New ATEX Silo Protection

Hycontrol is No.1 when it comes to silo protection systems. Our system is the only system to meet current MPA guidelines and it doesn't just stop there! Hycontrol are now offering an ATEX option for the silo protection system!


Many industries such as food, pharmaceutical and quarry, handle and transport millions of tonnes of product every year.  This product comes in many different shapes, sizes and densities, but a great deal is shipped in powder and particulate form. These products are shipped from site to site, mainly by road tanker, and are then discharged from the tanker to the site's silos by fluidising the powder and blowing it into the silo.


This pneumatic conveying operation uses air to carry the product into the silo and this air must then be vented via a suitable filter.  Silo protection is necessary as there are inherent risks with delivering product in this way:-


1)  Over-pressurisation.   If the air is not vented then the silo can become pressurised and most silos are not tested as pressure vessels.  Indeed, only a small increase (such as 1 psi) may be sufficient to either rupture the silo or blow the filter element off the silo roof.

2)  Over-filling.  Another common problem is over-filling the silo as a result of a level probe failure or wrongly specified technology for the application.

Both of these conditions necessitate the need for a silo protection system.



The pressure relief valve is the silo’s last form of defense against over pressure. This unit is normally fitted to the roof of the silo and prevents either an over pressure or negative pressure in the silo since both of these may cause severe damage.

This valve is available in a number of different materials and has a wide range of up-stand adapters to simplify retrofitting to existing silos. These units can be fitted with the ground level test module for a complete test of operation before each delivery to test if the valve is operational.

A PRV should never be operated if the correct silo protection system is fitted as the inlet valve will close should an over -pressure condition occur however they will protect the silo if the pressure exceeds 50mb or 0.75psi. 


FLEX 500:-

This sensor monitors the pressure in the silo and transmits it to the control panel where control actions and alarm signals can be initiated. 

Typically a pressure increase signal would be used to close the discharge valve in the fill pipe to stop the tanker over-pressurising the silo.

The FLEX-500  is an advance on other sensors currently in use.  It is the only one that can carry out the following test functions which are essential for a silo protection system:-

All of the above are carried out with the simple press of a button at ground level before a delivery takes place. This ensures that the primary element is working correctly and it is safe to unload the tanker providing the other silo protection components pass their tests!



Vibrating probes are the most effective high level probe to use on solids and powders for many reasons. This technology is unaffected by changes in temperature, pressure and humidity and is unaffected by material changes such as dielectric.
They require no calibration and the design has a self cleaning effect.

Many vibration twin fork designs suffer from bridging where product gets jammed in between the forks causing false alarms but the unique single Diamond blade is immune to this. The Diamond point range has one vibrating knife blade with another inside. This provides excellent sensitivity for light materials but also an extremely strong blade for vertical loading.


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