Steam trap in steam heating system to play the role of gas drainage, select the appropriate trap, the steam heating equipment to achieve maximum efficiency. In order to achieve the best results, we must conduct a comprehensive understanding of the performance of various types of traps, features. Trap a lot of varieties, each with different properties. The choice of traps, the first choice should be its characteristics to meet the best operation of steam heating equipment, and then consider other objective conditions, so you need to select the trap is correct and effective. Traps to be able to "identify" steam and condensate in order to play the role of gas blocking drainage. "Identifying" steam and condensate is based on three principles: density difference, temperature difference and phase transition. So according to three principles to create three types of traps: classified as mechanical type, thermal type, thermal type. I. Mechanical Traps: Mechanical type, also known as the float type, is the use of condensed water and steam density difference, through the condensation of liquid level changes, so that the float lift valve to open or close, to block steam drainage purposes. Mechanical type of small degree of supercooling traps, free from pressure and temperature changes, the water that is row, no water heating equipment, heating equipment can achieve the best heat transfer efficiency. Maximum back pressure ratio of 80%, high quality workmanship, the production process is the ideal heating device steam trap. Mechanical trap with free float, free half float, lever float, inverted bucket, etc. 1. Free float trap: Free float trap has a simple structure, the internal only a fine moving parts Grinding stainless steel hollow float, both float and opening and closing pieces, non-wearing parts, long service life, "YQ" traps with Y series automatic exhaust device inside the air is very sensitive, can automatically discharge air, work high quality. When the equipment is just started to work, the air in the pipeline is exhausted by the Y series automatic exhaust air device. The low temperature condensate water enters the steam trap, the condensate water level rises, the float rises, the valve opens, the condensate water rapidly discharges and the steam quickly enters Equipment, equipment, rapid heating, Y series of automatic exhaust air temperature of the liquid expansion of the device, automatic exhaust air device is turned off. Traps began to work normally, the float with the condensate level rise and fall, block steam drainage. Free float ball valve seat is always below the liquid level to form a water seal, no steam leakage, energy saving effect. Minimum working pressure 0.01Mpa, from 0.01Mpa to the maximum operating pressure range from the impact of temperature and pressure fluctuations, continuous drainage. To the saturation temperature condensate water, the minimum undercooling is 0 ℃, heating equipment without water, can make the heating equipment to achieve the best heat transfer efficiency. Back pressure rate greater than 85%, is the production of process heating equipment, one of the best trap. 2. Free half-float trap: Free half-float trap Only one half-float bucket is a moving part, opening down, the bucket is the opening and closing pieces, but also the seal. The entire spherical surface can be sealed, long service life, water hammer, no wearing parts, trouble-free, durable, no steam leakage. The back pressure rate is greater than 80%, to the saturation temperature condensate water, the minimum undercooling is 0 ℃, heating equipment without water, can make the heating equipment to achieve the best heat transfer efficiency. When the device is just started, air and low temperature condensate in the pipeline enter the steam trap through the launch tube. The bimetallic emptying element in the valve bounces the bucket open, the valve opens, and the air and low temperature condensate drain rapidly. When the steam enters the bucket, the bucket produces upward buoyancy, while the temperature inside the valve rises, the bimetallic emptying element contracts and the ball is poled toward the valve port and the valve is closed. When the steam inside the bucket becomes condensed water, the bucket loses its buoyancy and sinks, the valve opens and the condensate drains quickly. When the steam enters the barrel again, the valve is closed again, intermittently and continuously. 3. Lever Float Traps: Lever float traps with the same basic characteristics of the free float, the internal structure of the floating ball is connected to the lever to drive the valve heart, with the condensation of the liquid level switch valve. Leveraged float traps use double seats to increase the condensate displacement to achieve a small volume displacement, the maximum hydrophobic capacity of 100 tons / hour, is the ideal large-scale heating equipment traps. 