Maintenance of pressure gauges
In order to keep the pressure gauge sensitive and accurate, in addition to the reasonable selection and correct installation, the maintenance and inspection of the pressure gauge should be strengthened during the operation of the boiler and pressure vessel.
1. To maintain the pressure gauge, the following work should be done:
1. The pressure gauge should be kept clean, and the glass on the dial should be bright and clear, so that the pressure value indicated by the pointer on the dial is easy to identify. And pressure gauges with broken glass on the dial or blurred dial scales should be abolished.
2. The connecting pipe of the pressure gauge should be blown regularly to avoid blockage, especially the connecting pipe used for oily dirt or other gas with more viscous substances.
3. Always check whether the rotation and fluctuation of the pointer of the pressure gauge are normal, and whether the cock on the connecting pipe is in the fully open position.
4. The pressure gauge must be calibrated regularly, and the frequency can be determined according to the specific situation:
1) After the pressure gauge has been in operation for three months, first-level maintenance must be carried out, mainly to check whether the pressure gauge can be returned to zero, and whether the tee and trap joints are leaking. And we have to check and flush the trap to make sure it's clear.
2) After one year of operation, secondary maintenance must be performed. At this time, the pressure gauge can be disassembled and sent to the measurement department for verification and lead sealing. When we disassemble and inspect the trap, the threaded fasteners should be found intact. Disassemble and check the three-way cock, grind the sealing surface to ensure that the sealing is not leaking, and the connecting thread should be intact. Store traps, remove rust and paint tee cocks.
5. The pressure gauge is not on time during operation and must be replaced in time. The replaced pressure gauge must be a lead-sealed pressure gauge verified by the metrology department within the validity period of the verification or a new one with a factory certificate. Before replacing the instrument, the three-way cock must be screwed to the position of flushing the pressure gauge, and the dirt in the drain pipe must be flushed.
The above is about the maintenance method of the pressure gauge. After the pressure gauge calibrator is used in the first grade, the internal oil circuit should be cleaned regularly, and the fresh medium should be replaced to prevent the inspected personnel from blocking the pipeline and corroding the body. The service life of the pressure gauge and the accuracy of the results can only be extended by the correct use and attention to maintaining the instrument.
II. Use of pressure gauges
Pressure gauges are mechanical devices commonly used in industrial control and measurement processes. Pressure gauges can be divided into mechanical pressure gauges and electronic pressure gauges. Mechanical pressure gauges are widely used because of their good elastic elements and high mechanical strength, especially in industrial production.
The working principle of the mechanical pressure gauge is to indicate the pressure value through the elastic deformation of the internal elastic sensitive element under the action of pressure. Mechanical pressure gauges generally use spring tubes, diaphragms, and bellows as elastic elements. After these elastic elements are deformed, they will be enlarged by the gear transmission mechanism to display the corresponding pressure value.
The pressure measured by the meter is relative because atmospheric pressure is a relative point. The result displayed by the pressure gauge is also the pressure of the measured object under the atmosphere. The pointer indicates the pressure value within the measuring range of the pressure gauge, and the dial corresponding to the pointer is usually 270 degrees.
1. The role of the pressure gauge:
Pressure is one of the most important process parameters in industrial production. If the pressure does not meet the requirements, it will affect production efficiency, reduce product quality, and even cause serious accidents. Therefore, pressure measurement has a special place in industrial production. Correct use of pressure gauges is necessary for accurate pressure measurement.
The danger of the pressure gauge itself is low, especially compared to the production system it monitors, it is almost negligible. The reason why it is necessary to attach great importance to the use of pressure gauges is that pressure gauges are the premise of automatic interlocking devices, sensing devices and protection devices, and are the way for various reaction devices to obtain pressure information.
The role of pressure gauges in production systems is irreplaceable. Small problems in the operation of pressure gauges may have hidden dangers, especially pressure gauges used to monitor dangerous substances such as flammable, explosive, corrosive, and toxic substances. Once the pressure measurement is wrong, it may directly lead to the leakage of harmful substances, resulting in a huge environmental disaster. Safe use of pressure gauges is the responsibility of every company and every operator. This requires companies that use pressure gauges to fundamentally improve the safety of pressure gauges, systematically reduce pressure gauge safety risks, and provide a good environment for use.
Second, the three major hidden dangers of pressure gauges and their elimination methods
Pressure gauges are common measuring instruments. With the development of the instrument industry, pressure gauges have been widely used in various fields such as industrial production.
This pressure gauge can intuitively display the pressure changes in each process link, gain insight into the state formation of the product or medium process, monitor the safety trend in the production operation process, and build fast and reliable safety guarantees through automatic interlocks or sensing devices. This plays an important role in preventing accidents, protecting people and property, and is called the "eyes" of safety.
However, in actual production and life, the pressure gauge is ignored or used illegally, which brings hidden dangers to safety. Usually as shown below:
1). Irregular installation and configuration.
Current regulations have clear requirements for the configuration, installation, use, maintenance and inspection of pressure gauges. The problem is prominent because in actual assembly, there are many arbitrary variations of the specifications. In small parts or double (multiple) meter monitoring places, reduce the number of settings, the disk diameter and range are not suitable for the work requirements, and use special meters under special conditions such as flammable, explosive, toxic, and corrosive.
2). Insufficient attention to daily use and maintenance. Inspection and cleaning of equipment during use are irregular. There is no record of use, the pointer does not return to zero or fluctuates violently, the protective film of the explosion-proof hole is peeled off, the dial is corroded or the glass is broken, and the dial is unclean.
3). Acceptance work has not been implemented. The calibration cycle of the pressure gauge is usually once every six months. Mandatory verification is a legal measure to ensure reliable technical performance of pressure gauges, accurate value transmission, and safe and effective production. Because some users do not have a good understanding of the safety function of the pressure gauge, they did not apply for verification in advance. So exceeding the verification period is very serious. Especially the newly purchased pressure gauge can be installed and used after passing the verification, but the verification rate of the new instrument for the first use is still very low.
Compared to production systems, the pressure gauges are too small to cause any accidents. However, with the pressure gauge as the main device, the automatic interlocking device, the sensing device and the protection device as the supporting parts, the tiny and subtle visual perception, the fortress of safe construction is irreplaceable. "A thousand-mile-long dyke collapses in an ant's nest." Despising and ignoring details is a desecration of safety. As one of the safety accessories, the pressure gauge not only displays several pressure figures, but also monitors the smallest "leakage holes" with its smart "eyes", always guarding the door for product safety, personal safety and environmental safety. Especially when used in dangerous places such as production, storage, and transportation of flammable and explosive materials, explosive and toxic substances, and pressure factors play a key role in preventing catastrophic accidents. The contribution of pressure gauges to safety cannot be underestimated. First of all, users should continuously improve their safety awareness and sense of responsibility, and truly manage and make good use of the characteristics of the pressure gauge, so that it can play the role of "eyes"; second, the testing and verification agency should actively verify the pressure gauge and downgrade it in time. Pressure gauges that do not meet the requirements for use shall be scrapped to ensure accurate measurement values and reliable performance; at the same time, the regulatory authorities shall strictly supervise the use of pressure gauges, and investigate and punish illegal operations and illegal use in accordance with the law. Let us start from the details and foundation, light up the "eyes" of safety, and build a strong and safe long embankment together.
