Author Archives: zollt

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For the 2018 onion harvest Bennett and Co completed a 1700tonne onion store for J S Means (Terrington) Ltd.  The building is situated on the edge of their existing farm yard and had to be carefully sited to allow for adequate apron space in front of the building for grading, loading and unloading.  A high tension cable close to the proposed building was buried in a duct and a ditch piped to enable the structure to fit in the site and not compromise the irrigation reservoir behind the building or the client’s existing concrete standing for empty potato boxes.

Due to the nature of the marsh soil conditions and a redundant back filled pond on the site, the foundations were piled before a large reinforced base slab was constructed on top of the piles.  Once this was achieved the steelwork could be erected.

The drying floor is a hardwood deep bearer timber floor supplied and constructed by Flach and Leroy, designed specifically for this type of application with the large airflows needed in the first stage of onion drying.  The floor is constructed from a double bearer and the stability of the bearers is maintained by lateral struts along the length of the floor giving an overall height of over half a metre.  Inside the main air duct there are air inlet doors with stepped wooden blocks allowing the doors to be partially opened to enable further control and flexibility in airflows used.

The timber necessitated a large reinforced concrete up stand around it.  This in turn required two bridges constructed over the up stands to access the building to install the concrete panels for the outside walls, sides and roof of the central main air duct and then the installation of the timber floor.  Once this was completed the bridges were removed.

Fläkt Woods supplied three 1400mm diameter fans with guide vanes and large silencers.  These are controlled by inverters to keep the starting loads to a minimum but also to enable the airflows in the store to be closely controlled by air speed sensors in the crop and an air duct pressure sensor.  This is achieved by the Vegtec controller which also controls the air mixing louvres and brings in the refrigeration when required for pull down and maintenance of crop temperatures during storage.  The controller can be remotely accessed by GSM modem to a mobile phone or computer.

Heat for drying is from a Harvest Installations modulating gas burner that can be modulated for either temperature or relative humidity (used if drying grain).  This controls the drying air temperature and with the use of the Farm Electronics motorised louvres the relative humidity of the air is controlled too during the drying phases.  The louvres are also used to provide ambient air cooling and recirculation to bring down and maintain crop storage temperatures along with the refrigeration unit.

The Farm Electronics refrigeration unit has a large evaporator coil installed into a divider wall in the fan house with its own recirculation louvre to draw air off the top of the crop and into the plenum created behind the divider wall and sucked through the coil by the bottom fan.  The compressors and condenser coil are put together in a factory constructed box unit with the condensers on the roof.  This is mounted outside the fan house.

With the need to keep onions near to 0-1ºC the building cladding is insulated composite sheet with plastisol coating, with the insulation 100mm thick giving a U value of 0.2W/m²/ºC.  The costs of running refrigeration are such that insulation of this level is economic.  To improve the insulation properties of the building further the client chose to have a door with 80mm thick insulation panels.

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Before Construction

Bennett and Co have completed for harvest 2018 a major investment in grain storage for Buckminster Farms Ltd.  Following a complete review of their grain storage facilities and requirements, Perry of Oakley and Bennett and Co were asked to

provide a solution.

The design required two storage areas of 2500tonnes each with sufficient intake and drying capacity.  Perry supplied the 60tph continuous flow drier from their new Savannah range complete with their light grain and chaff recovery system, invertor speed controlled main fans and touch screen control.  They also supplied 120tph bulk handling equipment including intake trench conveyors, aspirator cleaners, elevators, a variety of chain and flight conveyors and a belt conveyor to load the storage areas.

After Construction

The building has been cut into a slope, which reduces the impact of the building in the landscape and also allows for a large intake pit within a 350tonne bunker area of the building with two trench intake conveyors.  Grain in the two storage areas is stored to 6m at the wall side peaking to 10m under the belt conveyor.  The below floor cooling ducts are arranged so as the building is loaded/unloaded crop can be still ventilated.

The drier, plant and grain cooling fans can all be monitored and controlled remotely thanks to the estate’s own super-fast broadband network with a mast on top of the new building.

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As we are ending another mild winter, store ventilation and control may well have proved problematic.  It is also worth a reminder that the new CIPC regulations come into effect in July this year and there is still time to contact Bennett & Co for advice about ventilation and upgrades for existing stores.

