WIKA (Germany) - Pressure switches in food silos make a significant contribution to detecting overpressure in good time and safely preventing it. A manufacturer of such elevated vessels uses the model MA mechanical pressure switch for this task. One special property tipped the scales towards this explosion-proof instrument – it is also approved for dust applications.

In addition to the overpressure, there is also a risk of explosion due to dust formation:

The customer’s food silos accommodate bulk goods, primarily powdered milk, flour and sugar. Overpressure can build up during pneumatic filling, which endangers the safety of the silo and thus people and the environment. The presence of highly flammable dust can add to the risk of explosion. The risk potential is therefore large and requires appropriate measures.

WIKA’s customer has therefore installed a complex safety system to protect against overpressure in its food silos. The model MA pressure switch takes on a central function: It monitors the pressure profile in the silos and activates a valve when the defined limit value is exceeded, which releases any overpressure.

Robust pressure switch for safety-critical applications such as in food silos:

The model MA pressure switch is virtually predestined for safety-critical applications such as in food silos. As a mechanical instrument, it works without auxiliary power. It is fitted with either one or two microswitches that are actuated via a explosionproof joint.

The customer also selected the switch for its robustness. The casing consists of an aluminium alloy and can withstand pressures of up to 600 bar. The model MA has an IECEx or ATEX approval and is designed in accordance with the Ex d ignition protection type (flameproof enclosure). It can be used in both gas and dust environments. The switch is also available in SIL 2 and SIL 3 versions.

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The model MA pressure switch is also suitable for use in dust environments such as in food silos.