Silo maintenance – when did you last check your silo pressure relief valve or filter system?

Do you have storage silos on site?
If so, when did you last check your systems?

Silo maintenance pic beforeImage No 1 – Silo maintenance – pressure release valve before maintenance

Image No 1. shows a silo roof that the Spirotech-SRD silo maintenance team recently checked. The silo had obviously not been looked at for many months. In this condition, should an overpressure or vacuum situation have occurred within the vessel, it is very likely that this valve would not have worked correctly – if at all. It is also evident from the surroundings that dust will have been emitted to the atmosphere causing a Health & Safety issue.

But what really is the importance of silo maintenance?

Structural damage to the silo could occur with the valve in this state. The main reason for the valve being in this condition was that the silo filter system had not been operating for some time, so the only other release for the displaced air from the tanker delivery would have been through the pressure relief valve.

Silo maintenance pic afterImage No 2 – Silo pressure release valve after maintenance

Image No 2. shows the valve fully stripped down and thoroughly cleaned. It can now clearly be seen that if needed this will operate as required. In addition, a full service and overhaul of the filter unit will allow the vessel to vent correctly through the filter and not through the pressure relief valve. If a Ground Level Testing System had been in place this valve would not have been able to get to this advanced stage of neglect as it would have been detected well in advance of this condition.

Improving safety and the environment

The most simple of silo maintenance tasks will improve the safety of site operators as well as protecting the vessel and its environment. Regular maintenance of silo filter systems, level monitoring and pressure relief valves will ensure a quicker and safer tanker delivery and can improve the overall performance of the vessel.

Forticrete – a company that’s doing it right

Following a recent service to the Forticrete plant at Anstone in South Yorkshire it was noted that the silo roof areas always seemed to suffer with material overfills and potential over pressurisation of the silos during tanker deliveries.

Spirotech silo maintenance engineers advised that the site would benefit from a silo safety system which would not only protect the vessels during the tanker deliveries but would also carry out ground level checks prior to the delivery to ensure that all the roof mounted equipment was in good working order. Spirotech had already installed similar systems on three other Forticrete sites, including a new silo incorporating Spirotech’s Ground Level Testing System and new weighing system on one of the sites. These have resulted in safer, cleaner and more environmentally friendly deliveries of products to the silos.

“Forticrete have now used the Spirotech silo maintenance service on a number of occasions for retro-fitting our cement silos with the latest silo monitoring technology at ground level. This has dramatically reduced the need to access the top of the cement silos and therefore improves the health and safety of the employees.  Spirotech also successfully installed a new 40 tonne cement silo at one of our sites and all associated work was carried out to a very high standard of quality and safety.”

Adrian Drysdale
Operations Process Manager
Forticrete Ltd.

Silo maintenance for Forticrete

Image No. 3 shows a new silo recently installed at the Forticrete site at Stretton. Designed by Spirotech’s design team and built at our 40,000 square feet factory in Cambridgeshire, the new silo is also fitted with the Spirotech Ground Level Testing System. The Ground Level Testing System (GLT System) was designed and developed by Spirotech to ensure that silos and the environment are kept safe at all times during tanker filling.

The system reduces the need for climbing to roof level to check operation of pressure relief valves, level probes and pressure monitors, and carries out pre-checks to the silo pressure relief valve and high level probe and pressure monitor prior to commencement of tanker discharge. Should any of the above be in an alarm state then the system will not allow the tanker filling to commence until the alarm is cleared. During the tanker discharge it will also monitor for high level or high pressure and if an alarm occurs, warning klaxon and lights will activate to advise the tanker operator to stop filling until the alarm is clear.

Forticrete’s existing silo had reached the end of its usable life and Forticrete approached Spirotech to design and build a new silo to provide additional storage but without any increase in the height of the existing unit. Spirotech’s team of installation engineers removed the old silo and installed the new vessel, along with its safety systems, during a factory shut down thus minimising any lost production from the plant.

Silo maintenance helps prolong and protect

It is quite often the case that the maintenance of a silo is something that can be an oversight on many sites. Site engineers are often kept busy just looking after production machinery and in many cases see the silo as a ‘non maintenance’ item. However the silo is a very important part of any production facility as it supplies the raw materials to enable the final product to be manufactured. If the silo is not regularly maintained then production could easily come to a halt.

Ground Level Testing SystemThe Spirotech-SRD Group Ltd Ground Level Testing System

Ensuring regular service and maintenance, along with installing a silo safety system, will prolong the life of the vessel and protect the operators and the environment in which they work. The recent installation of the Spirotech-SRD Group Ltd Ground Level Testing System, along with regular service work undertaken at the Forticrete Anstone site, will ensure that the production facility can rely on a good supply of raw materials from the silos at all times with no costly down time or lost production.

So how important is silo maintenance?

‘Very important’ is the answer.

Spirotech-SRD Group Ltd carry out silo servicing and maintenance on many sites throughout the country. Our team of engineers carry out pre-planned service visits covering items such as reverse jet filter systems, pressure relief valves and level probes, along with silo conveying systems including screw conveyors and pneumatic powder handling systems.

As part of Spirotech’s ongoing service we also offer advice on any potential improvements and repairs that we feel may be required to improve current systems and keep the plant operating at its optimum performance. If you would like more information about silo servicing, maintenance or our GLT System please call our sales team on +44 (0)1487 832 053 or by email to