 

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For any new storage projects, Bennett & Co suggest that you visit the new project planning pages on their website which lists a range of things which need to be considered.  For example, if the proposed site is likely to be on fenland, which traditionally has a low soil bearing capacity, Mike, working with experienced structural engineers, can provide solutions for all your land needs such as piling, drainage, watercourses and ponds.  Working with specialist groundwork subcontractors allows the foundations and bases to be well prepared prior to erection of the storage facilities.

Mike is also experienced in submitting complex planning applications and liaising with the relevant planning authority.  This may well include environmental considerations, such as surveys to minimise impact on wildlife and landscaping the site as well as noise surveys and any potential effect on the local area.

For all your storage needs both new and existing, Bennett and Co can offer a complete turnkey solution.

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The summer of 2010 saw the commencement of work on a new 4500tonne store for Waldersey Farms Ltd.  Their brief was to build a store accommodating three storage areas – one for drying and storage of onions, one for grain drying and one for dry grain storage.  This would provide improved storage capacity and, in a part of their landholding without adequate crop storage, would allow both onion and grain drying.  It was to be sited in an existing farmyard and included demolishing existing buildings and recycling the material, as well as backfilling the existing tanks and pits of the former pig unit.  Despite its remote location, particular care needed to be taken with regard to noise levels, as well as a concern about bats in the buildings to be demolished.

Bennett & Co were appointed as Principal Designer and Principal Contractor, with the remit to design, implement and manage the entire project.  Being fenland, the stability of the ground was an issue and working closely over the design with consulting engineers, Plandescil Ltd, 198 piles were constructed by the specialist contractor Keller using VCC type piles (Vibro Concrete Columns).  The extensive reinforced concrete slab required was completed by D G Scales Ltd prior to erection of the steel-frame building by A C Bacon Ltd.  A hardwood timber floor was fitted in all storage areas by Challow Ltd.

Harvest Installations fitted stirrers and a CHC modulating gas burner in the grain drying store, with a further CHC in the onion drying store.  Automatic louvres and a central control panel were installed by Farm Electronics Ltd and the complete store was ready for harvest 2011.

Farm buildings prior to project development from Bennett Crop Storage
Existing farmyard before upgrading the store
Cambridgeshire onion and grain store
Following completion of project
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Following Stody Estate’s initial enquiry about improving their grain storage capacity, Mike Bennett of Bennett & Co worked closely with them ensuring their brief was fulfilled.  Using a Bacon building and a Challow hardwood drying floor, the 2000tonne store was erected and a Harvest Installations Maxi stirrer system installed.  Stirring to aid bulk drying of grain is now a standard means of enabling faster and more efficient drying in on-floor stores to greater storage depths – 4m depth in this particular case.  Mike has over 25 years’ experience with Harvest stirrers and is happy to discuss the benefits and suitability for the individual client.

second-stody-picture-2016He also installed a Constant Humidity Controller, an allied Harvest Installations product, which enables continuous grain drying, 24 hours a day.  This has significant benefits and enables the grain to be dried faster without the need to depend on external conditions.

If, however, as in the case of Stody Estate, the noise levels needed particular consideration, Mike fitted acoustic inlet louvres which significantly reduce any noise impact on the surrounding area.

Bennett and Co undertake a variety of work involving potato, onion and vegetable storage, as well as drying of other products.

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In the autumn of 2014 Bennett & Co completed a 4000tonne refrigerated potato box store for Patrick Dean Ltd.  The brief was to build a store with four storage areas within the existing farmyard as part of their significant potato growing enterprise.  The design needed to incorporate storage for both ware and seed crops in separate areas, with a covered loading and unloading area.  (CIPC is not used therefore it is acceptable to have both seed and ware crop in the same building). The large roof area was also needed to provide additional PV panel capacity to augment the new large electricity supply to the site.

Working with Patrick Dean, a design was achieved to meet their requirements of fitting this large building into the existing farmyard.  Most of the designated area had previously been a pig unit but recently had been a storage area for potato boxes.  Old slurry channels and tanks needed to be dug out and refilled with backfill and then compacted to provide a firm foundation for the building and its concrete floor.

