Food – Oven Upgrade – Burtons Biscuits, Edinburgh – 2022

Line 1 Oven Upgrade

The Project:

Burtons Biscuits tasked UCS Automation with an oven upgrade as the existing system was no longer gas safe compliant. The existing system had one hundred and eleven burners, with limited gas safety. The new system included a dedicated Kromschroder FCU500 gas safety controller and and an ESA Estro Q2 flame supervision unit for each burner.

Surveying the Project:

We spent a lot of time understanding the operation of this oven before we started any design work, the details are in Understanding the Process.

We had a couple of concerns following the survey, so needed to address them for a successful project

• Could the number of flame supervision unit be controlled simultaneously?
• Would our normal cabling arrangements be suitable for the application?
• Could we accurately control the oven’s temperature and pressure curves?

We spent a lot of time in the research stage, establishing the best methods to answer these concerns. The amount of wiring that would have been required to operate this would have exceeded the available space on site. This result in the implemenation of a Schneider Electric power and communication bus bar system being implemented.

We decided to utilise a similar software arrangement, previously used with our heavy clay customer, for the oven control. Oven and kiln controls are very similar, with the biggest difference being the temperatures they operate at. Utilising this meant that the temperature and pressure control wouldn’t need to be started from scratch resulting in a much faster developement time for the control software.

The Existing System

Design

Our project engineer began work on the new control system, starting with the general arrangement and electrical layouts. These were checked with our site findings and when we were happy, issued the build order to our in-house workshop. Whilst the control panel was being assembled, our project engineer was working on the software development. Due to the size, the wiring for the ESA units was completed first, meaning each of the 111 units could then be programmed and tested individually to verify operation.

The Control System

The client used Rockwell Automation’s Allen Bradley line of PLCs as standard, so our solution needed to use it too. We decided to use a GuardLogix PLC, ArmorBlock remote I/O, PanelView Plus 7 HMI, Kinetix 5500 servo drives and Powerflex 525 inverters. We used the ethernet protocol to issue commands and monitor the safety and alarms, allowing us to minimising the wiring requirements. The PanelView Plus 7 HMI was a 10.4” colour screen, allowing the operator to control the active elements of the process, monitor the machine status and adjust operation parameters. It also provided detailed warning and fault information that was useful during commisisoning, but allows the operators and maintenance teams to address issues quickly in production.

Construction, Installation & Commissioning

So we could debug the control panel and software, it was put under test in the workshop before the site installation. The aim was to minimise the commissioning time on site. With only a small window for production shutdown we had to deal with all forseeable issues in advance.

During April 2021, our electricians removed the existing motor,  mechanical linkages and cam profilers. They installed the new panel onsite, along with the new servo motor system, wiring and mechanical adaptors, inlcuding new drive shafts. Our project engineer arrived on site at the end of the installation and began commissioning the day of the completed install.

Discussions with the machine operators and engineering team throughout the process enabled the project engineer to commission the system quickly. The timings and positioning that we couldn’t do in advance were sorted and a couple of modifications were added to improve the machine.

Overall the client was very happy with the delivery, and has requested a similar upgrade to five of the other ovens on site.

Our Services

We provided the following services for this project:

• Electrical AutoCAD design drawings. See our Design page
• Control Panel Manufacturer. See our Manufacture page
• PLC & HMI Software design. See our Software Design page
• Operation manual
• Risk Assessments and Method Statements for the installation
• Disconnection and removal of the control system
• Installation, Testing and Commissioning of the system. See our Installation and Commissioning pages

Capping Machine Upgrade photos

Understanding the Process:

We needed to learn and understand the operation of the capping machine to upgrade the control panel and software required to operate it, so we divided the process several, smaller functions.

A) Mechanical:

The existing mechanical system used chains and cams and was operated from a single motor. There were nine rotation points on the machine, meaning we needed this many servo motors on the new design. We also needed to consider the mechanical work to install and mount the new motors. We also needed to log the cam profile before we continued any further work.

B) Shuffleboard:

The shuffleboard recieves row of lids and bases and adjusts the order to produce columns of alternating lids and bases. The capping process needs this to work correctly. We had to consider the start and stopping times for the shuffleboardas the inertia of it prevented immediate start stop action. The jam and capper timing needed linking to this process. Too fast would result in too many biscuits in the holding area but too slow would cause shortages.

C) Holding area:

Immediately following the shuffleboard is the holding area, it is a conveyor belt with guide rails to align the lid and base columns. It also needed to hold enough product to keep a consistent product flow. There are also a set of sensor in this area, checking for the order of biscuits in the zone. The software monitors for lid holes and solid bases and flags an operator if the ordering is incorrect, allowing the operator to correct the issue and prevent the line from losing synchronization.

D) Rotodex Rough Spacer:

The rotodex rough spacer is a rotary axis with pins on and rotates at the end of the holding area. It processes single biscuits giving a rough space for capping alignment, but if it is too fast or slow and the biscuits will only pass partway through, breaking the biscuit. This causes both lost product and time to rectify. This feeds onto the capper conveyor.

E) Capper conveyor and rotodex fine spacer:

The capper conveyor moves the bicuits down through the rotodex fine spacer, jam depositer and capper. We needed to consider the speed because if it is incorrect it will cause misalignment, resulting in lost product. This rotodex is roughly the same as the rough spacer, but pin spacing is much closer and retards the biscuits to get precise alignment for the jam depositer. As with the rotodex rough spacer this is speed critial, deviations would result in broken biscuits, missed jam deposits and poorly aligned lids.

F) Jam depositor:

The jam depositer uses a cam profile to add jam to the base biscuits and moves in both the horizontal and vertical plains. Firstly it moves towards the fine spacer and then lowers down in line with the base biscuit. The depositor then follows the base biscuit and the jam pump is activated, placing jam on the base. As the depositor approaches the end of the horizontal movement it quickly moves upwards to break the tension. The high speed prevents the base biscuit from moving. If it moves too slowly, the biscuit will move out of position and result in poor alignment for the capper, meaning waste product. This process is completely timed with no sensors to detect any issues. The jam depositor also operates via timing with an inverter driven pump, triggering needs to be accurate.

G) Capper:

This is similar to the jam depositor but only uses a vertical axis. It aligns with the biscuit lids then pneumatically picks them up and holds them in place. Once the jam filled base biscuit is underneath the lid is lowered onto the jam and released. There are a set of forks to align the biscuits, but no sensors.  The air pump also had to be timed correctly to prevent misplaced biscuits.