Principle of drain valve structure of drain valve

The steam trap is used in the steam pipe network and equipment, which can automatically discharge the condensed water, air and other non condensed gases The steam trap plays a role of blocking steam and drainage in the steam heating system Selecting a suitable steam trap can make the steam heating equipment reach Zui high working efficiency In order to achieve the ideal effect of Zui, it is necessary to have a comprehensive understanding of the performance and characteristics of various types of traps According to the different working principles of steam trap, the steam trap can be divided into the following three types: 1 Mechanical type: acting on the change of the condensed water level in the steam trap, including: floating ball type: the float is a closed hollow ball Open up float type: the float is a bucket type with opening up 3 Open downward float type: the float is the bucket type with the opening downward 2 Thermal static type: it acts according to the change of liquid temperature, including bimetallic sheet: the sensitive element is bimetallic sheet Steam pressure type: sensitive components are bellows or ink cartridges, filled with volatile liquid 3 Thermal power type: act on the change of the thermal dynamic mechanical properties of the liquid Disc type: due to the different flow rates of liquid and gas under the same pressure, different dynamic and static pressures are generated to drive the disc valve plate to act Pulse type: due to the different temperature of condensate through the two pole series orifice plate, sitting between the two pole orifice plate of different pressure, drive the valve disc action There are many kinds of traps, each with different performance It is necessary to be able to "identify" steam and condensate, so as to play a role of steam blocking and drainage The "identification" of steam and condensate is based on three principles: density difference, temperature difference and phase change According to the three principles, three types of traps are made: mechanical type, thermal static type and thermal dynamic type Mechanical type drain valve: mechanical type, also known as float type, is to use the density difference between condensate and steam, through the change of condensate liquid level, make the float lift to drive the valve disc to open or close, so as to achieve the purpose of steam blocking and drainage The mechanical type drain valve has small subcooling and is not affected by the working pressure and temperature change When there is water, it will be discharged There is no water in the heating equipment, which can make the heating equipment achieve Zui heat exchange efficiency The large back pressure ratio of Zui is 80% and its working quality is high It is an ideal drain valve for Zui heating equipment in production process Mechanical traps are free floating ball type, free semi floating ball type, lever floating ball type, inverted bucket type, etc 1 Free floating ball trap: the structure of free floating ball trap is simple There is only a stainless steel hollow floating ball with fine grinding of moving parts inside It is not only a float but also a opening and closing part It has a long service life YQ trap is equipped with Y Series automatic air evacuation device, which is very sensitive, can automatically exhaust air and has high working quality When the equipment is just started, the air in the pipeline is discharged through the Y-series automatic air exhaust device, the low-temperature condensate enters the drain valve, the liquid level of the condensate rises, the floating ball rises, the valve is opened, the condensate is discharged quickly, the steam enters the equipment quickly, the equipment heats up quickly, the temperature sensing liquid of the Y-series automatic air exhaust device expands, and the automatic air exhaust device is closed The drain valve starts to work normally, the floating ball rises and falls with the condensate level, and the steam is blocked for drainage The valve seat of the free floating ball type drain valve is always below the liquid level, forming a water seal, no steam leakage, and good energy saving effect Zui small working pressure is 0.01Mpa, from 0.01Mpa to Zui high working pressure range is not affected by temperature and working pressure fluctuations, and continuous drainage is carried out It can drain saturated temperature condensate, Zui small subcooling degree is 0 ℃, there is no water in the heating equipment, which can make the heating equipment achieve Zui good heat exchange efficiency The back pressure rate is more than 85%, which is one of the ideal traps for Zui 2 Free semi floating ball type drain valve: only one semi floating ball type ball barrel of the free semi floating ball type drain valve is a movable part, with the opening downward, the ball barrel is both the opening and the closing part and the sealing part The whole spherical surface can be sealed, with long service life, water hammer resistance, no wearing parts, no fault, durable and no steam leakage When the back pressure ratio is more than 80%, the saturated temperature condensate can be discharged When the Zui low degree of supercooling is 0 ℃, there is no water in the heating equipment, which can make the heating equipment achieve Zui optimal heat exchange efficiency When the device is just started, the air and low-temperature condensate in the pipeline enter the drain valve through the launching pipe, the bimetal emptying element in the valve pops the ball barrel open, the valve is opened, and the air and low-temperature condensate are discharged rapidly When the steam enters the ball barrel, the ball barrel will generate upward buoyancy At the same time, the temperature in the valve will rise, the bimetal emptying element will contract, the ball poke will float to the valve port, and the valve will be closed When the steam in the drum becomes condensed water, the drum loses buoyancy and sinks down The valve opens and the condensed water is discharged quickly When the steam enters the ball barrel again, the valve is closed again, intermittent and continuous operation 3 Rod floating ball type drain valve: the basic characteristics of the lever floating ball type drain valve are the same as that of the free floating ball type The internal structure is that the floating ball connects the lever to drive the valve core, and the valve is opened and closed with the rise and fall of the condensate level The lever floating ball type drain valve uses double valve seats to increase the condensate displacement, which can achieve small volume and large displacement, and Zui's large drainage capacity can reach 100 tons / hour It is an ideal drain valve for large heating equipment Zui 4 Inverted bucket type drain valve: inside the inverted bucket type drain valve is an inverted bucket which is a liquid level sensitive part The opening of the bucket is downward The connecting lever of the inverted bucket drives the valve center to open and close the valve Inverted bucket drain valve can exhaust air, not afraid of water hammer, good anti pollution performance The subcooling is small, the steam leakage rate is less than 3%, the Zui large back pressure rate is 75%, there are many connections, and the sensitivity is not as good as the free floating ball type drain valve Because the inverted bucket drain valve is closed by