During operation, all pipes and fittings in the system are pressure-tested at 1.0 MPa to prevent leaks during production. The instrument air generated by air compressor 5 is pressure-regulated by instrument air control valve 6 before being delivered to the pneumatic valves in the system for use as a power source. A first check valve 7 is installed in the outlet pipe of air compressor 5 to prevent backflow of instrument air into compressor 5 during shutdown. An instrument air pressure transmitter 9 is installed at the outlet of air compressor 5, typically set based on the air source pressure parameters required by the valves.

[0019] In the nitrogen automatic replenishment system, the nitrogen pipeline 3 between the nitrogen regulating valve 2 and the nitrogen pressure transmitter 4 is connected to the instrument air pipeline 8, and the nitrogen pipeline 3 between the nitrogen regulating valve 2 and the nitrogen pressure transmitter 4 is sequentially provided with a second check valve 10 and a nitrogen replenishment valve 11; since nitrogen is a protective gas, the second check valve 10 is provided to prevent the instrument air from flowing back into the nitrogen system during the nitrogen replenishment process, thereby rendering the nitrogen protective property ineffective.

[0020] An interlock is set up between the instrument air pressure transmitter 9, the PLC programmable controller 12, and the nitrogen replenishment valve 11. The interlock logic is: when the instrument air pressure transmitter 9 displays a pressure ≤0.4Mpa, the nitrogen replenishment valve 11 automatically opens to replenish the instrument air pipeline; when the instrument air pressure transmitter 9 displays a pressure ≥0.6Mpa, the nitrogen replenishment valve 11 automatically closes. By setting an interlock with the PLC programmable controller 12, the nitrogen system can automatically replenish the instrument air. After the nitrogen system and the instrument air system are running stably, the interlock is activated through the PLC programmable controller 12, and the replenishment is achieved by utilizing the pressure difference between the two gases. In the event that the air compressor 5 fails or the instrument air pressure is too low due to other reasons, nitrogen can be used to replenish the instrument air in a timely manner.

Claims

1. An automatic nitrogen replenishment system for air compressor instrument air, comprising an air compressor (5), an instrument air regulating valve (6), a first check valve (7) and an instrument air pressure transmitter (9) being sequentially provided on an instrument air pipe (8) at the outlet of the air compressor (5), characterized in that: The nitrogen automatic replenishment system comprises a nitrogen generator (1), wherein a nitrogen regulating valve (2) and a nitrogen pressure transmitter (4) are sequentially provided on a nitrogen pipeline (3) at an outlet of the nitrogen generator (1); the nitrogen pipeline (3) between the nitrogen regulating valve (2) and the nitrogen pressure transmitter (4) is connected to an instrument air pipeline (8), and a second check valve (10) and a nitrogen replenishment valve (11) are sequentially provided on the nitrogen pipeline (3) between the nitrogen regulating valve (2) and the nitrogen pressure transmitter (4); The instrument air pressure transmitter (9) is electrically connected to a signal input end of a PLC programmable controller (12), and a signal output end of the PLC programmable controller (12) is electrically connected to a nitrogen replenishment valve (11).

2. The automatic nitrogen replenishment system for air compressor instrument air according to claim 1, characterized in that: The instrument air pipeline (8) and the nitrogen pipeline (3) are both connected using pipeline flanges.

3. The automatic nitrogen replenishment system for air compressor instrument air according to claim 2, characterized in that: Metal spiral wound gaskets are used at the pipe flange connections.

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