The water valve acts as a steam-blocking effect in the steam heating system, and the selection of a suitable steam trap can achieve the highest working efficiency of the steam heating equipment. In order to achieve the best results, a comprehensive understanding of the performance and characteristics of various types of traps is required.

There are many types of traps, each with different properties. When using a steam trap, first select the special performance to meet the optimal operation of the steam heating equipment, and then consider other objective conditions, so that the choice of the trap you need is correct and effective.

Traps should be able to "recognize" steam and condensate in order to function as a vapor barrier. “Identification” Steam and condensate are based on three principles: density difference, temperature difference, and phase change. Three types of traps were then produced according to three principles: classified as mechanical, thermostatic, and thermodynamic.

1. Mechanical type steam trap: The mechanical type is also called the float type. It uses the difference of the density of condensed water and steam. Through the change of the condensed water level, the float lifts the valve flap to open or close, and achieves the purpose of blocking steam. The mechanical type steam trap has a small degree of subcooling and is not affected by the working pressure and temperature change. Water is discharged, and no water is stored in the heating device, so that the heating device can achieve the best heat exchange efficiency. With a maximum back pressure of 80% and high working quality, it is the most ideal steam trap for production process heating equipment.

Mechanical traps are free float type, free half float type, lever float type, inverted bucket type, etc.

1. Free float trap: The free float trap has a simple structure. There is only one stainless steel hollow float with fine moving parts inside. It is both a float and a starter, no fragile parts, and has a long service life. The “YQ” trap has a Y-series automatic air exhaust unit inside, which is very sensitive and can automatically discharge air and has high work quality. When the equipment is started, the air in the pipeline is discharged through the Y series automatic air exhaust device. The low temperature condensed water enters the trap. The liquid level of the condensate rises, the float rises, the valve opens, the condensate is quickly discharged, and the steam enters quickly. The equipment and equipment are rapidly warmed up, and the temperature-sensitive liquid of the Y-series automatic air-discharging device expands, and the automatic air-discharging device is closed. The trap begins to work normally, and the float moves up and down with the condensate level, blocking steam drainage. The valve seat of the free float trap is always below the liquid level, forming a water seal, no steam leakage, and the energy saving effect is good. The minimum working pressure is 0.01Mpa, and it is not affected by temperature and working pressure fluctuations from 0.01Mpa to the maximum operating pressure range, and continuous drainage. It can discharge condensed water with saturated temperature, the minimum degree of subcooling is 0 °C, and there is no water in the heating equipment, which can make the heating equipment achieve the best heat exchange efficiency. With a back pressure of more than 85%, it is one of the most ideal steam traps for production process heating equipment.

2. Free semi-float trap: Free half-float trap has only one semi-float ball bucket as the moving part, with the opening facing down, the bucket is the opening and closing part and the seal. The entire spherical surface can be sealed, has a long service life, can resist water hammer, has no wearing parts, no faults, is durable, and has no steam leakage. The back pressure ratio is more than 80%, and the condensed water can be discharged at a saturated temperature. The minimum degree of subcooling is 0 ° C. There is no water in the heating equipment, which can make the heating equipment achieve the best heat exchange efficiency. When the device is just started, the air and low-temperature condensate in the pipeline enter the trap through the launch tube. The bimetal evacuation element in the valve bounces the bucket, the valve opens, and the air and low-temperature condensate are quickly discharged. When the steam enters the barrel, the barrel produces upward buoyancy, while the temperature inside the valve rises, the bimetal evacuation element contracts, the ball floats toward the valve port, the shutoff valve, the solenoid valve, and the valve close. When the steam in the bucket becomes condensed water, the bucket loses buoyancy and sinks, the valve opens, and the condensate is quickly discharged. When the steam re-enters the barrel, the valve closes again, intermittently and continuously.

3. Rod float type trap: The basic characteristics of the lever float type trap are the same as that of the free float type. The regulating valve and the pressure reducing valve are internal. The internal structure is the float connecting rod to drive the valve core, and the liquid level rises and falls with the condensate. Switch the valve. The lever float trap uses a double seat to increase the condensate displacement, which can achieve a small volume and a maximum displacement of 100 tons per hour. It is the most ideal steam trap for large heating equipment.

