Guide to Selecting Steam Traps

Table of operating characteristics for various steam traps. Types of steam traps: float type (open upward), float type (open downward), bimetallic strip type, steam pressure type, liquid expansion type, disc type, pulse type, corrugated type. Drainage methods: continuous drainage, intermittent drainage, continuous drainage, continuous drainage, intermittent drainage, continuous drainage, intermittent drainage, intermittent drainage. Ability to drain saturated water: capable of draining saturated water, capable of draining saturated water; ability to drain saturated water is slightly poor; can only drain water at temperatures below saturation; can only drain water at temperatures below saturation; can only drain water at temperatures below saturation; can only drain water at temperatures below saturation; can only drain water at temperatures below saturation; can only drain water at temperatures below saturation. Ability to remove air: requires an additional venting device; requires an additional venting device; air removal speed is very slow; can remove large amounts of air; can remove large amounts of air; can remove large amounts of air; can remove large amounts of air; requires an additional venting device; air removal speed is very slow. Steam loss: can retain heat, with surface heat dissipation; low steam loss, with surface heat dissipation; low steam loss. Amount of steam required for operation: small amount. Steam loss in the control circuit: small amount. Effect of steam pressure changes on the steam trap: can adapt to large and sudden pressure changes; cannot adapt to large and sudden pressure changes; cannot adapt to large and sudden pressure changes; no issue with large and sudden pressure changes; cannot adapt to large and sudden pressure changes; no issue. Is there a limit on backpressure? Backpressure is 80% of the inlet pressure; backpressure is 80% of the inlet pressure; backpressure is 80% of the inlet pressure. Backpressure needs to be adjusted if it exceeds a certain level; backpressure is 75% of the inlet pressure; backpressure is 75% of the inlet pressure; backpressure is 70% of the inlet pressure; backpressure is 50% of the inlet pressure; backpressure is 25% of the inlet pressure. Can it be used with superheated steam? Corrugated valve type – cannot be used with superheated steam; cannot be used; can be used; cannot be used; cannot be used; cannot be used; can be used; can be used. Is it sensitive to movement? Very sensitive; sensitive; not sensitive; not sensitive; not sensitive; not sensitive; not sensitive; not sensitive. Is it sensitive to water hammer? Not sensitive; not sensitive; not sensitive; not sensitive; not sensitive; not sensitive; not sensitive; not sensitive. Last edited by DAC Junlin Tianxia on 2009-3-2 14:36

Structure and working principle of steam traps: Steam traps serve to prevent steam from entering while allowing water to be drained in steam heating systems. Choosing the right steam trap enables steam heating equipment to achieve maximum efficiency. To achieve the most optimal results, it is necessary to have a comprehensive understanding of the operating performance and characteristics of various types of steam traps. There are many types of pressure relief valves, each with different properties. When selecting a steam trap, it is first necessary to ensure that its properties meet the requirements for optimal operation of steam heating equipment; only after that should other objective factors be considered. This approach ensures that the steam trap chosen is the right one and effective. For a steam trap to function as a vapor barrier and water drain, it must be able to “identify” steam from condensed water. “The detection of steam and condensate is based on three principles: density difference, temperature difference, and phase change. Thus, three types of steam traps were manufactured based on three principles: they are classified as mechanical, thermostatic, and thermodynamic types. I. Mechanical type steam traps: Also known as float-type traps, these utilize the density difference between condensate water and steam; changes in the level of condensate water cause the float to rise or fall, which in turn moves the valve disc open or closed, thereby achieving the purpose of preventing steam from passing while allowing water to flow out. Mechanical steam traps have a low degree of subcooling; they are not affected by changes in operating pressure and temperature. Water is discharged as soon as it appears, preventing water from remaining in the heating equipment, which enables the heating equipment to achieve optimal heat exchange efficiency. With a maximum back pressure ratio of 80% and high operating efficiency, it is the ideal steam trap for heating equipment in manufacturing processes. Mechanical steam traps come in various types, including the free-floating ball type, free semi-floating ball type, lever-ball type, and inverted bucket type. 1. Free-floating ball steam trap: This type of steam trap has a simple structure; it contains only one moving component – a finely ground stainless steel hollow ball that serves both as a float and as the valve element. There are no vulnerable parts, so its service life is very long. The “YQ” series of steam traps are equipped with a Y-series automatic air discharge mechanism, which makes them highly sensitive and capable of automatically discharging air, ensuring high performance. When the equipment starts operating, the air in the pipes is expelled through the Y-series automatic air exhaust device. Low-temperature condensate water enters the drain valve; as the level of this