Laboratory gas supply system engineering

Sailaite Technology undertakes laboratory centralized gas supply system, laboratory gas supply system engineering, and laboratory centralized gas supply installation services

Many devices in the laboratory use various gas supplies and exhaust gases. How to safely and conveniently solve the problem of air supply and exhaust has always been one of the problems that troubles laboratory staff. The traditional laboratory gas supply method is to place gas cylinders next to the equipment and hazardous gas cylinders in the gas cylinder cabinet. The exhaust gas is directly discharged into the laboratory or discharged through a simple pipeline to the window. In the development process of laboratories, with the increase of laboratory equipment, laboratories are often covered with various pipelines and steel cylinders. This treatment poses significant security risks and is not aesthetically pleasing. Therefore, the safe, continuous, and stable operation of the laboratory requires us to consider how to supply these gases to the analytical instruments placed in each laboratory.

Considering safety and efficiency factors, without considering economic factors, a centralized gas supply system in the laboratory is an excellent approach. And become a reliable and continuous supply source for high-purity gas used in laboratory equipment today, with gas passing through pipeline systems.

1. Composition of Laboratory Gas Supply System Engineering

The centralized gas supply system generally consists of gas cylinder cabinets, high-pressure steel cylinders, gas switching devices, pressure reducing devices, valves, pipelines, filters, alarms, terminal regulating valves, and other components.

Display diagram of each component

2. Characteristics of Laboratory Gas Supply System Engineering：

(1) Improved security

The inflation pressure of bottled gas is generally greater than or equal to 14MPa/cm2. Centralized gas supply can reduce the system pressure as needed and is far away from the experimental area, improving the safety of use. In addition, centralized gas supply can place the air compressor in the gas supply room to reduce the safety hazards caused by electric sparks generated by the compressor and avoid noise interference in the laboratory.

(2) Ensure gas purity

The carrier gas is transported to the instrument through a large storage tank (hydraulic) and a conveying pipeline. A one-way valve is installed at the outlet of the storage tank to avoid the mixing of air or moisture when replacing the tank. In addition, a pressure relief switch ball valve can be installed after the high-pressure section to discharge excess air or moisture and ensure the purity of the gas.

(3) Good voltage stabilization effect

Centralized gas supply can achieve better pressure stabilization by using two-stage or multi-stage pressure reduction methods. For example, after the second level pressure reduction of the system, coupled with the pressure regulating device inside the instrument, it can be said to be a third level pressure stabilization. After the first level pressure reduction of the gas source, the main pipeline maintains a high pressure for long-distance pipeline transportation. A second level low-pressure pressure reducing valve is used at the front end of the instrument to adjust the pressure to the working range of the instrument. After the pressure adjustment inside the instrument, the gas entering the instrument can ensure that it meets the requirements for instrument use.

(4) Improving the working environment

The cancellation of gas supply sources such as steel cylinders and air compressors in the laboratory reduces the footprint, facilitates the layout of laboratory equipment and facilities, and avoids confusion and inconvenience caused by being in the same place as laboratory operators.

(5) Reduce operating costs

The centralized gas supply system can use liquid storage tanks with large storage capacity to supply gas, which can greatly save procurement costs, reduce the frequency of replacing gas cylinders, save labor costs, reduce the labor intensity of maintenance personnel, and facilitate management, maintenance, and upkeep.

(6) Continuous and timely

The centralized gas supply system adopts a manual, semi-automatic, or fully automatic switching system. Each gas supply source is usually in a state of one on and one backup, and the local or overall gas pressure and flow can be adjusted according to the working conditions of the instrument. This can ensure the stability and continuity of the gas flow and pressure used by the instrument, and also ensure that the value transmission does not change.

(7) Scalability and flexibility

Gas connection points and expandable points can be reserved on the centralized gas supply pipeline, and control switches or plugs can be installed for easy expansion. All instruments that use gas are equipped with control valves at the front end. Therefore, new gas endpoints can be expanded without affecting the normal operation of other instruments.