4. Inverted bucket trap: Inverted bucket trap inside is an inverted bucket for the level of sensitive parts, bucket opening down, inverted bucket connected to the valve lever to open the valve lever. Upside-down bucket trap to the air, not afraid of water hammer, anti-fouling performance. Undercooling is small, the leakage rate is less than 3%, the maximum back pressure rate of 75%, more connectors, the sensitivity of free float ball traps. Because inverted bucket steam trap is closed by steam buoyancy valve, working pressure less than 0.1MPA, not suitable for use. When the device is started, air and low temperature condensate in the pipeline enter the steam trap, the inverted bucket falls by its own weight, the inverted bucket connects the lever to drive the valve core to open the valve, and the air and the low-temperature condensed water are quickly discharged. When the steam enters the inverted bucket, the steam of the inverted bucket produces upward buoyancy, and the inverted bucket rises and the connecting lever drives the valve heart to close the valve. Inverted bucket has a small hole, when part of the steam discharged from the hole, the other part of the steam condensate generated, inverted bucket loses buoyancy, by its own weight to the sink, inverted bucket connected to the valve lever to open the valve, cycle Work, intermittent drainage. 5. Combined superheated steam traps: Combined superheated steam traps have two isolated valve chamber, the two stainless steel pipe connected to the upper and lower valve cavity, which is by the float and inverted bucket trap combination, the valve The structure is advanced and reasonable. Under the working conditions of overheating, high pressure and light load, the condensate formed when the superheated steam disappears can be discharged in time, effectively preventing overheated steam leakage and high working quality. The maximum allowable temperature of 600 ℃, the valve body is all stainless steel, the valve seat is carbide steel, long service life, is a steam trap for superheated steam, made two national patents, to fill the gap. When the condensate into the lower chamber, the deputy valve float with the liquid level rise, the float closed into the steam hole. Condensate water pipe up through the main valve cavity, inverted bucket falling by its own weight, driven by the valve core to open the main valve, condensate discharge. When the vice cavity of the condensate water level drops, the float drops with the liquid level, deputy valve open. The steam enters into the inverted bucket from the inlet pipe into the upper main valve cavity, and the inverted bucket produces upward buoyancy. The inverted bucket drives the valve core to close the main valve. When the secondary valve cavity condensate water level then rise, the next cycle began again, intermittent drainage. Second, the thermostatic trap: This type of trap is the use of steam and condensate water temperature sensor temperature caused by the deformation or expansion of the valve opening and closing valve. Subcooling of thermal-static trap is relatively large, the general degree of subcooling is 15 degrees to 40 degrees, it can make use of part of the heat of condensation water, the valve always has high temperature condensate, no steam leakage, significant energy-saving effect . Is in the steam pipe, heating pipelines, small heating equipment, heating equipment, low temperature requirements of small heating equipment, the ideal trap. Thermostatic trap with diaphragm, bellows, bimetal 1. Diaphragm-type trap: diaphragm trap main action element is a metal diaphragm, filled with a gasification temperature ratio Water saturation temperature of the liquid is low, the valve temperature is lower than the saturation temperature of 15 ℃ and 30 ℃ for two options. Diaphragm valve trap response is particularly sensitive, not afraid of freezing, small size, resistance to overheating, can be installed anywhere. Back pressure rate is greater than 80%, can row non-condensable gas, membrane box, long life, easy maintenance, using a wide range. When the device is just started, the pipeline is exposed to low temperature condensate, the liquid in the capsule is in a condensed state, and the valve is in the open position. When the condensate temperature gradually increased, the membrane filled with liquid began to evaporate, membrane pressure within the rise, the diaphragm driven valve heart to close the direction of movement, the condensate to saturation temperature before the trap began to close. Valve box with the steam temperature control valve switch, play the role of gas blocking drainage. 2. Bellows Traps: Bellows Traps Stainless steel bellows filled with a vaporization temperature below the water saturation temperature of the liquid. With the change of steam temperature control valve switch, the valve has adjustment bolts, according to the need to adjust the use of temperature, the general range of subcooling is lower than the saturation temperature of 15 ℃ -40 ℃. Back pressure rate greater than 70%, not afraid of freezing, small size, can be installed anywhere, can row non-condensable gas, long service life. When the device is started, the cooling condensate appears in the pipe, the liquid in the bellows is in a condensed state, and the valve core is in the open position under the spring force. When the condensate water temperature gradually increased, the bellows filled with liquid began to evaporate and expand, the internal pressure increases, deformation elongation, the valve heart to move the direction of closure, before the condensate water saturation temperature, the trap began to shut down, with the steam temperature control Valve switch, steam drainage. 