Control panels help ready meals producers minimise production downtime

The control panels were built and installed by Peterborough-based systems integrator MLH Services, a customer of Block UK for more than 10 years. The first control panel was installed at Headland Foods’ production plant in Flint, North Wales, in order to control the spiral freezer process and associated cooling fans.

Established in 1990, Headland Foods Ltd is a leading manufacturer of frozen ‘own-label’ ready meals, supplying the UK’s major retailers. Now part of the Prize Food Group, which also comprises Cheviot Foods, Headland Foods produces more than two million meals each week across two manufacturing sites: Flint in North Wales and Grimsby in North East Lincolnshire.

The company employs around 1,000 staff and produces more than 180 different product lines across the traditional, Italian, Indian, international and health food sectors of the frozen ready meal market. A recent £15 million investment in its new Grimsby site, makes Headland Foods the first UK-based food company to install the latest fully automated lasagne line.

The Headland Foods plant at Flint uses an innovative spiral freezer system, custom-designed and installed by KE Parafreeze (formerly KE Jackstone), a Norwich-based company that specialises in the design and manufacture of industrial freezers.

David Everington, Director of KE Parafreeze comments: “The function of the spiral freezer system at Headland Foods is to freeze a high throughput of ready meals that pass through the plant, before they are shipped off to customers. The spiral freezer is fed by a conveyor system. The ready meals move slowly around the spiral-shaped freezer system, for around 45 minutes in total, after which they are sufficiently frozen to be ready to be shipped to customers. As a company, we designed and manufactured the freezer system, but for the associated electrical control panels, we used MLH Services, a local company with considerable expertise in small OEM and industrial automation systems.”

The novel design of the spiral freezer minimises the production space required in the factory and also ensures that the plant can meet high production volumes. The system is therefore critical to Headland Foods’ production process and so downtime must be kept to a minimum.

Back in 2002, after installing the spiral freezer system, associated cooling fans and control panel, there were some initial teething problems. Fan overload switches tripped occasionally causing production downtime. The 12 cooling fans that blow cold air through the spiral freezer were controlled by a single inverter drive via 12 separate thermal overloads. After consultation with Block UK, MLH Services concluded that the overloads were being tripped by reflective wave transience due to a long total cable length from the inverter to the 12 cooling fans.

In order to prevent tripping, Block UK recommended adding a motor reactor (choke) that would smooth out the PWM (pulse width modulated) waveform, closer to a sinusoidal waveform, thus improving the power quality. Mark Langfield-Holland, Partner at MLH Services comments: “With help from Block UK, we were able to quickly select and source an appropriate motor choke, which we duly installed in the control panel. This helped smooth out these irregular waveforms. Since installing the motor choke, there have been no further problems with the fan overloads.”

After the successful installation at Flint, KE Parafreeze and MLH Services have completed a similar system for Cascade Marine, a producer of ready meals based in Dubai. This time, the panel was skid-mounted so that the customer could install the system as a complete freezer unit. Another identical control panel for a second spiral freezer system is also currently being installed at Cascade Marine. Again, Block UK supplied the three-phase power supplies, EMC filters and motor chokes for the control panels.

Set up 12 years ago, MLH Services is a systems integrator and provides a complete range of services to companies involved in industrial automation and process engineering. MLH Services offers expertise in PLC, inverters, HMIs, transformers and industrial controls. MLH is also a distributor of Meiden drives.

Block UK has been MLH Services’ preferred supplier of electrical products for more than 10 years. Components sourced from Block include motor reactors, transformers, power supplies and EMC filters. Mark Langfield-Holland comments: “Generally, the standard is superior with Block products. The reliability and the quality of build of Block’s products are very high, as well as speed of supply, particularly for custom-designed systems. Many of my customers are small OEMs and so each application presents its own unique problems. Technical support is therefore key and over the years, this has been excellent from Block.”

For more information on Block UK’s range of power supplies, motor reactors and EMC filters, please visit www.blockuk.co.uk or telephone the sales department on 01621 850 666.