Automatic nitrogen cut-in system

Abstract

The utility model belongs to the technical field of gas supply, and particularly relates to an automatic nitrogen cut-in system which comprises an automatic cut-in loop and a manual cut-in loop which are both arranged on a nitrogen main pipe line. Wherein a first gate valve, a first electromagnetic valve, a second electromagnetic valve, a second gate valve, a first check valve and a second check valve are sequentially connected in the automatic cut-in loop and then connected with a user, a standby bleeder is arranged between the first gate valve and the first electromagnetic valve, and a sixth gate valve is arranged on the standby bleeder. An automatic bleeder is arranged between the first electromagnetic valve and the second electromagnetic valve; the manual cut-in loop is communicated with a valve front pipeline of a first check valve in the automatic cut-in loop, the third gate valve and the fourth gate valve are communicated with a relief port through a manual relief pipe, and a seventh gate valve is arranged on the manual relief pipe. Compared with the prior art, the automatic switching-in device has the beneficial effects that the automatic switching-in speed of the second air source is high, and the air source is stable.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas supply security, and in particular relates to a nitrogen automatic cutting-in system. Background Art

[0002] Instrument-purified compressed air is a common power medium and plays an important role in industrial production. Many instruments rely on instrument-purified compressed air to work, such as pressure gauges and regulating valves. Without the supply of instrument-purified compressed air, many instruments and valves will not be able to work properly, thus affecting the control and monitoring of the production process. Therefore, in industrial production, instrument-purified compressed air is an indispensable and important link.

[0003] Relevant specifications give requirements for safe use of gas: gas source devices should be equipped with backup gas sources. Backup gas sources can be backup compressor units, gas storage tanks or second gas sources. For large devices or gas supply systems with high reliability, in addition to backup compressors and gas storage tanks, a second gas source can also be set up. The second gas source should be put into operation automatically. When the second gas source is running, there should be sound and light signal display in the control room.

[0004] The Chinese utility model patent with application number 201721121127.4 discloses an LNG unloading skid device with a cryogenic centrifugal pump and a pressurized gasifier, including a liquid unloading pipeline, a gas phase pipeline, a pressurized gas phase pipeline, a safety release pipeline, and a nitrogen purge protection pipeline, and also includes a structural frame, on which the liquid unloading pipeline, the gas phase pipeline and the pressurized gas phase pipeline are respectively installed through cold-insulating pipe supports, and the structural frame is also installed with a safety release pipeline, a nitrogen purge protection pipeline and an instrument air pipeline through a bracket; the LNG unloading skid body and the pressurized gasifier are installed on a loading island together, and all functional pipelines and control systems are integrated in the LNG unloading skid, so that the entire LNG unloading skid has a compact structure, thereby greatly improving the unloading capacity of the LNG liquefaction plant or storage station, and achieving a higher gasification level and a larger supply capacity.

[0005] In coking plants, where purified compressed air and nitrogen for instruments need to be switched frequently, standby units and gas storage tanks are required to ensure safe use of gas. However, the standby units have the disadvantages of slow startup speed and the gas storage tanks have the disadvantages of large capacity. At present, there is no corresponding automatic cut-in system to improve the automation level of the switching operation. Utility Model Content

[0006] The utility model aims to provide a nitrogen automatic cut-in system, which overcomes the shortcomings of the prior art and adopts two modes of automatic cut-in and manual cut-in. Automatic cut-in is adopted under normal working conditions. When the automatic cut-in fails, manual cut-in can be used to ensure safe gas use. The second gas source automatically cuts in at a fast speed and the gas source is stable.