4. Inverted bucket type steam trap: The inside of the inverted bucket type trap is an inverted bucket for the liquid level sensitive part, the bucket opening is downward, and the inverted bucket connecting the lever drives the valve core opening and closing valve. The inverted bucket type trap can discharge air, is not afraid of water hammer, and has good anti-fouling performance. The degree of undercooling is small, the leakage rate is less than 3%, the maximum back pressure is 75%, the connection is more, and the sensitivity is not as good as that of the free float trap. Because the inverted bucket type steam trap is closed by steam buoyancy, the working pressure difference is less than 0.1MPA, which is not suitable for use. When the device is just started, the air in the pipeline and the low-temperature condensed water enter the trap, and the inverted bucket falls by its own weight. The inverted bucket connects the lever to drive the valve to open the valve, and the air and low-temperature condensate are quickly discharged. When the steam enters the inverted bucket, the steam of the inverted bucket generates upward buoyancy, and the inverted bucket rises to connect the lever to drive the valve core to close the ball valve and the gate valve. There is a small hole in the inverted bucket. When a part of the steam is discharged from the small hole, the other part of the steam generates condensed water. The inverted bucket loses buoyancy and sinks by its own weight. The inverted bucket connects the lever to drive the valve to open the valve. Work, intermittent drainage.

5. Combined superheated steam trap: The combined superheated steam trap has two isolated valve chambers, which are connected by two stainless steel tubes to the upper and lower valve chambers. It is a combination of a float type and an inverted bucket type trap. The structure is advanced and reasonable. Under the working conditions of overheating, high pressure and small load, the condensed water formed when the superheated steam disappears can be discharged in time, effectively preventing the superheated steam from leaking, and the work quality is high. The maximum allowable temperature is 600 °C, the valve body is all stainless steel, the valve seat is made of hard alloy steel, and the service life is long. It is a special steam trap for superheated steam. It has obtained two national patents and filled the domestic blank. When the condensed water enters the lower valve chamber, the float of the sub-valve rises with the liquid level, and the float ball closes the inlet of the steam pipe. The condensed water rises to the main valve chamber through the water inlet conduit, and the inverted bucket falls by its own weight, driving the valve core to open the main valve and discharging the condensed water. When the condensate level of the secondary valve chamber drops, the float drops with the liquid level and the secondary valve opens. The steam enters the inverted bucket in the upper main valve chamber from the inlet pipe, and the inverted bucket generates upward buoyancy, and the inverted bucket drives the valve core to close the main valve. When the condensate level of the secondary valve chamber rises again, the next cycle begins again, intermittently draining.

2. Thermostatic Traps: These traps use the temperature difference between steam and condensate to cause the deformation or expansion of the temperature sensing element to drive the valve opening and closing valve. The thermostatic trap has a relatively large degree of subcooling. Generally, the degree of subcooling is 15 to 40 degrees. It can utilize a part of sensible heat in the condensed water. There is always high temperature condensate before the valve, no steam leakage, and the energy saving effect is remarkable. . It is the ideal steam trap in steam pipes, heat tracing pipes, small heating equipment, heating equipment, and small heating equipment with low temperature requirements.

Thermostatic traps are bellows, bellows, bimetal

1. Membrane type trap: The main action component of the bellows type trap is a metal bellows filled with a liquid whose vaporization temperature is lower than the saturation temperature of water, and the valve opening temperature is lower than the saturation temperature by 15 °C. 30 ° C two options. The bellows type trap is particularly sensitive, not afraid of freezing, small in size, resistant to overheating, and can be installed at any position. The back pressure ratio is more than 80%, it can discharge non-condensable gas, the membrane box is firm, the service life is long, the maintenance is convenient, and the use range is wide. When the device is just started, the pipeline has low-temperature condensed water, the liquid in the bellows is in a condensed state, and the valve is in the open position. When the temperature of the condensate gradually rises, the filling of the membrane begins to evaporate, the pressure inside the membrane rises, and the diaphragm drives the valve core to move in the closing direction. The trap begins to close before the condensed water reaches the saturation temperature. The bellows controls the valve switch with the change of steam temperature, which acts as a steam blocking effect.

2. Bellows type trap: The valve core stainless steel bellows of the bellows type trap are filled with a liquid whose vaporization temperature is lower than the water saturation temperature. The valve switch is controlled according to the change of steam temperature. The valve is provided with an adjusting bolt, and the use temperature can be adjusted as needed. Generally, the subcooling adjustment range is lower than the saturation temperature of 15 ° C to 40 ° C. The back pressure rate is more than 70%, it is not afraid of freezing, the volume is small, it can be installed at any position, it can discharge non-condensable gas, and has a long service life. When the device is started, the pipeline is cooled and condensed, the liquid in the bellows is in a condensed state, and the valve core is in the open position under the elastic force of the spring. When the temperature of the condensate gradually rises, the filling of the bellows begins to evaporate and expand, the internal pressure increases, the deformation is extended, and the valve core is moved to the closing direction. Before the condensed water reaches the saturation temperature, the trap begins to close, and the steam temperature is controlled to change. Valve switch, steam blocking and drainage.

