Millions of solenoid valves are in service throughout the world and have been installed with threaded connections, either directly into pipe sections or through couplings that allow the valve to be dismounted for servicing or replacement. As line sizes increase above 1” and definitely above 2”, the complication of threaded connections for mounting the valve and the cost of the couplings if used, make it easier to use flanges.
Instead of male or female threads, a flanged connection mates to an identical flange with a flat gasket sandwiched in between and compressed by bolts that pass through both flanges. This arrangement makes a very good seal and allows the ease of installation and disassembly without affecting the pipework. High pressure flanges may have ring joint seals rather than flat gaskets but this is normally outside of the pressure range of solenoid valves with the exception of special build items.
Although there are many standards throughout the world to enable flange interchangeability, the most common are the ANSI B16.5 imperial sized flanges such as ANSI 150, ANSI 300 or the metric PN16, PN40. These flanges are defined by pressure classes and it is usual to have the flange rating above or equal to the valve rating. There are some cases where a solenoid valve may have a higher pressure rating that the flange it mounts to and in that case, the flange and pipe rating will define the maximum operating pressure, not the valve. Equally a solenoid valve may have a much lower pressure rating than the flange and then the valve is the limiting factor for pressure testing rather than the flanged connection or pipe schedule thickness.
Where the flanges meet and the gasket covers the face, the flange standard will define if the gasket covers the full face of the flange including around the bolt holes or a reduced area not including the bolt holes. The reduced area is on a machined raised face (RF) so that when the flanges are compressed, it is only the mating surfaces that meet the gasket. This can easily be seen on a completed joint as if it is an RF type, there will be a narrow gap around the joint where the bolts can be seen passing through. On a flat face joint (FF) there is no gap and the gasket should be slightly extruded around the circumference of the joint to indicate good compression.
Most flanged solenoid valves are produced with metric PN sized flanges as standard but some manufacturers do offer ANSI version on request.
Flanged solenoid valves can be supplied from ½” (DN15) up to 12” (DN300) and sometimes even larger than that. The flanges are often the same material as the solenoid valve body but this does not have to be such as the case where plastic flanges or another material is specified. Mismatched materials can make the valve more expensive if it is based on a cast design. Machined valve bodies provide more scope for customised connections.
The most common flanged valves are 2 way (2/2) and either normally closed or normally open. Three way (3/2) are less common but still available in a wide range of sizes. Valves for natural gas isolation are commonly available with flanged connections from 2” to 8” although we can offer a much wider size range than this, especially where higher pressures are need and PN40 flange ratings are required. Water or cooling systems are another common use for flanged solenoid valves and can be supplied in bronze, brass, stainless steel or other materials depending on the application. Many of these flanged solenoid valve can be supplied with ATEX certification for use in potentially explosive atmospheres.
Flanged gate and globe valves are designed and manufactured to international standards that specify a lay length according to the line size in order that valves are readily interchangeable. Solenoid valves tend to be more compact than manual valves and their manufacturers do not follow the face to face sizing dimensions standards. In this regard, flanged solenoid valves are not often capable of being swapped between manufacturers and fitting in the same lay length. The options here are either to adjust the pipe length and lay length to suit the new valve or accept that a replacement from the original valve manufacturer is the only choice. This however can lead to issues since manufacturers change their specifications as they improve or revise their products and this can still mean that the lay lengths change when new casting moulds are produced. If maintaining the same lay length as a previous valve is important, please make us aware of that so that we can find the best fit as well as performance.
Please tell us your requirements for flanged solenoid valves so that we can offer the best solution for your application from the many different models available to us.
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