Due to unavoidable delays in getting the project underway, the floor was laid in a single day with laser screed machines and additives included in the concrete specification thereby allowing the cladders to move in and install the internal walls within 2-3 days.  The size of the building allowed the cladding, ventilation and doors to be fixed at one end of the building allowing the client to fill part of the store before the other end was completed.  This required carefully planned project management.

The refrigeration, ventilation and control equipment was supplied by Welvent, who have supplied the client such equipment over a number of years.  25kw packaged fridge units were installed in the seed stores and 90kw units in each of the ware stores.  The building was supplied by A C Bacon Engineering Ltd with ground work and concrete floor by local contractor K&S Allbones.

Bennett & Co designed the store, obtained the planning consent and project managed the construction.

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This project arose out of a client’s need to resite the farmyard away from the old buildings that have provided sites for new and alternative businesses and the need for improving returns from the expanding potato crop.  Therefore the brief was to ensure that the building would be sited to allow further expansion of the farmyard with additional buildings at a later date.  It also had to provide new workshops for the farm and a certain amount of machinery storage as well as two potato box storage areas which could be kept under different storage regimes if required, plus grading area.

The green field site presented a number of particular planning, drainage and groundwork problems which were successfully overcome by setting the building on an especially designed ring beam foundation.

rhf1The building, supplied by A C Bacon Engineering, was clad with insulated composite cladding over the roof and sides of the storage area including a dividing wall.  The stores were filled via eave height with insulated sectional slide-over doors.

Space at the rear of the store was at a premium because the building needed to be cut into a bank on the site boundary.  The choice of refrigeration units assisted greatly in this.  Two Welvent packaged refrigerated air mixing units were installed with the plant completely contained within the unit inside the building so removing the need for condenser units outside.
rhf3A new electrical supply was brought onto the site which meant that a plant room was constructed at the rear for the meter and distribution boards etc.

rhf2The Welvent units are controlled by their UAPC controller which provides precise control of the store environment utilising low tariff electricity which can be used with a printer or have the facility for remote sensing by PC.  The unit also has the ability to control the CO2 levels within the store.

 

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AM2This particular farmer has had three Harvest Installations Constant Humidity Controllers for a number of years.  These have operated on both indoor round bins and outdoor silos as well as a floor store used to dry grain prior to storing their main crop potatoes.  When the Maxi-stirrer was first developed it was recognised that this store lent itself to its use in speeding up the drying of relatively large batches of grain, but at the time the larger three double auger unit was not available.

The store has an underground main air duct with below floor lateral ducts.  This allows the stirrer tracks to be mounted off the building stanchions on both sides, so that the stirrer spans the whole building.  The client constructed the tracks and brackets himself.  The building is well ventilated with large vents down both sides.  This is important when drying with a stirrer at high temperatures as the exhaust air will be saturated.

Much lower quantities of air are required for stirrer drying than for conventional floor drying, consequently the inlet on the existing fan is baffled to reduce the volume of air produced.  The client’s Harvest Installations Constant Humidity Controllers are used all together to provide the heat required to raise the air temperature.  Two are operated at full output using “click-boxes” to act as dummy sensors with the third providing temperature control.

 

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all1A major potato producer in the Fens had a suite of specialist potato box stores, some with refrigeration.  However they had no specialist grain drying and storage facility.  They felt that silos provided a secure means of storage to provide good quality assurance.

Two 30ft. dia. Westeel silos were selected as the most economic solution.  Drying floors with Hutchinson Powersweep silo unloaders were included with drive for the sweep augers from the outside of the silos.  To provide rapid drying at depth both silos were fitted with Harvest Installations Maxi-stirrers.  This will allow batch drying to be done if additional storage silos are added at a later date.  A 15hp fan with 2 million BTU/hr Harvest Installations Constant Humidity Controller provides the high temperature low airflow regime required for the high rates of drying possible with stirrers.

legge1The site is situated on peat fenland where the soil is very unstable.  An especially designed transformation duct feeds the hot air into either silo.  This is because the silos needed to be some distance apart to spread the load and allow each silo to “float” independently. A large base area of hardcore was constructed on top of the clay subsoil before the especially reinforced bases were laid.

The silo is filled with a 200mm dia auger with a nominal rated capacity of 50 tph.  This is also used for outloading in combination with the Powersweeps.  This provides a low cost secure drying and storage facility.