Pressure gauges are the most common measuring instruments in industrial production and are widely used in various fields of industrial production. It can more intuitively display the pressure changes of each process link, monitor the safety status in the industrial production process, especially the pressure gauges installed on the pressure vessels and pressure pipelines, pressure fluctuations play a key role in preventing catastrophic accidents. . However, in actual production and life, pressure gauges are generally ignored or illegally used, which brings hidden dangers to safety.
(1) Installation does not meet specifications
① Some pressure gauges installed on pressure vessels and pressure pipelines are too small to be easily observed by operators.
② There is no three-way cock or needle valve installed between the pressure gauge and the pressure vessel or pressure pipeline, and the pressure gauge is directly installed on the valve, which will damage the interface of the pressure gauge for a long time.
③ For the pressure gauge used to observe the water vapor medium, no trap is installed between the pressure gauge and the pressure vessel or pressure pipeline.
④ Under high pressure conditions such as the installation of pressure vessels and pressure pipelines, freely change the regulations in the specification for installation.
(2) The selection does not meet the specification requirements
The selected pressure gauge must be compatible with the medium in the pressure vessel or pressure pipeline.
The accuracy of pressure gauges used in low-pressure containers should not be lower than 2.5; the accuracy of pressure gauges used in medium-pressure and high-pressure containers should not be lower than 1.5.
A pressure gauge with a larger range is selected for the quantity with a smaller measurement value, and a pressure gauge with a smaller range is selected for the quantity with a larger measurement value, resulting in inaccurate or damaged pressure measurement value.
(3) Insufficient attention to daily use and maintenance
In daily use, the pressure gauge is not checked and cleaned regularly, causing impurities in the medium to block the spring tube of the pressure gauge; no usage records are recorded in daily use; when the needle does not return to zero or fluctuates severely, the explosion-proof hole protective film falls off, and the dial Corrosion or glass breakage is still in use, etc.
(4) The weekly inspection work is not implemented properly
The calibration period of the pressure gauge is generally half a year. According to the "Measurement Law", the pressure gauge is a measuring instrument for compulsory verification, and the compulsory verification is a legal measure to ensure the reliable technical performance of the pressure gauge, the accurate transmission of the value, and the effective guarantee of safe production. However, in the verification process of some verifiers, in order to save time, the voltage stabilization at the maximum range is less than 3 minutes; some users do not understand the safety function of the pressure gauge in place, do not apply for verification in advance, and the phenomenon of over-period verification is very serious. , In particular, the newly purchased pressure gauge can only be installed and used after passing the verification, but the first verification rate of the new meter is still very low.
(1) Standard installation
① Install in strict accordance with the requirements of the specification, and the installation location should be easy for operators to observe and clean.
② A three-way cock or a needle valve should be installed between the pressure gauge, the pressure vessel and the pressure pipeline; the opening mark and locking device should be provided on the three-way cock or the needle valve; no other connections should be made between the pressure gauge and the pressure vessel. Use any fittings or takeovers.
③ For the pressure gauge used for water vapor medium, a water trap shall be installed between the pressure gauge and the pressure vessel.
④ For pressure gauges with corrosive or high viscosity medium, a buffer device for isolating medium should be installed between the pressure gauge and the pressure vessel.
⑤ The limit value of the pressure dial scale should be 1.5~3.0 times the maximum working pressure, preferably 2 times.
(2) Select the corresponding pressure gauge according to the medium used on site, the required grade and the measuring range.
(3) The pressure gauge should be checked and cleaned regularly, and the operation record should be kept. If the cover glass of the dial is broken or the scale of the dial is blurred, the seal is damaged or exceeds the validity period of the calibration, the spring tube in the watch leaks or the pointer of the pressure gauge is loose or the dial glass is broken, it should be replaced immediately to ensure accurate counting and reduce the risk of safety accidents. occur.
(4) Strictly carry out the verification in accordance with the verification regulations of the pressure gauge, and it is strictly forbidden to use it over a period of time. Especially, the newly purchased pressure gauge must be verified before it can be installed and used.
In conclusion, the correct use of pressure gauges is the responsibility of every safety producer. First of all, enterprises that use pressure gauges should continuously strengthen the training of safety knowledge, improve their awareness of safety responsibility, and fully understand the role of pressure gauges in industrial production; It is required to deal with unqualified or downgraded pressure gauges to ensure accurate and reliable values; finally, the measurement supervision department must strictly regulate and standardize requirements, focus on monitoring the irregularities in the use of pressure gauges, and investigate and deal with irregular operations in accordance with the usage specification.