[0007] To achieve the above purpose, the utility model is implemented through the following technical solutions:

[0008] A nitrogen automatic cut-in system, a nitrogen main line and a purified compressed air pipeline for instruments, characterized in that it comprises an automatic cut-in circuit and a manual cut-in circuit, both of which are arranged on the nitrogen main line, wherein the automatic cut-in circuit is sequentially connected with a first gate valve, a first solenoid valve, a second solenoid valve, a second gate valve, and a first check valve, and a user is connected after the first check valve, a spare discharge pipe is arranged between the first gate valve and the first solenoid valve, a sixth gate valve is arranged on the spare discharge pipe, an automatic discharge pipe is arranged between the first solenoid valve and the second solenoid valve, and a third solenoid valve is arranged on the automatic discharge pipe;

[0009] The manual cut-in loop is connected with an eighth gate valve, a third gate valve, a fourth gate valve, and a ninth gate valve in sequence, the outlet of the ninth gate valve is connected with the valve front pipeline of the first check valve in the automatic cut-in loop, the third gate valve and the fourth gate valve are connected with the venting port through a manual venting pipe, and the manual venting pipe is provided with a seventh gate valve;

[0010] The outlet of the first check valve is connected to the purified compressed air pipeline for instruments through a combined pipeline; a fifth gate valve and a second check valve are provided at the front end of the combined pipeline.

[0011] The first gate valve, the second gate valve, the fifth gate valve, the first check valve, the second check valve, the eighth gate valve and the ninth gate valve are normally open valves; the first solenoid valve, the second solenoid valve, the third gate valve, the fourth gate valve, the sixth gate valve, the seventh gate valve and the third solenoid valve are normally closed valves.

[0012] The first gate valve, the first solenoid valve and the third solenoid valve constitute an automatic purge and release circuit.

[0013] The first gate valve and the sixth gate valve constitute a standby purge and release circuit.

[0014] The eighth gate valve, the third gate valve and the seventh gate valve constitute a manual purge and release circuit.

[0015] The diameter of the vent pipe is equal to or smaller than the diameter of the nitrogen main line.

[0016] Any of the solenoid valves described may be replaced with a pneumatic solenoid valve.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] 1) The utility model can realize the automatic cutting-in speed of the second gas source at a high speed and a stable gas source, thereby improving production efficiency and energy utilization efficiency, and plays a positive role in creating good economic benefits.

[0019] 2) The utility model is equipped with two modes of automatic cut-in and manual cut-in. Automatic cut-in is used under normal working conditions. When the automatic cut-in fails, manual cut-in can also be used to ensure safe use of gas and smooth safe production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a process flow chart of an embodiment of the utility model.

[0021] In the figure: 1-first gate valve, 2-first solenoid valve, 3-second solenoid valve, 4-second gate valve, 5-first check valve, 6-third gate valve, 7-fourth gate valve, 8-fifth gate valve, 9-second check valve, 10-sixth gate valve, 11-seventh gate valve, 12-third solenoid valve, 13-eighth gate valve, 14-ninth gate valve, 15-nitrogen main line, 16-instrument purified compressed air pipeline, 17-automatic cut-in loop, 18-manual cut-in loop, 19-spare bleed pipe, 20-automatic bleed pipe, 21-manual bleed pipe, 22-merged pipeline. DETAILED DESCRIPTION

[0022] The technical solution of the present utility model will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present utility model, rather than all of the embodiments.

[0023] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the specific embodiments required to be used in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some implementation methods of the utility model. For ordinary technicians in this field, other specific embodiments can be obtained based on these specific embodiments without paying creative work.

[0024] The components of the embodiments of the present invention generally described and shown in the specific embodiments herein can be arranged and designed in countless different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the utility model claimed, but only represents the selected embodiments of the utility model.