3. Bimetal trap: The main component of the bimetal trap is the bimetal temperature sensing element, which is heated and deformed with the steam temperature and pushes the valve center to open and close the valve. The bimetal trap is equipped with adjusting bolts, which can be adjusted according to the needs. Generally, the subcooling adjustment range is lower than the saturation temperature of 15 ° C to 30 ° C, the back pressure is greater than 70%, and the non-condensable gas can be discharged. It is small in size, resistant to water hammer, high pressure resistant, and can be installed in any position. Bimetals are fatigued and require frequent adjustments. When the device is just started, the pipeline has low-temperature condensed water, the bimetal is flat, the valve core is under the spring force, and the valve is in the open position. When the temperature of the condensate gradually rises, the bimetal temperature sensing element begins to bend and deform, and pushes the valve core to the closed position. The trap begins to close before the condensate reaches the saturation temperature. The bimetal controls the valve switch with steam temperature change and blocks steam drainage.

3. Thermodynamic type steam traps: According to the principle of phase change, the steam traps rely on different thermodynamic principles of flow rate and volume change when steam and condensate pass, so that different pressure differences are generated above and below the valve plate, and the valve is opened and closed. Since the working power of the thermodynamic steam trap is derived from steam, steam waste is relatively large. The structure is simple, water-resistant, the maximum back is 50%, there is noise, the valve piece works frequently, and the service life is short. Thermodynamic steam traps are thermodynamic (disc), pulsed, orifice plate

1. Thermodynamic steam trap: The thermodynamic steam trap has an active valve plate, which is both a sensitive component and an action actuator. According to the different thermodynamic principles of the flow rate and volume change when steam and condensate pass, the valve plate generates different pressure difference up and down, and drives the valve to open and close the valve. The leakage rate is 3%, and the degree of undercooling is 8°C-15°C. When the device is started, the pipeline is cooled and condensed, and the condensed water pushes the valve plate by the working pressure to discharge quickly. When the condensed water is discharged, the steam is subsequently discharged. Because the volume and flow rate of the steam is larger than the condensed water, a pressure difference is generated between the valve plate and the valve plate is quickly closed under the suction of the steam flow rate. When the valve piece is closed, the valve piece is subjected to pressure on both sides, and the force receiving area under the valve piece is smaller than the upper force receiving area. Since the pressure inside the steam trap chamber is derived from the steam pressure, the force on the valve plate is greater than the lower surface, the valve piece Close tightly. When the steam inside the steam trap chamber cools down into condensed water, the pressure inside the steam chamber disappears. The condensate pushes the valve piece by the working pressure, and the condensed water continues to discharge, and the circulation works intermittently.

2. Disc-type steam-insulated trap: The disc-type steam-insulated trap has the same working principle as the thermodynamic trap, which adds a layer of outer casing to the outside of the steam chamber of the thermodynamic trap. The inner chamber of the outer casing communicates with the steam pipe, and the main steam chamber of the steam trap is insulated 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 trap is tightly closed. When the pipeline produces condensed water, the trap casing cools down, the trap begins to drain; if there is no condensate on the superheated steam line, the trap will not open and the work quality is high. The valve body is alloy steel and the valve core is made of hard alloy. The maximum allowable temperature of the valve is 550 ° C. It is durable and has a long service life. It is a special steam trap for high pressure and high temperature superheated steam.

3. Pulse trap: The pulse trap has two orifices to adjust the valve switch according to the change of vapor pressure drop. Even if the valve completely closes the inlet and outlet, it is connected through the first and second holes, and is always incompletely closed. In the state, the steam continuously escapes and the amount of steam leakage is large. The trap has a high operating frequency, high wear and short life. Small size, water-resistant, can discharge air and saturated temperature water, close to continuous drainage, the maximum back pressure is 25%, so there are few users.

4. Orifice type trap: Orifice type trap is designed to control the displacement of orifices with different pore sizes according to different displacements. The structure is simple, the selection is not suitable, there will be drainage or a large amount of steam running, and it is not suitable for the intermittent production of steam equipment or steam equipment with large fluctuation of condensed water.