3. Schematic diagram of laboratory pneumatic system

4. Preparation for the construction of laboratory pneumatic system

(1) Construction personnel should carefully check the construction design drawings before construction, organize construction according to the technical requirements of the drawings, strictly implement relevant regulations, specifications, and quality inspection and evaluation standards, promptly handle design change negotiations with the design personnel for any changes, and not arbitrarily change the design drawings. Detailed construction technical disclosure should be carried out at the construction site.

(2) After entering the construction site, the construction team shall follow the unified arrangement of the contracting party, protect various finished products on site, arrange temporary electricity, and carefully inspect electrical equipment, distribution boxes, and wires.

(3) Materials and equipment should have factory certificates of conformity, material certification documents, and inspection reports. After entering the site, quality, specifications, quantity, and other verification work should be carried out in conjunction with the contracting party, and a written inspection record should be formed.

Construction site map

5. Installation and laying of gas pipelines

5.1 The 316L stainless steel pipeline used in this project is connected by argon arc welding.

5.2 Key points of pipeline design and planning:

(1) The outlet of the gas cylinder valve adopts the GB standard external thread form (G5/8 "). In order to facilitate the connection between the pipeline system and the gas cylinder, a conversion joint (gas cylinder joint) should be provided from the outlet of the gas cylinder valve to the pipeline system.

(2) In order to facilitate the replacement of gas cylinders during use, a high-pressure spiral tube with high pressure resistance should be installed between the cylinder joint and the regulating valve.

(3) Due to the gas pressure inside the gas cylinder being around 20-25MPa, the pressure at the point of use is relatively low, resulting in changes in gas pressure and significant differences in values. Therefore, a primary pressure reducing valve should be installed at the outlet of the gas cylinder, and a secondary pressure reducing valve should be installed in front of the gas usage point.

(4) Each gas system should be equipped with a device that can quickly cut off the gas supply in emergency situations. In order to ensure the convenience and speed of the switch system, the on/off valve of this project adopts a ball valve.

(5) In order to prevent external air from entering the pipeline system during bottle replacement, a ball valve should be installed. The ball valve should be connected to the exhaust pipe, which should be reliably connected to the atmosphere. The exhaust pipes for flammable and combustible gases should be set independently, and explosion-proof check valves should be installed at the outlet of the exhaust pipe to prevent backfire.

(6) In hydrogen and acetylene systems, in order to prevent backfire, explosion-proof check valves should be installed at the low-pressure end of the system (after the primary pressure reducing valve).

(7) At the outlet of the gas pipeline system, a ball valve should be installed for easy switching of the system.

(8) In order to ensure the purity of the gas and the airtightness of the pipeline system, all pipelines are made of 316L stainless steel and the inner surface is treated with BA.

(9) In order to facilitate maintenance and replacement of valve components, while ensuring the airtightness of the system, the connection between the pipeline and valve components should be made using high-pressure double sleeve joints.

(10) Pipe fittings (clamps) should be made of high temperature resistant materials, which are required to be sturdy, lightweight, and durable.

(11) The control panel of the regulating valve, the control panel of the outlet point, and all pipelines should be labeled with gas composition.

Pipe fitting display diagram

6. Security technical requirements

The safety technology of gas pipeline design should comply with relevant design specifications and the following requirements

(1) Gas pipelines, conductive lines, and cables should not be laid simultaneously in the same rack.

(2) All pressure reducing valves must be equipped with exhaust pipelines to the outside of the gas storage area. The exhaust pipes for oxidizing gases cannot be connected together.

(3) The pipeline system should be equipped with pressure regulating devices, which include various valves (regulating valves, globe valves, ball valves, etc.) to achieve the functions of opening, closing, and regulating gas. Set up a separate valve (ball valve or needle valve) to control the gas outlet on the workbench.

(4) Various gas pipelines should have clear indication signs. The label of the safety pressure reducing valve should indicate the pressure release level.

(5) Laboratories using hydrogen and flammable gases should be equipped with alarm devices and gas flashback arresters should be installed on the venting pipelines.

(6) The area where hydrogen gas cylinders are stored should have measures for not less than three air changes per hour.

(7) Accessories such as bottle valves, connecting screws, and pressure reducing valves should not have any dangerous situations such as leakage, slippage, or looseness. Various pressure gauges should generally not be mixed.

Post construction rendering