condensate rises, the float rises as well, causing the valve to open and the condensate to be discharged rapidly. Steam then enters the equipment quickly, resulting in a rapid increase in its temperature. The temperature-sensitive fluid in the Y-series automatic air exhaust device expands, which causes the device to shut off. The steam trap begins to function properly; the float rises and falls with the level of condensed water, thereby preventing steam from entering while allowing water to drain. In a free-floating ball type steam trap, the valve seat is always below the liquid level, creating a water seal that prevents steam leakage and results in good energy-saving effects. The minimum operating pressure is 0.01 Mpa; within the range from 0.01 Mpa up to the maximum operating pressure, continuous drainage is possible without being affected by temperature or fluctuations in operating pressure. It can discharge saturated-temperature condensate water, with a minimum subcooling of 0°C; no water remains in the heating equipment, which enables it to achieve optimal heat exchange efficiency. With a backpressure ratio of over 85%, it is one of the most ideal steam traps for heating equipment in manufacturing processes. 2. Free semi-floating ball type steam trap: The free semi-floating ball type steam trap has only one semi-floating ball bucket as the moving component; this bucket is open at the bottom, and it serves both as the valve element and as the sealing element. The entire sphere can be sealed, offering a long service life; it is resistant to water hammer, has no vulnerable components, operates without failures, is durable, and prevents steam leakage. With a backpressure ratio of over 80%, it is capable of removing condensate at saturation temperature; the minimum subcooling degree is 0°C, and no water remains in the heating equipment, thereby enabling the heating equipment to achieve optimal heat exchange efficiency. When the device is first started, the air and low-temperature condensate in the pipeline enter the drain valve through the discharge tube. The bimetallic element inside the valve pushes the ball apart, causing the valve to open and allowing the air and low-temperature condensate to be discharged rapidly. When steam enters the ball tank, the tank experiences an upward buoyant force; at the same time, the temperature inside the valve rises, causing the bimetallic strip in the discharge element to contract. As a result, the ball tank moves toward the valve opening, and the valve closes. When the steam in the drum turns into condensed water, the drum loses its buoyancy and sinks; the valve opens, allowing the condensed water to be discharged rapidly. When steam re-enters the ball tank, the valve closes again, resulting in intermittent and continuous operation. 3. Lever-ball type steam trap: The basic characteristics of the lever-ball type steam trap are the same as those of the free-ball type; its internal structure features a ball connected to a lever that drives the valve core, allowing the valve to open and close as the level of condensed water changes. The lever float type steam trap utilizes dual valve seats to increase the condensate discharge volume, resulting in a compact design with high discharge capacity; its maximum steam discharge rate can reach 100 tons per hour, making it the ideal steam trap for large heating systems. 4. Inverted bucket type steam trap: The interior of an inverted bucket type steam trap features an inverted bucket that serves as the level sensor; the opening of this bucket faces downward, and it is connected to a lever that drives the valve core to open and close the valve. The inverted bucket type steam trap can discharge air, is not sensitive to water hammer, and has good anti-fouling properties. It has a low undercooling degree, with a vapor leakage rate of less than 3% and a maximum back pressure ratio of 75%; it features numerous connecting parts, and its sensitivity is lower than that of a free-floating ball type steam trap. Since the inverted bucket type steam trap closes via the upward buoyancy of steam, it is not suitable for use when the operating pressure difference is less than 0.1 MPa. When the device is first started, air and low-temperature condensate in the pipeline enter the drain valve; the inverted bucket drops due to its own weight, and the lever connected to the bucket drives the valve core to open, allowing the air and low-temperature condensate to be discharged rapidly. When steam enters the inverted bucket, the steam within it generates an upward buoyant force, causing the bucket to rise; this in turn moves the connecting lever and closes the valve. The inverted bucket has a small hole in it; as some of the steam escapes through this hole, the remaining steam turns into condensed water. As a result, the inverted bucket loses its buoyancy and sinks due to its own weight. The lever connected to the inverted bucket then causes the valve core to open, allowing for continuous drainage in a cyclic manner. 