Structure and working principle of trap

Structure and working principle of trap:

　　Steam trap plays a role of steam resistance and drainage in the steam heating system. Selecting the appropriate steam trap can make the steam heating equipment reach high working efficiency of Z. In order to achieve ideal results, it is necessary to have a comprehensive understanding of the performance and characteristics of various types of traps.

There are many varieties of traps with different performance. When selecting trap, first select its characteristics can meet the Z good operation of steam heating equipment, and then consider other objective conditions, so you choose the trap you need is correct and effective.

Steam trap to be able to "identify" the steam and condensate, to play the role of steam drainage. The "recognition" of steam and condensate is based on three principles: a difference in density, a difference in temperature, and a phase transition. Therefore, three types of traps are manufactured according to three principles: mechanical type, thermostatic type and thermodynamic type.

I. mechanical trap:

Mechanical type also known as float type, is the use of condensate and steam density difference, through the condensate level change, float lift drive valve disc open or close, to achieve the purpose of blocking steam drainage. Mechanical trap of low temperature, not affected by working pressure and temperature changes, water is discharged, no water in the heating equipment, heating equipment to achieve heat efficiency. Z big back pressure rate is 80%, high working quality, is the production process heating equipment ideal trap.

Mechanical trap has free float ball type, free half float ball type, pole float ball type, inverted lift (buy) bucket type, etc

1. Free-floating ball type steam trap:

Free float type steam trap structure is simple, the internal only a moving parts fine grinding stainless steel hollow float, float is open and close parts, no vulnerable parts, long service life, trap with Y series automatic exhaust air device, very sensitive, can automatically exhaust air, high quality of work.

Equipment has just started work, air in the pipe after Y series automatic air discharge device, low temperature water into the steam trap, water level rise, the float rises, the valve opens and the condensate discharge rapidly, steam quickly into equipment, equipment rapidly, Y series automatic air discharge device of liquid thermal expansion, automatic air discharge equipment shut down. Trap began to work normally, floating ball with condensate level rise and fall, steam drainage. The seat of the free float trap is always below the liquid level, forming a water seal, no steam leakage, good energy saving effect. Z small working pressure 0.01Mpa, from 0.01Mpa to Z high operating pressure range is not affected by temperature and working pressure fluctuations, continuous drainage. It can discharge the condensate water at the saturation temperature, and the Z small subcooling degree is 0℃. There is no water in the heating equipment, which can make the heating equipment reach the heat exchange efficiency. Back pressure rate is more than 85%, is one of the production process heating equipment ideal trap.

2. Free semi-floating ball steam trap:

Free half float ball steam trap only a half float ball ball bucket for the moving parts, opening down, the ball bucket is the opening and closing parts, is the sealing parts. The whole sphere can be sealed, the service life is very long, can resist water hammer, no wearing parts, no fault, durable, no steam leakage. The back pressure rate is more than 80%, which can discharge the condensate water at the saturated temperature, and the Z small subcooling degree is 0℃. There is no water storage in the heating equipment, which can make the heating equipment achieve the heat exchange efficiency.

When the device is just started, the air and low-temperature condensate in the pipeline enter the trap through the launching pipe, and the bimetallic strip empting element in the valve bounces the ball barrel, the valve opens, and the air and low-temperature condensate are quickly discharged. When the steam enters the ball barrel, the ball barrel generates upward buoyancy. At the same time, the temperature in the valve increases, the bimetallic strip empties the element shrinks, the ball plunges to the valve port, and the valve closes. When the steam in the bucket becomes condensed water, the bucket loses buoyancy and sinks, the valve opens and the condensed water is quickly discharged. When the steam reenters the barrel, the valve is closed again, intermittently and continuously.

3. Lever float ball type steam trap:

The basic characteristics of the rod float type steam trap are the same as that of the free float type. The internal structure is that the float is connected with the lever to drive the valve center, and the valve is switched on and off with the rise and fall of the liquid level of the condensate. With double seats to increase the condensate displacement, the rod float trap can achieve a small volume with a large displacement, and Z with a large hydrophobic capacity of 100 tons/hour. It is an ideal trap for large heating equipment.

