Category
Overflow Switch for Screw/Chain Conveyors
Detect blockages and overfill on screw and chain conveyors before they cause damage.
A conveyor overflow switch is a membrane level switch fitted in a screw or chain conveyor casing that trips when material backs up at a blocked or overfed discharge, so you can stop the drive before it overloads. Filsa's switch handles dusty, powdery, granulated and grainy bulk goods and is rated to +0.5 bar.
1 Product · Overflow Switch for Screw/Chain Conveyor
Selection guide
Overflow Switch for Screw/Chain Conveyors Guide
How a conveyor overflow switch works
The switch mounts in the conveyor casing, typically near the discharge end. Material pressing against its membrane, once enough has built up, moves the membrane and trips an internal microswitch. There's nothing moving inside the casing to jam, so it keeps working where a mechanical paddle or float would foul on the screw or chain.
How to choose a conveyor overflow switch
- Mounting point: fit it in the casing near the discharge end, where material builds up first if the outlet blocks, or anywhere along the casing to catch overfeeding.
- Detection point: the same membrane switch works for either maximum level (overfill) or minimum level, depending on where you mount it.
- Material: the standard NBR membrane suits dusty, powdery, granulated and grainy bulk goods; stainless steel 1.4301 is available on request for abrasive materials.
- Protection: IP53 or IP40, depending on mounting position.
- Temperature and pressure: product temperature -25 to +80 °C, maximum vessel pressure +0.5 bar.
- Contact rating: a 1 NO + 1 NC contact, 15 A at 250 VAC for resistive loads, enough to stop the conveyor drive directly.
For blocked transfer chutes instead of conveyor casings, see the chute jam level switch. For high-level detection in a silo, see pendulum level switches.
FAQ
Common questions
Where should the overflow switch be mounted on a screw conveyor?
In the casing near the discharge end, where material builds up first if the outlet blocks or the conveyor is fed faster than it can carry. That position catches an overfeed condition before it works back up the full length of the casing and overloads the drive.
Can the switch detect minimum level as well as overfill?
Yes. It's the same membrane switch used for both, so which condition it detects depends on where you mount it on the casing rather than a different model. Tell us the level you need to catch, maximum, minimum or both, and we'll confirm the mounting.
Which materials can a conveyor overflow switch handle?
Dusty, powdery, granulated and grainy bulk goods, with a standard NBR membrane. A stainless steel 1.4301 membrane is available on request for abrasive materials that would wear NBR quickly. Tell us the material and we'll confirm the right version.
What is the difference between this switch and a chute jam switch?
Both use the same membrane switching principle and the same specifications, but the overflow switch is built for screw and chain conveyor casings, while the chute jam switch is meant for transfer chute walls. Choose based on where your equipment actually blocks.
What temperature and pressure rating does it have?
Product temperature -25 to +80 °C and a maximum casing pressure of +0.5 bar, which covers standard screw and chain conveyor duty. Tell us if your process runs outside that range and we'll check an alternative.
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