5. Combined superheated steam trap: The combined superheated steam trap features two separate valve chambers, which are connected to each other by two stainless steel pipes. It is a combination of a float-type trap and an inverted bucket type trap. Its structure is advanced and rational; it enables timely discharge of the condensate water formed when superheated steam disappears under conditions of superheating, high pressure, and low load, effectively preventing the leakage of superheated steam and ensuring high performance. The maximum allowable temperature is 600°C; the valve body is made of all stainless steel, while the valve seat is made of cemented carbide steel, ensuring a long service life. It is a specialized steam trap for superheated steam, and it holds two **patents, filling a gap in domestic technology. When the condensate enters the lower valve chamber, the float ball of the auxiliary valve rises as the liquid level increases, and the float ball seals off the steam inlet hole. The condensate rises to the main valve chamber through the inlet conduit; the hanging bucket drops due to its own weight, which in turn causes the valve core to open the main valve and allow the condensate to be discharged. When the condensate level in the secondary valve chamber drops, the float descends along with the level, and the secondary valve opens. Steam enters the upside-down bucket inside the upper main valve chamber through the steam inlet pipe; this bucket generates an upward buoyant force, which drives the valve core to close the main valve. When the condensate level in the secondary valve chamber rises again, the next cycle begins, with intermittent drainage. II. Thermostatic type steam traps: These types of steam traps utilize the temperature difference between steam and condensed water to cause a deformation or expansion of the temperature-sensitive element, which in turn drives the valve core to open and close the valve. Thermostatic steam traps have a relatively large degree of subcooling, typically ranging from 15 to 40 degrees. They can make use of part of the sensible heat contained in the condensed water; high-temperature condensed water always remains before the valve, there is no steam leakage, and thus they offer significant energy-saving benefits. It is the ideal steam trap for steam pipes, heat tracing pipelines, small heating devices, heating systems, and small heating devices with low temperature requirements. Thermostatic steam traps come in diaphragm type, bellows type, and bimetallic strip type. 1. Diaphragm type steam trap: The main operating element of a diaphragm steam trap is a metal diaphragm filled with a liquid whose vaporization temperature is lower than the saturation temperature of water. There are two options for the opening temperature: 15°C and 30°C below the saturation temperature. The diaphragm-type steam trap has an extremely sensitive response, is not afraid of freezing, is compact in size, can withstand high temperatures, and can be installed in any location. It has a backpressure ratio of over 80%, is capable of removing non-condensable gases, features a robust diaphragm box, offers a long service life, is easy to maintain, and has a wide range of applications. When the device is first started, low-temperature condensate appears in the pipes; the liquid inside the diaphragm box is in a condensed state, and the valve is in the open position. As the temperature of the condensate water gradually rises, the liquid inside the diaphragm begins to evaporate, causing the pressure inside the diaphragm to increase. This pressure drives the valve core to move in a direction that closes the valve; the check valve starts to close before the condensate water reaches its saturation temperature. The diaphragm box controls the opening and closing of the valve in response to changes in steam temperature, thereby serving to prevent steam from passing through and to drain water. 2. Bellows-type steam trap: The valve element of a bellows-type steam trap is a stainless steel bellows filled with a liquid whose vaporization temperature is lower than the saturation temperature of water. The valve is operated in response to changes in steam temperature; it is equipped with adjustment bolts that allow the operating temperature to be adjusted as needed. Generally, the supercooling range is between 15°C and 40°C below the saturation temperature. With a backpressure ratio of over 70%, it is resistant to freezing, has a small size, can be installed in any location, is capable of removing non-condensable gases, and boasts a long service life. When the device is started, cooling condensate appears in the pipeline; the liquid inside the bellows is in a condensed state, and the valve core remains in the open position due to the elastic force of the spring. As the temperature of the condensate rises, the liquid inside the bellows begins to evaporate and expand, causing an increase in internal pressure. This leads to deformation and elongation of the bellows, which in turn moves the valve core in the direction of closure. The steam trap starts to close before the condensate reaches its saturation temperature; it controls the opening and closing of the valve as the steam temperature changes, thereby preventing steam from passing while allowing water to drain. 3. Bimetallic sheet steam trap: The main component of a bimetallic sheet steam trap is the bimetallic sheet temperature sensor, which deforms when heated as the steam temperature changes, thereby driving the valve core to open and close the valve. Bimetallic sheet-type steam traps are equipped with adjustment bolts that allow the operating temperature to be adjusted as needed. Generally, the degree of subcooling can be set between 15°C and 30°C below the saturation temperature. They can handle non-condensable gases, are resistant to freezing, have a small size, can withstand water hammer, tolerate high pressures, and can be installed in any location. Bimetallic strips are prone to fatigue and require frequent adjustment. When the device first starts up, low-temperature condensate appears in the pipes; the bimetallic strip is flat, and under the force of the spring, the valve core keeps the valve in the open position. As the temperature of the condensate water gradually