Explanation of absolute pressure, gauge pressure, vacuum degree and vacuum pressure
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Explanation of absolute pressure, gauge pressure, vacuum degree and vacuum pressure
Explanation of absolute pressure, gauge pressure, vacuum degree and vacuum pressure
Q: What is pneumatic technology? What is the English word for pneumatic?
A: Pneumatic technology is an engineering technology that uses air compressors as power sources and compressed air as working medium to transfer energy or signals. It is one of the important means to achieve various production control and automatic control. Pneumatic is the abbreviation of “pneumatic technology” or “pneumatic transmission and control”. The English word for pneumatic is: PNEUMATIC.
Q : What are the characteristics of pneumatic technology?
A :Pneumatic technology has the advantages of simple structure, low pressure level, safe use, convenient maintenance, simple installation, etc., which can achieve fire prevention, explosion prevention and moisture resistance.
The disadvantages of pneumatic technology are that the positioning accuracy is not high, the speed characteristics are greatly affected by the load, and the output force is lower than that of hydraulic pressure.
Q : What is absolute pressure? What is gauge pressure? What is vacuum degree? What is vacuum pressure? What is the relationship between them?
A : Absolute pressure is the pressure value starting from absolute vacuum . Generally, “ABS” should be marked in the lower right corner of the symbol representing absolute pressure, that is, Pabs.
Gauge pressure refers to the pressure value higher than the local atmospheric pressure. It is generally not marked. If necessary, “e”, i.e. Pe, can be marked in the lower right corner.
Vacuum degree refers to the pressure value (positive value) lower than the local atmospheric pressure .
Vacuum pressure refers to the difference between absolute pressure and atmospheric pressure (negative value) . The vacuum pressure is the same as the vacuum degree in value, but a negative sign should be added before its value.
The relationship between absolute pressure, gauge pressure and vacuum pressure is: absolute pressure = gauge pressure (vacuum pressure) + local atmospheric pressure.
Q: What are standard status and benchmark status?
A: Standard state refers to the state of air at a temperature of 20°C, a relative humidity of 65%, and a pressure of 0.1 MPa. Under standard state, the density of air is 1.185 kg/m 3 . According to ISO8778, the unit under standard state can be followed by “(ANR)”, such as 30m 3 /h(ANR).
The reference state refers to the state of dry air with a temperature of 0°C and a pressure of 101.3 kPa. In the reference state, the air density is 1.293 kg/m 3 .
Q: What is a perfect gas? What is the equation of state of a perfect gas?
A: Perfect gas is a hypothetical gas whose molecules are elastic particles that do not occupy volume. There is no interaction between molecules except for mutual collision. It is completely different from the concept of ideal gas. The state equation of perfect gas: pv = RT or p = ρRT = (m/V)RT.
Q: What is absolute humidity? What is relative humidity?
A: The mass of water vapor contained in each cubic meter of wet air is called absolute humidity , that is, the water vapor density of wet air. The content of water vapor in wet air has a limit. At a certain temperature and pressure, when the water vapor in the air reaches the maximum possible content, the air at this time is called saturated air. The state of saturated air is called saturated state. Below 2MPa pressure, it can be approximately considered that the density of water vapor in saturated air has nothing to do with pressure and only depends on temperature. The ratio of the actual water vapor content in each cubic meter of wet air (that is, the water vapor density of unsaturated air) to the maximum possible water vapor content at the same temperature (that is, the saturated water vapor density) is called relative humidity.
Q: What is dew point? What is pressure dew point?
A: The temperature of unsaturated air when the water vapor partial pressure remains unchanged and the temperature is lowered to reach the saturated state is called the dew point. When the temperature drops below the dew point, water droplets will precipitate from the wet air. The temperature at which water droplets begin to precipitate after the wet air is compressed is called the pressure dew point. The higher the pressure, the higher the temperature at which water droplets begin to precipitate.
A: Pneumatic technology is an engineering technology that uses air compressors as power sources and compressed air as working medium to transfer energy or signals. It is one of the important means to achieve various production control and automatic control. Pneumatic is the abbreviation of “pneumatic technology” or “pneumatic transmission and control”. The English word for pneumatic is: PNEUMATIC.
Q : What are the characteristics of pneumatic technology?
A :Pneumatic technology has the advantages of simple structure, low pressure level, safe use, convenient maintenance, simple installation, etc., which can achieve fire prevention, explosion prevention and moisture resistance.
The disadvantages of pneumatic technology are that the positioning accuracy is not high, the speed characteristics are greatly affected by the load, and the output force is lower than that of hydraulic pressure.
Q : What is absolute pressure? What is gauge pressure? What is vacuum degree? What is vacuum pressure? What is the relationship between them?
A : Absolute pressure is the pressure value starting from absolute vacuum . Generally, “ABS” should be marked in the lower right corner of the symbol representing absolute pressure, that is, Pabs.
Gauge pressure refers to the pressure value higher than the local atmospheric pressure. It is generally not marked. If necessary, “e”, i.e. Pe, can be marked in the lower right corner.
Vacuum degree refers to the pressure value (positive value) lower than the local atmospheric pressure .
Vacuum pressure refers to the difference between absolute pressure and atmospheric pressure (negative value) . The vacuum pressure is the same as the vacuum degree in value, but a negative sign should be added before its value.
The relationship between absolute pressure, gauge pressure and vacuum pressure is: absolute pressure = gauge pressure (vacuum pressure) + local atmospheric pressure.
Q: What are standard status and benchmark status?
A: Standard state refers to the state of air at a temperature of 20°C, a relative humidity of 65%, and a pressure of 0.1 MPa. Under standard state, the density of air is 1.185 kg/m 3 . According to ISO8778, the unit under standard state can be followed by “(ANR)”, such as 30m 3 /h(ANR).
The reference state refers to the state of dry air with a temperature of 0°C and a pressure of 101.3 kPa. In the reference state, the air density is 1.293 kg/m 3 .
Q: What is a perfect gas? What is the equation of state of a perfect gas?
A: Perfect gas is a hypothetical gas whose molecules are elastic particles that do not occupy volume. There is no interaction between molecules except for mutual collision. It is completely different from the concept of ideal gas. The state equation of perfect gas: pv = RT or p = ρRT = (m/V)RT.
Q: What is absolute humidity? What is relative humidity?
A: The mass of water vapor contained in each cubic meter of wet air is called absolute humidity , that is, the water vapor density of wet air. The content of water vapor in wet air has a limit. At a certain temperature and pressure, when the water vapor in the air reaches the maximum possible content, the air at this time is called saturated air. The state of saturated air is called saturated state. Below 2MPa pressure, it can be approximately considered that the density of water vapor in saturated air has nothing to do with pressure and only depends on temperature. The ratio of the actual water vapor content in each cubic meter of wet air (that is, the water vapor density of unsaturated air) to the maximum possible water vapor content at the same temperature (that is, the saturated water vapor density) is called relative humidity.
Q: What is dew point? What is pressure dew point?
A: The temperature of unsaturated air when the water vapor partial pressure remains unchanged and the temperature is lowered to reach the saturated state is called the dew point. When the temperature drops below the dew point, water droplets will precipitate from the wet air. The temperature at which water droplets begin to precipitate after the wet air is compressed is called the pressure dew point. The higher the pressure, the higher the temperature at which water droplets begin to precipitate.
