Flow path
A strainer housing is full when it is opened. Two small connections decide where the medium goes: the vent at the top, which breaks the vacuum, and the drain at the bottom, through which the contents flow out in a controlled way. Both are part of our standard equipment – how they are designed depends on the medium.
1/2″ socket in the cover
1/2″ socket in the bottom
independent of the nominal size
Flange instead of socket
Without a vent, a vacuum forms during draining – the medium drains only intermittently or not at all. Without a drain, the contents of the housing have to come out when the cover is opened. With water this is a nuisance; with hot, aggressive, flammable or expensive media it is a safety and cost problem.
That is why both sockets are standard with us, not accessories: 1/2 inch in the cover, 1/2 inch in the torispherical head – the same for every nominal size. What you decide is the design: closed with a plug, with a ball valve for quick draining, or as a flange if the medium is viscous or carries solids.
The first two items are standard equipment; you select the others as additions.
Breaks the vacuum during draining and lets the air escape during filling. It sits in the cover because that is where the air collects. Closed with a plug on delivery.
Sits in the torispherical head at the lowest point so that the housing drains completely. Also 1/2 inch – the size is determined not by the nominal size but by the task.
Instead of loosening the plug, a lever is turned. This saves time at every cleaning and prevents medium from escaping uncontrolled while unscrewing. It is one of the most common additions to a strainer.
Viscous media and settled dirt do not drain through a 1/2-inch socket. In that case a flange is welded in – it grows with the nominal size: on a DN200 strainer about DN40 for the drain, on DN400 around DN50.
The T-type strainer has no torispherical head in which the medium collects – here the vent is located in the housing cover, either as a socket or a flange. Draining is via the line.
You determine the connection position: with a flat bottom, also on the side instead of underneath. We retrofit drains and vents on screens, strainers and filters, including those from other manufacturers.
Standard equipment and variants by type. Other sizes and positions are possible.
| Type or feature | Design | Note |
|---|---|---|
| Standard equipment | ||
| Vent on basket, simplex and duplex strainers | 1/2" socket | in the cover |
| Drain on basket, simplex and duplex strainers | 1/2" socket | in the torispherical head |
| Pot type strainer | Socket G 1/2" | in cover and bottom |
| T-type strainer | Socket or flange | vent only, in the housing cover |
| Variants | ||
| Ball valve | on socket or flange | draining without tools |
| Drain flange | DN25 – DN50 | size increases with the nominal size |
| Vent flange | DN15 – DN25 | for large strainers and gases |
| Connection position | bottom or side | side with a flat bottom |
| Sealing plug | Standard | if no valve is fitted |
A closed socket costs nothing extra. But at every cleaning someone has to loosen the plug with a spanner while the medium is standing behind it. With a ball valve this becomes a single movement: bucket underneath, turn the lever, done. That is why we suggest it ourselves if you clean frequently.
Yes. Before production starts, you receive the design draft for approval – the drawing also shows the position and size of the vent and drain. Only once you have confirmed it does the order go into production.
Gladly. Drawings, specifications, parts lists or the data sheet of the previous strainer are the best basis. Our design engineers adopt your requirements and adapt them where manufacturing or the applicable code requires it – we agree any deviations with you in advance.
Yes, on basket strainers, simplex strainers, duplex strainers and pot type strainers both sockets are part of the standard equipment. On the T-type strainer, due to its design, there is only the vent in the cover.
Because its size depends on the task, not on the nominal size. Half an inch is enough to drain a housing in reasonable time – even a large one. Only when the medium is viscous or carries solids does the cross-section become a bottleneck; then a flange is used instead of the socket.
For viscous media, for slurries with a high solids content and whenever the housing has to be emptied quickly. The flange grows with the nominal size – on a DN400 strainer it is typically DN50.
Yes. With a flat bottom instead of a torispherical head, it is positioned on the side at the bottom. This happens when the overall height is limited or the strainer stands on a frame.
Yes, also on filters and strainers from other manufacturers. The housing is a pressure vessel – the work therefore includes welding, testing and documentation.
All topics at a glance: Strainer options
Tell us the medium, its viscosity and how often cleaning takes place – this determines whether a socket with valve is sufficient or a flange makes sense.