rises, the bimetallic temperature-sensitive element begins to bend and deform, pushing the valve core toward the closed position. The steam trap begins to close before the condensate reaches its saturation temperature. The bimetallic strip controls the opening and closing of the valve as the steam temperature changes, thereby preventing steam from passing through while allowing water to drain. III. Thermodynamic type steam traps: These types of steam traps operate on the principle of phase change; by utilizing the differences in flow velocity and volume as steam and condensed water pass through, they create a pressure difference between the upper and lower parts of the valve element, which in turn drives the valve to open or close. Since the operating power of thermodynamic steam traps comes from steam, there is significant steam waste. It has a simple structure, is resistant to water hammer, with a maximum back pressure of 50%; it generates noise, the valve disc operates frequently, and its service life is short. Thermodynamic steam traps include the thermodynamic type (disk type), pulse type, and orifice plate type. 1. Thermodynamic steam trap: A movable valve disc is contained within a thermodynamic steam trap; this disc serves both as a sensing element and as the actuating element. Based on the thermodynamic principles related to the differences in flow velocity and volume as steam and condensate pass through, a pressure difference is created above and below the valve disc, which drives the disc to open or close the valve. The vapor leakage rate is 3%, and the subcooling degree is 8°C–15°C. When the device is started, cooling condensate appears in the pipeline; this condensate pushes the valve disc aside due to the operating pressure and is quickly discharged. Once the condensate has been discharged, steam is then released. Since steam occupies more volume and flows at a higher velocity than condensate, this creates a pressure difference above and below the valve disc, causing the disc to close rapidly due to the suction force of the steam flow. When the valve disc is closed, it is subjected to pressure from both sides; the area under the valve disc on which pressure acts is smaller than the area above it. Since the pressure in the steam chamber of the steam trap comes from the steam pressure, the pressure acting on the upper side of the valve disc is greater than that on the lower side, causing the valve disc to close tightly. When the steam in the steam chamber of the check valve cools down to become condensate, the pressure in the chamber is eliminated. The condensate pushes the valve disc open using the operating pressure; it then continues to be discharged, enabling a cyclic operation with intermittent drainage. 2. Disk-type steam-insulated trap: The working principle of the disk-type steam-insulated trap is the same as that of the thermodynamic trap; it features an additional outer shell surrounding the vapor chamber of the thermodynamic trap. The inner chamber of the shell is connected to the steam pipeline, and the steam from the pipeline itself is used to insulate the main steam chamber of the steam trap. This prevents the temperature in the main steam chamber from dropping, maintains the steam pressure, and keeps the drain valve tightly closed. When the shell of the drain valve for condensate water in the pipeline cools down, the drain valve begins to discharge water ； On a superheated steam pipeline, if no condensate is generated, the steam trap will not open, ensuring high operational efficiency. The valve body is made of alloy steel, while the valve core is made of cemented carbide. This valve can withstand a maximum temperature of 550°C; it is durable and has a long service life, making it an ideal steam trap for high-pressure, high-temperature superheated steam. 3. Pulsating steam trap: A pulsating steam trap features two orifice plates that adjust the opening and closing of the valve in response to changes in steam pressure; even when the valve is completely closed, the inlet and outlet remain connected through the first and second small orifices, resulting in an incomplete closure state. As a result, steam continues to escape, leading to high steam leakage. This steam trap has a high operating frequency, suffers from severe wear, and has a short lifespan. It has a small size, is resistant to water hammer, can discharge air and water at saturated temperature, enabling nearly continuous drainage; with a maximum back pressure of 25%, it is rarely used by users. 4. Orifice-type steam trap: The orifice-type steam trap uses orifices of different diameters, selected based on the required drainage volume, in order to control that volume. It has a simple structure; an inappropriate selection can lead to inadequate drainage or excessive steam leakage. It is not suitable for steam-using equipment in batch production or those with large fluctuations in condensate volume