4. Inverted hanging (set) bucket trap:

Inside the inverted bucket trap is an inverted bucket for liquid level sensitive parts. The bucket opens downward and the inverted bucket is connected to the lever to drive the valve center to open and close the valve. Inverted bucket trap can exhaust air, not afraid of water, anti - pollution performance. The subcooling degree is small, the steam leakage rate is less than 3%, the Z big back pressure rate is 75%, the connection is more, the sensitivity is not as free floating ball trap. Because the inverted hanging (buy) bucket trap is closed by steam upward buoyancy valve, the working pressure difference is less than 0.1mpa, is not suitable for selection.

When the device is just started, the air and low-temperature condensate in the pipeline enter the trap, and the inverted bucket falls under its own weight. The inverted bucket is connected with a lever to drive the valve center to open the valve, and the air and low-temperature condensate are quickly discharged. When the steam enters the inverted bucket, the steam from the inverted bucket generates upward buoyancy, and the inverted bucket rises to connect the lever to drive the valve core to close the valve. There is a small hole in the inverted bucket. When a part of the steam is discharged from the hole and another part of the steam produces condensate water, the inverted bucket loses its buoyancy and sinks by its own weight. The inverted bucket is connected with a lever to drive the valve center to open the valve and circulates for intermittent drainage.

5. Combined superheated steam trap:

Combined superheated steam trap has two isolation valve cavity, two stainless steel tubes connected by upper and lower valve chamber, it is by the ball float and upside-down (buy) barrels of the combination of steam trap, the valve structure of advanced and reasonable, in the heat, high pressure and small load working conditions, to be able to timely discharge superheat disappear when the formation of the condensate, effectively prevent leakage of superheated steam, high quality of work. Z high allowable temperature is 600℃, the valve body is all stainless steel, the seat is hard alloy steel, the service life is long, is the superheated steam trap special, obtained two national patents, filled the domestic blank.　

When the condensate enters the lower valve chamber, the float ball of the auxiliary valve rises with the liquid level, and the float ball closes the inlet pipe hole. The condensate rises to the main valve chamber through the inlet pipe, and the inverted bucket falls by its own weight to drive the valve center to open the main valve and discharge the condensate. When the condensate level of the secondary valve cavity drops, the float drops with the liquid level and the secondary valve opens. Steam from the inlet pipe into the inverted bucket in the upper main valve chamber, the inverted bucket produces upward buoyancy, and the inverted bucket drives the valve center to close the main valve. When the condensate level of the auxiliary valve chamber rises again, the next cycle cycle begins again and discontinuous drainage occurs.

Ii. Thermostatic trap:

This kind of trap is the use of steam and condensate water temperature difference caused by the variation of the temperature element or expansion of the valve heart open and close valve. Thermal static trap of the degree of undercooling is relatively large, the general degree of undercooling is 15 degrees to 40 degrees, it can use a part of the condensate sensible heat, there is always high temperature condensate before the valve, no steam leakage, energy saving effect is significant. It is an ideal trap in steam pipeline, heat tracing pipeline, small heating equipment, heating equipment, small heating equipment with low temperature requirements.

Thermostatic type trap has bellows, bellows, bimetal plate type

1. Bellows trap:

The main action element of the bellows trap is a metal bellows filled with a liquid whose gasification temperature is lower than the saturation temperature of water. There are two options for the valve opening temperature lower than the saturation temperature of 15℃ and 30℃. Bellows trap of the response is particularly sensitive, not afraid of cold, small volume, heat resistance, any position can be installed. The back pressure rate is more than 80%, it can discharge non-condensing gas, the membrane box is firm, the service life is long, the maintenance is convenient, the use range is very wide.

When the device was just started, condensate water at low temperature appeared in the pipeline, the liquid in the membranous box was in the state of condensation, and the valve was in the open position. When the temperature of condensed water gradually increases, the liquid filling in the membrane will start to evaporate, and the pressure in the membrane will rise. The diaphragm will drive the valve to move in the closing direction. Before the condensed water reaches the saturation temperature, the trap will start to close. The valve switch is controlled by the membrane box with the change of steam temperature to prevent steam drainage.

2. Bellows trap:

Bellows trap valve core stainless steel bellows filled with a liquid vaporization temperature below the water saturation temperature. With the change of steam temperature control valve switch, the valve is equipped with adjustment bolts, according to the need to adjust the service temperature, the general adjustment range of supercooling temperature is lower than the saturation temperature 15℃-40℃. Back pressure rate is more than 70%, not afraid of freezing, small size, can be installed at any position, can discharge condensate gas, long service life.

