Tray-Carrier Proofer
1. Structure
The proofers are made of stainless steel pipes. To make cleaning and maintenance operations easier all the proofers are provided with internal side corridors, from below and atop, with access doors on both sides.
The conditioning unit is located on a platform, which is accessible by means of a stairway.
The proofer insolation panels stand on the ground or, in case of “L” proofer, on the elevated platform.
The same type of proofer can have different shapes, basically they are:
- Elevated L shape: this allows to make free floor space under the proofer in order to accommodate the oven or other equipment, it is mostly used, the only limit is the ceiling height.
- Elevated T shape: this allows to distribute the elevated parts on both sides from the proofer floor base; it is used when there is no possibility to adopt the “L” version; the only limit is the ceiling height.
- Box shape: classical box shape, usually provided with a cross-tunnel for lateral crossing.
2. Product conveying system
Includes:
The chain driving system which consists of a gear box under frequency inverter connected to a driving shaft with wheels which transmits the movement to the 2 sections of the chain on both sides of the proofer and at the same time. In case of big proofers the driving system can be split.
The chain, that gets motion from the driving system and moves the trays in the proofer. The chain is provided with bearings in correspondence with the trays connection pins. Oil free chains can be used to avoid contaminations: this has drastically improved the hygiene conditions inside the proofer. In the horizontal sections the chain runs on a PE guide.
The wheels around which the chain runs: they can be made of hardened steel or PE. The plate on which they are fixed is adjustable in order to center two chain’s sections. The wheels do not need lubrication.
The chain tensioning plates: these are activated by pneumatic cylinders when the proofer is switched on; when the proofer is switched off, the pressure of the cylinders is released to take off the tension from of the chain. This results in a longer life time of the chain and system control. The correct tensioning is guaranteed by sensors, positioned on the cylinder’s rod: they detect when the chain has to be stretched.
3. Product conveying support
The type of product conveying support consists of a tray carrier (rake type) with 2 or 3 levels.
Different designs of the tray carrier allow to accommodate boards, pans, tins.
The stainless steel tray carrier is fixed on both sides to the chain by means of pins in correspondence with the chain bearings: these pins can be easily removed to take off the tray.
4. Air conditioning, air distribution and insulation
Alitech supplies the conditioning unit with the air conveying and return system (ducting), designed to meet the requirements of the final product technology.
The conditioning unit is controlled by a PLC with indication of the set and actual parameters. Air distribution sleeves made of antibacterial inflatable fabric are used inside the proofer, they can be easily removed and washed.
The insulation of the proofer is made of sandwich type panels with both sides in stainless steel; the panels are self-carrying and arrive to the ground being slightly separated from the proofer frame to avoid dirt accumulation.
5. Maintenance, accessibility, hygiene
Although the different proofer types have different specifications what they have in common is the possibility of easy access to all the points inside the proofer that need maintenance or control.
The proofers are fitted with side corridors between the external panels and the frame, the corridors are under bottom and at the top part of the proofer, they are lighted by neon lamps and are served by access doors.
The product carriers that travel inside the proofer are also accessible and are kept high from the floor to facilitate cleaning operations. In case of chains with oil, the lubrication can be scheduled by means of a distribution pump. The bearings of the toothed wheels are lubrication-free.
6. Control
The operating system is designed like a graphic representation of the proofer with set-points, alarms and status of the different parameters. The information on the panel available to the operator and to the plant management is scalable to provide, for example, scheduled maintenance tables, productivity and energetic efficiency diagrams and coefficients.
Our aim is to present to the supervisor all the main parameters to manage and control the line at the same time reducing as much as possible the human presence on the machine side.