3. Bimetallic trap: The main component of the bimetallic trap is a bimetallic temperature sensing element, which is heated and deformed with the rise and fall of the steam temperature to push the valve to open and close. Bimetallic trap with adjusting bolt can be adjusted according to the need to use the temperature, the general range of subcooling is below the saturation temperature of 15 ℃ -30 ℃, the back pressure rate is greater than 70%, can row non-condensable gas, not afraid of freezing, Small size, can withstand water hammer, high pressure, can be installed anywhere. Bimetal fatigue, need to be adjusted often. When the device is just started, the pipeline appears low temperature condensate, bimetal is flat, the valve core in the spring force, the valve is in the open position. When the condensate water temperature gradually increases, the bimetallic temperature sensor starts to bend and deform and push the valve spool to the closed position. Traps begin to close before the condensate reaches its saturation temperature. Bimetal changes with the steam temperature control valve switch, steam drainage. Thermodynamic steam trap This type of steam trap according to the phase change principle, by steam and condensate flow through the different flow rates and volume changes in thermodynamic principles, so that different pressure from top to bottom valve to drive the valve switch valve. Due to the work force of the thermodynamic steam trap comes from the steam, steam is more wasteful. Simple structure, water hammer, maximum back is 50%, noisy, frequent valve work, short service life. Thermodynamic steam traps have thermal (disc), pulse, orifice plate 1. Thermodynamic steam trap: Thermodynamic steam trap has a movable valve, both sensitive and action pieces. According to the different thermodynamic principles of flow rate and volume change when the steam and condensate pass, the pressure difference is generated on the valve plate to drive the valve switch valve. 3% leakage rate, undercooling 8 ℃ -15 ℃. When the device starts, the pipeline appears condensate cooling, condensate by working pressure to open the valve, the rapid discharge. When the condensate discharge is completed, the steam is subsequently discharged. Due to the large volume of steam and the flow rate of the condensate, the pressure difference is generated above and below the valve, and the valve is rapidly closed under the suction of the steam flow rate. When the valve is closed, the valve is subject to both sides of the pressure, the valve area under the stress is less than the above force area, because the pressure inside the steam trap chamber from the steam pressure, so the valve above the force greater than the following, the valve Close tightly. When the steam trap inside the steam chamber to cool down into condensation water, the pressure inside the chamber disappears. Condensate by working pressure to open the valve, condensate and continue to discharge, work cycle, intermittent drainage. 2. Disc steam insulation trap: Disc steam insulation trap Traps work and thermodynamic trap the same, it is in the thermodynamic steam trap outside the chamber to add a layer of shell. The inner chamber of the shell and the steam pipe are communicated with each other, and the main steam chamber of the steam trap is insulated by the steam of the pipe itself. So that the temperature of the main steam room is not easy to cool, keep the steam pressure, trap tightly closed. When the pipeline produces condensate, trap shell cooling, traps began to drain; superheated steam pipeline if there is no condensation of water, the trap will not open, high-quality work. The valve body is made of alloy steel and the valve core is cemented carbide. The maximum allowable temperature of the valve is 550 ℃. It is durable and long service life. It is a special steam trap for high pressure and high temperature superheated steam. 3. Pulsed steam trap: pulse trap with and two orifice plate according to the steam pressure drop to adjust the valve switch, even if the valve is completely closed inlet and outlet through the first and second holes are connected, always in the incomplete closure State, steam constantly escaped, large amount of steam leakage. The trap action frequency is high, wear powerful, shorter life expectancy. Small size, water hammer, can discharge air and saturated temperature water, close to continuous drainage, the maximum back pressure of 25%, so few users. 4 orifice trap: orifice trap is based on different displacement, the choice of different aperture orifice control drainage purposes. Simple structure, the choice of inappropriate drainage there will be less than or a large number of running steam is not suitable for intermittent production of steam equipment or condensate water volume fluctuations in the use of steam equipment.