Introduction to the structure and types of traps
Traps are also called drain valves orsteam trapmainly used to remove the air and carbon dioxide in the steam system andcondensateThe gas is discharged as soon as possible, and the leakage of steam can be prevented to the greatest extent. So what are the structures and types of traps? The following will give you a detailed introduction.
1. Free float trap:
The structure of the free float trap is simple. There is only a finely ground stainless steel hollow float inside, which is both a float and an opening and closing part. There are no vulnerable parts and a long service life. “Silver Ball” free float trap There is an automatic air exhaust device inside the valve, which is very sensitive and works with high quality. The valve seat of the free floating ball trap is always below the liquid level, forming a water seal, no steam leakage, and good energy saving effect. Free float traps are not affected by fluctuations in temperature and working pressure, and discharge continuously. It can drain the condensed water at saturation temperature, and there is no water in the heating equipment, so that the heating equipment can achieve better heat exchange efficiency, and the back pressure rate is greater than 85%. It is one of the ideal steam traps for heating equipment in the production process.
2. Free semi-floating ball trap:
The free semi-floating ball trap has only one semi-floating ball bucket as the moving part, with the opening facing down. Durable and no steam leakage. The back pressure rate is greater than 85%, which can drain the condensed water at the saturation temperature, and the minimum subcooling degree is 0 °C, and there is no water in the heating equipment, so that the heating equipment can achieve better heat exchange efficiency.
3. Lever float trap:
The basic features of the lever float type steam trap are the same as those of the free float type. The lever float trap uses double valve seats to increase the condensate discharge, which can achieve a small volume and obtain a large discharge. The maximum drain capacity of the lever float type trap can reach 65 tons/hour, and it is an ideal trap for large heating equipment.
4. Inverted bucket type steam trap (bell float type):
The inside of the inverted bucket trap is an inverted bucket as a liquid level sensitive component. The opening of the bucket is downward, and the connection lever of the inverted bucket drives the valve core to open and close the valve. The inverted bucket type trap can discharge air, is not afraid of water hammer, has a small subcooling degree, a maximum back pressure rate of 85%, and is intermittently drained.
This type of trap uses the temperature difference between steam and condensed water to cause the deformation or expansion of the temperature sensing element to drive the valve core to open and close the valve. The degree of subcooling of the thermostatic trap is relatively large, generally 15 degrees to 40 degrees. It can utilize part of the sensible heat in the condensed water. There is always high temperature condensed water in front of the valve, no steam leakage, and the energy saving effect is remarkable. .
Thermostatic steam traps include bellows type, bellows type, and bimetallic sheet type—–
1. Diaphragm trap:
The main action element of the bellows type steam trap is the metal bellows. The bellows is filled with a liquid whose vaporization temperature is lower than the saturation temperature of water. There are two options: 15°C and 30°C when the valve opening temperature is lower than the saturation temperature. Capsule-type steam traps are particularly sensitive in response, not afraid of freezing, small in size, resistant to overheating, can be installed in any position, with a back pressure rate greater than 70%, can discharge non-condensing gas, sturdy bellows, long service life, easy maintenance, and use The range is wide.
2. Bellows type trap:
The stainless steel bellows of the valve core of the bellows trap is filled with a liquid whose vaporization temperature is lower than the water saturation temperature. The valve switch is controlled with the change of steam temperature. The valve is equipped with adjustment bolts to adjust the operating temperature according to the needs. Generally, the adjustment range of the subcooling degree is lower than the saturation temperature of 15℃-40℃, and the back pressure rate is greater than 70%. It is not afraid of freezing and is small in size. Installed in any position, it can discharge non-condensable gas and has a long service life.
3. Bimetallic disc trap:
The main component of the bimetallic sheet steam trap is the bimetallic sheet temperature sensing element, which is heated and deformed with the rise and fall of the steam temperature, and pushes the valve core to open and close the valve. The bimetallic sheet steam trap is equipped with adjustment bolts, which can adjust the operating temperature according to the needs. Generally, the adjustment range of the subcooling degree is lower than the saturation temperature of 15℃-10℃, and the back pressure rate is greater than 70%. It can discharge non-condensing gas and is not afraid of freezing. Small size, water hammer resistance, high pressure resistance, and can be installed in any position. Bimetals are fatigued and require frequent adjustment.
According to the principle of phase change, this type of trap relies on the different thermodynamic principles of flow rate and volume change when steam and condensate pass through, so that different pressure differences are generated up and down the valve plate to drive the valve plate to open and close the valve. Because the working power of the thermodynamic trap comes from steam, the steam waste is relatively large. Simple structure, water hammer resistance, 50% larger back, noise, frequent valve work, short service life.
Thermodynamic steam traps include thermodynamic (disc type), pulse type, orifice type—–
1. Thermodynamic steam trap
There is a movable valve plate in the thermodynamic steam trap, which is both a sensitive part and an action execution part. According to the different thermodynamic principles of the flow rate and volume change of steam and condensate passing through, different pressure differences are generated up and down the valve plate to drive the valve plate to open and close the valve. The national standard stipulates that the air leakage rate of qualified products is 3%-5%, the subcooling degree is 8℃-15℃, intermittent drainage, the maximum back pressure rate is 50%, there is noise, the valve piece works frequently, and the service life is short.
2. Disc type steam insulation trap:
The working principle of the disc steam insulation trap is the same as that of the thermodynamic steam trap. It adds a layer of shell outside the steam chamber of the thermodynamic steam trap. The inner chamber of the shell is communicated with the steam pipe, and the main steam chamber of the trap is kept warm by the steam of the pipe itself. The temperature of the main steam chamber is not easy to cool down, the steam pressure is maintained, and the steam trap is tightly closed. When the pipeline produces condensed water, the trap casing cools down, and the trap starts to drain; if there is no condensed water on the superheated steam pipeline, the trap will not open, and the working quality is high. The valve body is made of alloy steel, and the valve core is made of hard alloy. The maximum allowable temperature of the valve is 550 ℃, which is durable and has a long service life. It is a special trap for high pressure, high temperature and superheated steam.
3. Pulse trap:
The pulse trap has two orifice plates, which adjust the valve switch according to the change of steam pressure drop. Even if the valve is completely closed, the inlet and outlet are connected through the first and second small holes, and they are always in a state of incomplete closure, and the steam continuously overflows and leaks. Air volume. The trap has a high frequency of action, severe wear and short life.
4. Orifice trap:
The orifice trap is to select orifices with different apertures according to different drainage to achieve the purpose of controlling paishuiliang. The structure is simple, and if the selection is not appropriate, there will be insufficient drainage or a large amount of soda water. It is not suitable for steam-using equipment for intermittent production or steam-using equipment with large fluctuations in condensed water volume.
The structure and types of traps in the above four categories are introduced in great detail. They will definitely be of great help to you. Hurry up and collect them~