Installation method of steam traps: Whether a steam trap is installed properly has a direct impact on its proper functioning as well as on the production efficiency of the equipment. The steam trap must be installed in accordance with proper installation requirements in order to ensure optimal performance of both the steam trap and the equipment. 1. Before installing the steam trap, it is necessary to purge the pipeline with pressurized steam to remove any debris from within it. 2. A filter should be installed in front of the steam trap to prevent it from being clogged by debris in the pipes, and the filter should be cleaned regularly. 3. Valves should be installed before and after the steam trap to facilitate its maintenance at any time. 4. The flow direction of the condensate water must be in line with the arrow indicator on the steam trap. 5. The drain valve should be installed at the lowest point of the equipment outlet to discharge condensate in a timely manner and prevent vapor lock in the pipes. 6. If there is no space at the lowest point of the equipment to install a steam trap, a check valve (condensate lift fitting) should be installed at the lowest outlet point to raise the condensate level before installing the steam trap, thereby preventing vapor lock. 7. The outlet pipe of the steam trap should not be submerged in water. (If submerged in water, a hole should be drilled at the bend to break the vacuum and prevent sand from being sucked back in.) ) 8. Mechanical steam traps should be installed horizontally. 9. Steam traps should not be installed in series. 10. Each piece of equipment should be equipped with its own drain valve. 11. A supercooled pipe without insulation of more than one meter is required in front of thermostatic steam traps; other types of steam traps should be placed as close as possible to the equipment. 12. When selecting a steam trap for drum-type drying (with siphon tube) equipment, please specify that a steam trap equipped with an anti-steam-locking device should be used to prevent steam locking in the equipment. 13. If condensate is to be recovered after the steam trap, the outlet pipe of the steam trap should be connected to the main pipeline above the recovery main pipe, in order to reduce backpressure and prevent backflow. 14. If condensate is to be recovered after the steam trap, pipelines of different pressure levels should be separated for recovery. 15. The main condensate recovery pipe downstream of the steam trap must not have a slope, as this will increase the back pressure on the steam trap. 16. A check valve should be installed before the condensed water flowing after the steam trap enters the main recovery pipe, to prevent backflow of the condensed water. 17. Install steam traps on the steam pipes; a condensate collection tank should be provided on the main pipe, with its size being close to the radius of the main pipe, and then small pipes should be used to lead the condensate to the steam traps. 18. When a mechanical drain valve is not in use for an extended period, the drain screw should be removed to release the water inside, thereby preventing freezing. 19. If it is detected that the steam trap is leaking steam, it is necessary to drain waste water and clean the filter screen promptly. Regular inspections should be carried out based on actual usage conditions, and any faults should be repaired immediately. It should be inspected at least once a year to remove any impurities inside. Thermostatic valves are considered to be minor components in the entire steam system, but they have a significant impact on the system’s operation and economic efficiency. Therefore, the maintenance and inspection of these valves are also crucial; it is essential to pay due attention to their important role in production processes. Regular maintenance to keep the steam trap in good working condition is essential to achieve optimal energy savings and improved economic benefits.

The three energy-saving functions of steam traps: There are many types of steam traps available today, but their working principle relies on the differences in pressure, temperature, and flow rate between steam and condensed water. Various mechanisms are used to open and close these traps, thereby preventing steam from passing through while allowing water to be drained. It has mainly three energy-saving functions. 　　First, quickly drain the condensate water generated within the steam-using equipment, so as to maintain the heating efficiency of such equipment at its optimal level. This prevents the accumulation of condensate water inside the equipment, ensuring maximum utilization of the steam space available within it; as a result, the highest possible heating efficiency can be maintained on a regular basis. Once steam traps fail to function properly, the accumulation of condensate not only significantly affects the performance of steam-using equipment, but in some cases can even bring production equipment completely to a standstill. 　　Second, quickly discharge the air and low-temperature condensate inside the equipment at startup, thereby reducing the preheating time. When starting to supply steam, both the steam delivery pipes and the equipment that uses steam are filled with air; if this air is not removed, steam cannot be delivered. Furthermore, during the process in which the steam transmission pipelines and steam-using equipment heat up to the steam temperature, the initial low-temperature condensate water generated must also be removed promptly, so that the equipment can operate normally in a short time. This is an important condition for improving production efficiency; especially in batch production scenarios, reducing the preheating time also shortens the duration of each operation, and by increasing the number of operations, output can ultimately be increased. Previously, during warm-up operations, the bypass valve was opened first to discharge initial air and low-temperature condensate; now, with the use of appropriate steam traps, initial air and low-temperature condensate can be discharged automatically, thus saving labor. 　　Third, reduce the steam consumption of the steam trap itself. The so-called steam consumption of the steam trap itself generally refers to steam leakage; it is the sum of the amount of steam required for the trap to operate and the amount lost due to heat dissipation.