the upward buoyancy of steam, it is not suitable for selection when the working pressure difference is less than 0.1MPa When the device is just started, the air and low-temperature condensate in the pipeline enter into the drain valve, the inverted bucket falls by its own weight, the connecting lever of the inverted bucket drives the valve core to open the valve, and the air and low-temperature condensate are discharged rapidly When the steam enters the inverted bucket, the steam of the inverted bucket will generate upward buoyancy, and the rising connecting lever of the inverted bucket will drive the valve core to close the valve A small hole is opened on the inverted bucket When some steam is discharged from the small hole, the other steam generates condensate, the inverted bucket loses its buoyancy and sinks by its own weight The connecting lever of the inverted bucket drives the valve core to open the valve, circulates and discharges water intermittently 2 Thermal static type drain valve: this type of drain valve uses the temperature difference between steam and condensate to cause the transformation or expansion of temperature sensing elements to drive the valve core to open and close The supercooling degree of the thermal static steam trap is relatively large, generally it is 15 to 40 degrees It can make use of part of the sensible heat in the condensate There is always high-temperature condensate in front of the valve, no steam leakage, and the energy-saving effect is significant It is an ideal drain valve for Zui on steam pipe, tracing pipe, small heating equipment, heating equipment and small heating equipment with low temperature requirements There are three types of thermostatic traps: bellows, bellows and bimetallic 1 Bellows trap: the main action element of bellows trap is metal bellows, which is filled with a liquid whose gasification temperature is lower than the saturation temperature of water There are two options: the opening temperature is 15 ℃ lower than the saturation temperature and the opening temperature is 30 ℃ The response of the bellows type drain valve is very sensitive, not afraid of freezing, small volume, heat resistance, any position can be installed The back pressure rate is more than 80%, which can discharge non condensable gas The membrane box is solid, with long service life, convenient maintenance and wide range of use When the device is just started, there is low-temperature condensate in the pipeline, the liquid in the capsule is in the state of condensation, and the valve is in the open position When the temperature of the condensate gradually increases, the liquid filled in the membrane closing starts to evaporate, and the pressure inside the membrane closing rises The diaphragm drives the valve center to move towards the closing direction Before the condensate reaches the saturation temperature, the drain valve starts to close The membrane box controls the valve switch with the change of steam temperature, which plays the role of steam blocking and drainage 2 Bellows type drain valve: the stainless steel bellows of the valve core of the bellows type drain valve is filled with a liquid whose vaporization temperature is lower than the water saturation temperature Control the valve switch with the change of steam temperature The valve is equipped with adjusting bolts, which can adjust the service temperature as required Generally, the adjustment range of subcooling is 15 ℃ - 40 ℃ lower than the saturation temperature The back pressure rate is more than 70%, not afraid of freezing, small size, can be installed at any position, can discharge non condensing gas, long service life When the device is started, there is cooling condensate in the pipeline, the liquid in the bellows is in the state of condensation, and the valve core is in the open position under the spring force When the temperature of condensate increases gradually, the liquid filled in the bellows starts to evaporate and expand, the internal pressure increases, the deformation and elongation drive the valve center to move towards the closing direction Before the condensate reaches the saturation temperature, the drain valve starts to close, and the valve switch is controlled with the change of steam temperature to prevent the steam from draining 3 Bimetallic steam trap: the main component of bimetallic steam trap is bimetallic temperature sensing element, which is heated and deformed with the rise and fall of steam temperature, and pushes the valve core to open and close the valve Bimetal type steam trap is equipped with adjusting bolts, which can adjust the use temperature as required Generally, the adjustment range of supercooling is 15 ℃ - 30 ℃ lower than the saturation temperature, and the back pressure rate is more than 70% It can discharge non condensing gas, not afraid of freezing, small size, water hammer resistance, high pressure resistance, and can be installed at any position Bimetallic sheet has fatigue and needs to be adjusted frequently When the device is just started, there is low-temperature condensate in the pipeline, the bimetal sheet is flat, the valve core is in the open position under the spring force When the temperature of the condensate increases gradually, the bimetal temperature sensing element begins to bend and deform, and pushes the valve core to the closed position Before the condensate reaches saturation temperature, the drain valve starts to close Bimetallic sheet controls the valve switch with the change of steam temperature to prevent steam and drain water 3 Thermal power type steam trap: according to the principle of phase change, this kind of steam trap depends on the different thermodynamic principles of the flow rate and volume change when the steam and condensate pass through, so as to generate different pressure difference between the upper and lower parts of the valve plate, and drive the valve plate to open and close the valve Because the working power of the thermal power drain valve comes from steam, the steam waste is relatively large The utility model has the advantages of simple structure, water hammer resistance, large back of Zui of 50%, noise, frequent operation of valve plate and short service life Thermal power type steam trap has thermal power type (disc type), pulse type and orifice plate type 1 Thermal power type steam trap: there is a movable valve plate in the thermal power type steam trap, which is not only a sensitive part but also an action executive part According to the different thermodynamic principles of the flow rate and volume change of steam and condensate passing through, different pressure difference is generated between the upper and lower parts of the valve plate, which drives the valve plate to open and close the valve The steam leakage rate is 3%, and the subcooling degree is 8 ℃ - 15 ℃ When the device is started, there is cooling condensate in the pipeline, which is pushed open by the working pressure to discharge rapidly When the condensate is discharged, the steam is discharged later Because the volume and flow rate of the steam is larger than that of the condensate, the pressure difference between the upper and lower parts of the valve plate is generated, and the valve plate is closed rapidly under the suction of the steam flow rate When the valve plate is closed, the pressure on both sides of the valve plate and the stress area under the valve plate