How to determine the valve connection method for small pipe diameters
Thread Content
The outer diameter of the sanitary-grade pipes specified in current DIN standards is 12 mm or 10 mm, with a wall thickness of 1 mm. The valves used on these pipes are ball valves and diaphragm valves; according to the PID specifications, ball valves are to be welded together while diaphragm valves are to be connected by threading. The manufacturer states that it is difficult to create threads on pipes with a wall thickness of 1 mm, and asks whether it is possible to change the connection method from threading to welding Additionally, how are the connection methods for various valves determined?
For small tubes of about 10 mm in diameter, the valves are welded on. A wall thickness of 1mm does make it difficult to thread bolts; the original poster should consider using welding instead.
Tubes with small diameters can also be connected by threads; have you never seen the pressure transfer tube of a pressure gauge? The small tubes and valve connections are welded; the valves are connected by threads
Diaphragm valves require frequent replacement of their internal components, right? In that case, threads are still the better option
Quick clamps for diaphragm valves to facilitate replacement
Tubes are generally connected using threads
For valves with small pipe diameters, threaded connections are generally used at lower pressures； Welding is used when the pressure is high. For toxic and harmful media, welding is usually employed ； For general media, threaded connections are used. For valves that require frequent maintenance and replacement of internal components, threaded connections are usually used ； For media that are relatively clean, free from corrosion, erosion, abration, etc., welding is used. :lol
Pipeline valves with a wall thickness of less than 1 mm can be connected using threads, but the external threads on the pipeline must have thread fittings welded to them in advance; they cannot be formed on-site.
Personally, I think that if a tube with a wall thickness of around 1 mm is threaded, essentially the entire wall thickness is removed. If the medium is corrosive, the tube is prone to breaking and leaking, and it’s also difficult to ensure its strength. It is still recommended to use clamps; if the pressure is high, welding is the only option.
For higher requirements, welding can be used; quick-connect clamps are also an option
Small, sanitary-grade pipes can also be welded; these pipes have a diameter of only 1 MM and are typically subject to low pressures. SWITCH LOCK connectors can be used for this purpose, but in the pharmaceutical industry it is generally required that the dead volume at the pipe joints be as small as possible, and SWITCH LOCK connectors result in a relatively large dead volume. Tungsten inert gas welding without solder can be employed to ensure that the inner surface remains smooth and even. Of course, the welder must have high skill levels, and they need to pass relevant assessments before being allowed to carry out welding. After welding, it may be necessary to inspect the inner surface visually if possible.