[0025] See Figure 1, is a process flow chart of an embodiment of a nitrogen automatic cut-in system of the utility model, which is arranged between the nitrogen main line 15 and the purified compressed air pipeline 16 for instruments, including an automatic cut-in loop 17 and a manual cut-in loop 18, the automatic cut-in loop 17 and the manual cut-in loop 18 are both arranged on the nitrogen main line 15, wherein the automatic cut-in loop 17 is connected in sequence to the first gate valve 1, the first solenoid valve 2, the second solenoid valve 3, the second gate valve 4, and the first check valve 5, and the user is connected after the first check valve 5, a spare vent pipe 19 is arranged between the first gate valve 1 and the first solenoid valve 2, and a sixth gate valve 10 is arranged on the spare vent pipe 19, the first solenoid valve 2 An automatic relief pipe 20 is provided between the second solenoid valve 3 and the automatic relief pipe 20, and a third solenoid valve 12 is provided on the automatic relief pipe 20; the eighth gate valve 13, the third gate valve 6, the fourth gate valve 7 and the ninth gate valve 14 are connected in sequence in the manual cut-in loop 18, the outlet of the ninth gate valve 14 is connected to the valve front pipeline of the first check valve 5 in the automatic cut-in loop, the third gate valve 6 and the fourth gate valve 7 are connected to the relief port through a manual relief pipe 21, and a seventh gate valve 11 is provided on the manual relief pipe 21; the outlet of the first check valve 5 is connected to the purified compressed air pipeline 16 for instruments through a merging pipeline 22; a fifth gate valve 8 and a second check valve 9 are provided at the front end of the merging pipeline.

[0026] Qualified instrument-purified compressed air is supplied to instrument-purified compressed air users after passing through the fifth gate valve 8 and the second check valve 9. When the instrument-purified compressed air fails and cannot meet the user's demand, it is necessary to introduce a second air source (nitrogen) to ensure the use of instrument-purified compressed air users.

[0027] Under normal working conditions, nitrogen enters the circuit automatically, and passes through the first gate valve 1, the first solenoid valve 2, and the third solenoid valve 12 in sequence to purge and release unclean gas in the pipeline. Then the third solenoid valve 12 is closed, and the nitrogen passes through the first gate valve 1, the first solenoid valve 2, the second solenoid valve 3, the second gate valve 4, and the first check valve 5 in sequence, and then is merged into the instrument compressed air main pipe to supply users.

[0028] During operation, the first gate valve 1, the second gate valve 2, the fifth gate valve 8, the first check valve 5, the second check valve 9, the eighth gate valve 13 and the ninth gate valve 14 are all normally open valves; the first solenoid valve 2, the second solenoid valve 3, the third gate valve 6, the fourth gate valve 7, the sixth gate valve 10, the seventh gate valve 11 and the third solenoid valve 12 are all normally closed valves.

[0029] The first gate valve 1, the first solenoid valve 2, and the third solenoid valve 3 form an automatic purge and release circuit. The first gate valve 1 and the sixth gate valve 10 form a backup purge and release circuit. The pipeline of the sixth gate valve 10 is a release backup pipeline for the pipeline of the third solenoid valve 12. When the pipeline of the third solenoid valve 12 cannot be released, the pipeline of the sixth gate valve 10 can be manually cut in for purge and release.

[0030] The eighth gate valve 13, the third gate valve 6, and the seventh gate valve 11 form a manual purge and release circuit. When the automatic cut-in cannot be completed under normal working conditions, nitrogen needs to be manually cut into the pipeline. Nitrogen passes through the eighth gate valve 13, the third gate valve 6, the seventh gate valve 11 in turn, and purges and releases the unclean gas in the pipeline. After that, the seventh gate valve 11 is closed, and the nitrogen passes through the eighth gate valve 13, the third gate valve 6, the fourth gate valve 7, the ninth gate valve 14, and the first check valve 5 in turn, and then is merged into the instrument compressed air main pipe to supply users. In the scheme, the valve pair of the eighth gate valve 13 and the third gate valve 6, and the valve pair composed of the fourth gate valve 7 and the ninth gate valve 14 play the role of redundant design, preventing the failure of a single valve to safely and quickly carry out emergency treatment, and avoiding the impact on safe production.