When the device is started, there will be cooling condensate in the pipeline, the liquid in the bellows is in the state of condensation, and the valve center is in the open position under the spring force. When the condensate water temperature gradually increased, the liquid in the bellows began to evaporate and expand, the internal pressure increased, deformation elongation, drive the valve center to move to the direction of closure, before the condensate water reached the saturation temperature, the trap began to close, with the change of steam temperature control valve switch, steam drainage.

3. Bimetal plate steam trap:

The main component of bimetallic sheet trap is the bimetallic sheet temperature sensing element, with the rise and fall of the steam temperature heat deformation, push the valve center switch valve. Bimetal plate trap is equipped with adjustment bolts, according to the need to adjust the service temperature, the general adjustment range of supercooling is lower than the saturation temperature of 15℃-30℃, the back pressure rate is more than 70%, can discharge non-condensing gas, not afraid of freezing, small volume, water hammer resistance, high pressure resistance, any position can be installed. Bimetallic sheets are fatiguing and require frequent adjustment.

When the device is just started, there will be condensate water at low temperature in the pipeline. The bimetallic sheet is flat, and the valve is in the open position under the spring force of the valve heart. When the temperature of condensed water gradually increases, the bimetallic temperature sensing elements begin to bend and deform, and push the valve center to the closed position. Before the condensate reaches the saturation temperature, the trap begins to close. Bimetallic sheet with steam temperature change control valve switch, steam drainage.

Three. Thermal power trap

This kind of trap according to the principle of phase transition, steam and condensate through the flow rate and volume change of different thermodynamic principles, so that the valve plate up and down to produce different pressure difference, drive the valve plate to open and close the valve. Because the thermal power trap's working power comes from the steam, so the steam waste is larger. Simple structure, water resistance, Z big back of 50%, noise, valve plate work frequently, short service life.

Thermal power trap has thermal power type (disc type), pulse type, hole plate type --

1. Thermal power trap:

There is a movable valve disc in the thermal power trap, which is both sensitive and actuating. According to the steam and condensate through the flow rate and volume change of different thermodynamic principles, so that the valve plate up and down to produce different pressure difference, drive the valve plate to open and close the valve. The steam leakage rate is 3%, and the subcooling temperature is 8℃-15℃.

When the device starts, there will be cooling condensate in the pipeline. The condensate will push the valve plate by the working pressure and 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 is generated, and the valve is closed quickly under the suction of the steam flow rate. When the valve plate is closed, the pressure on both sides of the valve plate, the stressed area under the valve plate is less than the stressed area above, because the pressure in the steam trap chamber is from the steam pressure, so the pressure on the valve plate is greater than the pressure below, the valve plate is closed tightly. When the steam in the steam trap chamber cools to condensate, the pressure in the chamber disappears. The condensate pushes the valve plate by the working pressure, the condensate continues to discharge, circulates the work, and discharges the water intermittently.

2. Disc type steam insulation trap:

The working principle of disc type steam insulation trap is the same as that of thermal power trap. It adds a shell to the steam outside of the thermal power trap. The inner chamber of the shell is connected with the steam pipe, and the main steam chamber of the trap is insulated with the steam of the pipe itself. Make the main chamber temperature is not easy to cool down, maintain steam pressure, trap closed tightly. When the pipeline condenses, the trap shell cools and the trap begins to drain. If there is no condensate in the superheated steam pipeline, the trap will not open, the work quality is high. The valve body is alloy steel, the valve core is cemented carbide, the valve Z high allowed temperature of 550℃, durable, long service life, is high pressure, high temperature overheating steam trap.

3. Pulse trap:

Pulse trap has two orifice plates to 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 D one and D two small holes. The valve is always in a state of incomplete closure. The trap action frequency is very high, severe wear, short life. Small size, water shock resistance, can expel air and saturated temperature water, close to continuous drainage, Z large back pressure of 25%, so few users.

4. Orifice plate trap:

Orifice plate trap is based on different displacement, the choice of different aperture orifice plate to control the displacement of the purpose. The structure is simple, the choice is not suitable will appear less than discharge or a large number of steam running, not suitable for intermittent production of steam equipment or condensate water fluctuation of steam equipment.