Welded Threaded Pipe Fittings

To determine whether the pressure of Welded Threaded Pipe Fittings is abnormal,comprehensive consideration can be made from multiple dimensions.The following is a detailed introduction to the specific judgment method:

Application of pressure monitoring equipment

Observation of pressure gauge

Stable operation comparison:When the pipeline system where the threaded fittings are located is running stably,pay close attention to the value on the pressure gauge.Firstly,clarify the pressure range of the pipe fitting under normal operating conditions,which can refer to the design parameters of the pipe fitting,the operating manual of the equipment,or past operating records.If the pressure value displayed on the current pressure gauge continues to deviate from the normal range,it may indicate that there is an abnormality in the pressure.For example,if the normal operating pressure should be between 1-2MPa,but the actual pressure gauge shows 2.5MPa,further investigation of the cause is needed.

Analysis of Fluctuations:In addition to focusing on the absolute value of stress,it is also important to pay attention to the fluctuations of stress.Under normal circumstances,there will be some small fluctuations in pressure,but if the fluctuation amplitude exceeds the normal allowable range or the fluctuation frequency is abnormal,such as frequent large fluctuations,it also indicates that there is an abnormality in pressure.For example,if the original pressure fluctuation was within±0.1MPa,but suddenly there is a significant fluctuation of±0.5MPa,it may indicate problems such as blockage,leakage,or equipment failure in the pipeline system.

Pressure sensor data collection

Real time data monitoring:With the help of pressure sensors,real-time and accurate monitoring of pressure on threaded pipe fittings can be achieved.Install the pressure sensor in the appropriate position and transmit the pressure data to the monitoring terminal through the data acquisition system.Analyze the data collected by sensors and observe the trend of pressure changes over time.If there are abnormal peaks,valleys,or sudden changes in the pressure curve,it indicates that the pressure may be abnormal.

Comparison with historical data:Establish a historical database of pressure data and compare the currently collected data with historical data.If there is a significant difference between the current pressure data and historical data under the same operating conditions,it may indicate abnormal pressure.For example,under the same flow and temperature conditions,historical pressure data remains stable at around 1.2 MPa,while the current pressure sensor displays 1.5 MPa,which requires a thorough analysis of the cause.

Assessment of system operation status

The correlation between flow and pressure

Theoretical relationship judgment:There is a certain theoretical relationship between flow rate and pressure in pipeline systems.According to the principles of fluid mechanics,under constant conditions such as pipe diameter and medium,an increase in flow rate usually leads to an increase in pressure,while a decrease in flow rate results in a decrease in pressure.If it is found that the changes in flow and pressure do not conform to this normal correlation,it may indicate abnormal pressure.For example,if there is no significant change in flow rate but the pressure increases significantly,this may be caused by pipeline blockage or valve failure.

Equipment performance impact:The performance of pumps,compressors,and other equipment in the system can also affect the relationship between flow rate and pressure.If these devices malfunction or operate abnormally,it may lead to unstable pressure.For example,wear and tear on the impeller of a pump can reduce its head,leading to a decrease in pressure;And a malfunction in the intake valve of the compressor may cause an abnormal increase in pressure.Therefore,it is necessary to comprehensively consider the operating status of the equipment to determine whether the pressure is normal.

The Effect of Temperature on Pressure

Principle of thermal expansion and contraction:Changes in temperature can cause thermal expansion and contraction of the medium,thereby affecting the pressure of the pipeline system.According to the ideal gas state equation or the thermal expansion coefficient of a liquid,in a closed pipeline system,an increase in temperature will cause an increase in pressure,and a decrease in temperature will cause a decrease in pressure.Therefore,when determining whether the pressure is abnormal,the influence of temperature needs to be considered.For example,in high temperature environments during summer,the temperature of the medium inside the pipeline may increase,and the pressure may correspondingly increase.However,if the increase exceeds the reasonable range calculated based on temperature changes,there may be other problems.

Temperature change rate:In addition to the absolute value of temperature,the rate of temperature change also affects pressure.If the temperature suddenly increases or decreases significantly,it may cause a sharp change in pressure that exceeds the capacity of the pipe fittings.Therefore,it is necessary to pay attention to the rate of temperature change and combine it with the change in pressure to determine whether there is an abnormality.

Abnormal signs of pipe fittings and systems

Appearance inspection of pipe fittings

Leakage and deformation:Check the appearance of threaded fittings to see if there are any leaks,deformations,etc.If there is a leak in the pipe fittings,the pressure may decrease;The deformation of pipe fittings,such as expansion,distortion,etc.,may be caused by excessive pressure.For example,if there are signs of liquid or gas leakage at the connection of the pipe fittings,and the pressure gauge shows a gradual decrease in pressure,it indicates that the pressure is abnormal.

Loose connection part:Check if the threaded connection part of the pipe fitting is loose.Loose connections may lead to pressure loss,causing unstable system pressure.It can be determined whether the connection is firm by observing whether there are gaps in the connection parts and whether the sealing material is extruded.

System sound and vibration

Abnormal sound judgment:Listen to whether there are any abnormal sounds during the operation of the pipeline system,such as sharp whistling sounds,impact sounds,etc.These abnormal sounds may be caused by abnormal pressure,for example,excessive pressure inside the pipeline may cause high-speed flow of the medium,resulting in whistling sounds;Excessive pressure fluctuations may cause collisions between pipe fittings,resulting in collision sounds.

Vibration situation analysis:feel the vibration situation of the pipeline system.Under normal circumstances,pipelines may experience slight vibrations,but if the vibration intensifies significantly or exhibits abnormal vibration frequencies,it may be related to abnormal pressure.For example,unstable pressure may cause uneven flow of the medium inside the pipeline,leading to increased vibration of the pipeline.