[0031] The maintenance operation of the normally closed valve when it fails is as follows: when the first solenoid valve 2 fails, close the first gate valve 1, the second solenoid valve 3, the sixth gate valve 10, and the third solenoid valve 12, and then repair the first solenoid valve 2; when the second solenoid valve 3 fails, close the first solenoid valve 2, the second gate valve 4, and the third solenoid valve 12, and then repair the second solenoid valve 3; when the third gate valve 6 fails, close the eighth gate valve 13, the fourth gate valve 7, and the seventh gate valve 11, and then repair the third gate valve 6; when the fourth gate valve 7 fails, close the third gate valve 6, the seventh gate valve 12, and then repair the third gate valve 6. 11, after the ninth gate valve 14, inspect the fourth gate valve 7; when the sixth gate valve 10 fails, close the first gate valve 1, the first solenoid valve 2, the seventh gate valve 11, and the third solenoid valve 12, and then inspect the sixth gate valve 10; when the seventh gate valve 11 fails, close the third gate valve 6, the fourth gate valve 7, the sixth gate valve 10, and the third solenoid valve 12, and then inspect the seventh gate valve 11; when the third solenoid valve 12 fails, close the first solenoid valve 2, the second solenoid valve 3, the sixth gate valve 10, and the seventh gate valve 11, and then inspect the third solenoid valve 12.

[0032] The automatic purge and release circuit, the standby purge and release circuit, and the manual purge and release circuit are all of equal diameter to or smaller than the diameter of the nitrogen main line 15 to ensure the release pressure.

[0033] Any of the solenoid valves can also be replaced by a pneumatic solenoid valve, and the automatic cutting-in purpose of the utility model can be achieved.

[0034] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nitrogen automatic cut-in system, a nitrogen main line and a purified compressed air pipeline for instruments, characterized in that: It includes an automatic cut-in circuit and a manual cut-in circuit, both of which are arranged on the nitrogen main line, wherein the automatic cut-in circuit is connected with a first gate valve, a first solenoid valve, a second solenoid valve, a second gate valve, and a first check valve in sequence, and the user is connected after the first check valve, a spare discharge pipe is arranged between the first gate valve and the first solenoid valve, and a sixth gate valve is arranged on the spare discharge pipe, an automatic discharge pipe is arranged between the first solenoid valve and the second solenoid valve, and a third solenoid valve is arranged on the automatic discharge pipe; The manual cut-in loop is connected with an eighth gate valve, a third gate valve, a fourth gate valve, and a ninth gate valve in sequence, the outlet of the ninth gate valve is connected with the valve front pipeline of the first check valve in the automatic cut-in loop, the third gate valve and the fourth gate valve are connected with the venting port through a manual venting pipe, and the manual venting pipe is provided with a seventh gate valve; The outlet of the first check valve is connected to the purified compressed air pipeline for instruments through a combined pipeline; a fifth gate valve and a second check valve are provided at the front end of the combined pipeline.

2. The nitrogen automatic cut-in system according to claim 1, characterized in that: The first gate valve, the second gate valve, the fifth gate valve, the first check valve, the second check valve, the eighth gate valve and the ninth gate valve are normally open valves; the first solenoid valve, the second solenoid valve, the third gate valve, the fourth gate valve, the sixth gate valve, the seventh gate valve and the third solenoid valve are normally closed valves.

3. The nitrogen automatic cut-in system according to claim 1, characterized in that: The first gate valve, the first solenoid valve and the third solenoid valve constitute an automatic purge and release circuit.

4. The nitrogen automatic cut-in system according to claim 1, characterized in that: The first gate valve and the sixth gate valve constitute a standby purge and release circuit.

5. The nitrogen automatic cut-in system according to claim 1, characterized in that: The eighth gate valve, the third gate valve and the seventh gate valve constitute a manual purge and release circuit.

6. The nitrogen automatic cut-in system according to claim 1, characterized in that: The diameter of the vent pipe is equal to or smaller than the diameter of the nitrogen main line.

7. The nitrogen automatic cut-in system according to claim 1, characterized in that: Any of the solenoid valves described may be replaced with a pneumatic solenoid valve.

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