Spence AeraValve AV13

**Spirax Sarco AV13 Air Vent Valve, Spirax Sarco AV13 Brass Air Vent Valve** **Spirax Sarco Air Vent Valve** After a period of closure in the pipeline, air fills the pipeline before steam enters. Air and other non-condensable gases can also enter the pipeline along with steam. Compared to steam, the proportion of these non-condensable gases is very small. Unless measures are taken to expel them, these non-condensable gases will accumulate in the steam pipeline and heat exchange space after steam condenses. The consequence of not removing air is prolonged startup time, reduced equipment efficiency, and diminished performance of the process. The presence of air in the steam system also affects the system's temperature. Air has its own pressure throughout the system, and when combined with the steam pressure, it constitutes the total pressure of the system. Therefore, the actual steam pressure and temperature will be lower than the pressure and corresponding temperature indicated by the pressure gauge, which displays the pressure of the steam/air mixture. More importantly, air affects the heat transfer efficiency. A 1mm thick air film has the same thermal resistance as a 25mm thick water film, as well as a 2mm thick iron plate and a 15mm thick copper wall. Therefore, air venting is crucial for any steam system. The air vent valve in the steam system (operating on the same principle as a thermal static steam trap) should be placed above the condensate water level, allowing only the steam/air mixture to reach the air vent valve. The installation position is at the end of the steam main. The gas discharge port of the air vent valve should be connected to a safe location. In practical applications, if the condensate water pipe can flow by gravity to an opening box, it is possible to connect the exhaust pipe to the condensate water pipe. In addition to installing the air vent valve at the end of the main pipe, it should also be installed in the following locations: parallel to the inverted bucket trap, or in some cases, parallel to the thermodynamic trap. These traps have poor air venting performance during startup. In particularly harsh steam spaces (e.g., opposite the steam entering a jacketed kettle). In large steam spaces where the steam/air mixture significantly affects process quality (such as high-pressure sterilizers). **Reducing Heat Loss** Even after the warm-up process of the steam main is complete, steam will continue to condense due to radiative heat loss. The condensation rate depends on steam temperature, ambient temperature, and insulation efficiency of the pipeline. To ensure the steam distribution system is efficient, appropriate measures must be taken to minimize heat loss. The economical insulation thickness is determined by the following factors: installation cost, energy carried by the steam, pipe diameter, and pipe temperature. When insulating outdoor pipelines, humidity and wind speed must also be considered. The effectiveness of most insulation materials depends on the small air pockets contained in inert materials such as mineral wool, fiberglass, or calcium silicate. Typically, aluminum-jacketed fiberglass, aluminum-jacketed mineral wool, and calcium silicate are used. It is crucial that the insulation material does not deform or become waterlogged. Proper mechanical protection and waterproofing are necessary, especially for outdoor installations. Heat loss from steam pipes dissipating to water or humid insulation materials can be up to 50 times greater than heat loss to air. Therefore, it is particularly important to protect steam pipes installed on waterlogged surfaces or within pipelines from being submerged. Similarly, care should be taken to protect insulation layers from damage by ladders or other objects and to prevent rainwater intrusion. In addition to safety valves, all heated parts of the steam system require insulation. This includes all main pipe connection flanges, valves, and other fittings. Insulation should be removed from both sides of the connecting flange to expose the bolts, leaving space for maintenance. This is equivalent to a 0.5m length of exposed pipe. Fortunately, prefabricated insulation covers for connection flanges and valves are widely used today. These are typically supplied with fasteners, making it easy to remove the insulation cover during maintenance. **Heat Transfer Calculation** Calculating heat loss from pipelines is very complex and time-consuming, and we often assume that we know some vague data about wall thickness, heat transfer coefficients, and various export constants, but in reality, this data can be quite uncertain. The derivation of these calculation formulas goes beyond the scope of this section, but relevant information can be found in any thermodynamics textbook. Additionally, our engineers can use various calculation software. Therefore, pipeline heat loss can refer to Table 10.5.1 and a simple formula (Formula 2.12.2). The table assumes an ambient temperature between 10 and 21°C, considering the heat loss of horizontal pipes at different steam pressures and pipe diameters. **Our company also supplies similar products: Spirax Sarco AV13 Air Vent Valve, Spirax Sarco AE30 Air Vent Valve, Spirax Sarco Air Vent Valve.**