This standard applies to the factory inspection and type testing of mechanical, thermostatic, and thermodynamic steam traps (hereinafter referred to as traps). 2 Test apparatus 2.1 The test apparatuses for the operation test, minimum operating pressure test, maximum operating backpressure test, and maximum operating pressure test are shown in Figure 1. 2.2 The test apparatuses for the steam leakage rate test, condensate discharge volume test, drain temperature test, and maximum drain temperature test are shown in Figure 2. 1 2.3 General requirements for the testing apparatus a) The volume of the high-pressure tank shall be not less than 2 m3 ； b) The backpressure tank volume shall be not less than 1 m3 ； c) The volume of the metering tank shall be not less than 0.2 m3 ； d) The accuracy of measuring instruments for temperature, pressure, and weight shall be no less than grade 0.5, the accuracy of timing instruments shall be no less than ±0.2%, and their resolution shall not be greater than 0.1s ； e) All hot pipelines and equipment in the unit shall be insulated. Figure 1-3 Test Methods 3.1 Shell Test a) Test medium: water, kerosene, or other liquids with a viscosity not greater than that of water ； b) Test pressure: 1.5 times the nominal pressure ； c) Medium temperature: Room temperature ； d) Apply a test pressure to the assembled steam trap with its inlet and outlet ends sealed; within the time specified in Table 1, the housing shall show no leaks, and the internal components shall exhibit no residual deformation. Nominal diameter/DN Test duration/s ≤50 >1565～150 >60 Note: When using gases such as steam or air for testing, safety measures must be in place and approval from the relevant authorities is required. 3.2 Operation test: When steam is introduced into the drain valve, it should close; when hot condensate water at a certain load rate is introduced, the drain valve should open (the time required to open varies depending on the type of drain valve), and it should close again after the condensate water has been discharged. At least 3 complete cycles are required for this test to be considered complete. Mechanical steam traps with a sealing pair below the sealed float and a built-in water seal function can be tested using air and water. For a disc-type steam trap when the inlet is in a fully vapor state, the flutter frequency of its valve disc should not exceed 3 times per minute. For thermostatic valves with a large supercooling degree, the closing supercooling degree is not greater than the value specified in the design. 3.3 Minimum operating pressure test: Perform the operation test as specified in 3.2, while gradually reducing the test pressure until it reaches the minimum operating pressure. Throughout the entire test, the steam trap should be able to open and close properly. 3.4 Maximum operating pressure test: Perform the operation test in accordance with the provisions of 3.2, while gradually increasing the test pressure until it reaches the maximum operating pressure. Throughout the entire test, the steam trap should be able to open and close properly. 3.5 Maximum operating backpressure test: Perform the operation test at the maximum operating pressure in accordance with the requirements of 3.2, while gradually increasing the pressure at the outlet of the steam trap until it can no longer open and close properly. The highest outlet pressure at which the steam trap can still open and close properly is the maximum operating backpressure. 3.6 Air discharge capacity test: Air at a pressure not exceeding 0.3 MPa is introduced into the steam trap; the trap should be able to discharge this air. The trap may close briefly for up to 5 minutes, but the duration of this closure shall not exceed 1 minute. 3.7 Drain temperature test: Steam is introduced into the drain valve to close it, and then condensed water at saturated temperature is introduced. If the steam trap cannot open immediately, wait for it to cool down gradually until it opens automatically; the temperature of the inlet condensate at that time is the opening temperature of the trap. Then, the temperature of the condensate water is gradually increased until the steam trap closes automatically; the temperature of the inlet condensate water at the time of closure is the valve closing temperature. 3.8 Steam leakage test: Under the given operating pressure, hot condensate with a load rate of (6±3%) is introduced into the steam trap, along with saturated steam. The condensate that enters the steam trap is collected in a metering tank of specified capacity, and the steam leakage rate is calculated using the heat balance method. The test method for steam leakage rate is specified in Appendix A. 3.9 Heat condensate discharge test: The heat condensate discharge is the weight of heat condensate discharged per unit time, measured under a certain pressure difference and condensate temperature. The heat condensate flow rate at different pressure differences should be measured at the same subcooling. Under normal circumstances, the hot condensate discharge test allows the outlet of the steam trap to be connected to the atmosphere. The test method for hot condensate discharge shall be in accordance with the provisions of Appendix B. Note: Items 3.3 to 3.8 above do not apply to pulse and orifice type steam traps.

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