1. Program background

In China's food freezing system, more than 80% of cold storage uses ammonia as a refrigerant. With the development and progress of science and technology, the establishment and improvement of various normative systems, the requirements for the safety of food cold storage are getting stricter and stricter. The safety of the ammonia refrigeration system of food cold storage has also become a key issue in cold storage engineering. In order to prevent and reduce the harm of ammonia leakage and protect the safety of personal and property, more attention should be paid to the design of cold storage.How to reasonably design an automatic alarm system for ammonia leakage in ammonia refrigeration room to effectively ensure the operation safety of ammonia refrigeration room

Ammonia leakage is a special hidden danger in ammonia cold storage. Once an ammonia leak occurs, the first to bear the brunt is the fire. When the concentration of ammonia reaches 15.5% to 27%, open flames will cause explosion. Because the toxicity of ammonia itself is harmful to the human body, ammonia leakage can also cause convulsions, fainting, and even suffocation.

There are many reasons for the leakage of cold storage ammonia, which generally include the aging of equipment, personnel operating errors, and management negligence. With the increase of the service life, the equipment will have different degrees of aging. The valve is aging and the axis is loose, which reduces the airtightness, which leads to ammonia leakage. The welding of the pipes in the cold storage may also cause aging and cracks, or the pipes may be corroded and the flange will age, resulting in leakage.Illegal operation of the staff. Cause ammonia leakage. If the worker operates improperly, the liquid ammonia or equipment oil enters the compressor cylinder, causing excessive pressure in the cylinder and causing a leakage accident at the top of the cylinder head. When the workers stacked the goods, they couldn't stack them. After the goods were frozen and hardened, they suddenly collapsed, causing the evaporation tube to crack and the gas to leak. During loading and unloading, the loader was working in the cold storage room and accidentally broke the evaporation tube on the wall, causing leakage. The compressor is running normally. If the worker accidentally closes the valve from the compressor to the condenser, this section of the pipeline may burst.

2. Solution

Monitoring location: cold storage liquid ammonia storage tank area, refrigeration equipment assembly workshop, loading and unloading site, ammonia transmission pipeline

Monitoring gas: ammonia

Data transmission: According to the actual situation of the cold storage site, install an ammonia detection alarm at each monitoring position. If there is an ammonia leakage, the detected ammonia concentration data will be transmitted to the controller in the form of current signal or wireless transmission as soon as possible, and the gas cut-off valve will be linked to quickly cut off the gas transmission. Transmission root cause, start the on-site exhaust system, quickly eliminate toxic gases, and ensure the safe operation of on-site personnel and the normal operation of equipment

3. What products are matched:

Product name: online ammonia gas detection alarm

Model: MIC-600-NH2-A-X

Detection range 0-500ppm Resolution 0.1ppm

Imported electrochemical principle sensor

controller, model MIC200

The picture is as follows: