Scale-Tron's engineering team has the experience to handle custom systems in weighing, automation, scales, force measurement and many related applications.

Expertise includes load cells, scales, industrial controls, computer and PLC programming, computer system set-up, electrical and electronic circuit design, motor power circuit design, including variable speed AC drives, load cell mounting, travelling hopper design, explosion-proof systems, bag and box filling, loss in weight feeders, Autocad drafting, technical writing and production documentation.

Unique project examples 

Powder batching system.

A unique powder batching system was designed for Rehau Industries’ Baie D’Urfe, QC plant.  The objective was to weigh up to 7 materials, with weights varying between 50g to 4 kg, into plastic bags and seal them. The soluble bags are then hand-added to plastic materials in a mixer, creating specific blends for different jobs.

The batches had to be completed within 120 seconds at most, with an accuracy of ±0.5% of each ingredient weight.  These two conditions made it essential to use three separate weigh hoppers, discharging through a chute into the plastic bag which is held by a pneumatic clamp.  Ingredients are stored in bins standing on seven vibratory screw feeders, supplied by Vibra Screw Corp.  This type of feeder guarantees consistent feed of powders, some of which tend to clump and bridge.  The feeder discharge tubes are closed positively at the end of feed by sealing pads on spring-return cylinders.

The three hopper scales, shown in the picture, have capacities of 300g, 1500g and 4000g, are mounted on a single load cell each and have removable hoppers.  Discharge is activated from outside the hopper with a unique mechanism that only contacts the hopper during discharge, eliminating the forces and subsequent errors created by pneumatic tubing.

The system was controlled by our BatchTron-II controller, which handles both the speed and accuracy with ease.  Innovations were too numerous to list here, but we can discuss them with you.

Our wide experience in load cells, coupled with integrated mechanical and electrical design skills, give the ability to design load cell-based systems from scratch and guarantee their performance in advance.

Travelling weigh lorry, Thailand.

Bayer Premier Co. needed an automatic weighing system for their new plant near Bangkok.

The stainless steel weigh hopper had to be capable of withstanding an internal explosion without rupture and was to travel between 12 overhead hoppers, gathering materials, and four mixers where it would discharge the completed batches. Extendable seals were to make contact with hoppers and mixers before transfer of material, to contain dust. The hopper, mounted on load cells on a wheeled trolley and weighing over 10,000kg when loaded, had to travel on rails, powered by a variable speed AC motor. Weight data with an accuracy of 0.05% had to be transmitted over a festooned cable 200 ft in length to the controlling PLC. 

The whole was to meet Class 3, Division 2, Group G requirements for hazardous areas.

The system was delivered on time and was started up without requiring our presence on site. It has been operating successfully for five years.

We specialize in all sizes of job, big or small, in any location.

Scale platforms, Optimal Robotics Inc., Montreal.

A critical part of Optimal's automatic checkout counters for supermarkets (trade name U-SCAN), a load cell weigh platform checks the weight of every item dropped into the shopping bag after it is scanned by a bar code reader.  The item weight is verified by the computer without the customer even being aware of it;  if a cheap item is scanned and then an expensive item is dropped in the bag in its place, the operator is warned instantly.

Optimal's U-SCAN has been chosen by Kroger, A&P, Wal Mart, Costco, Price Chopper and many other leading U.S. chains.

Optimal's later U-SCAN model uses a rotating carousel scale holding 6 bag carriers (shown above) as well as a smaller single bag platform (shown on left), both of which are connected to the computer via load cell transmitters with serial communication.  These O.E.M. scales were custom designed to have 1 part in 15,000 resolution, allowing very small items to be weighed accurately on scales having capacities of 150 and 300 lb.  A major feature of these platforms is their rugged design, which withstands people sitting on their edges as well as heavy objects being dropped on them.

O.E.M. platforms with digital interfaces can be produced in any size and capacity with fast design turnaround times.

Carousel control system, Tunneling Systems Inc., Ontario.

A production "carousel" for moulding concrete sections for a Toronto subway tunnel required a control system.

The carousel system comprised a production line where moulds were to be sequenced through 12 separate stations, shunted via a transfer car to one of two alternate curing kilns, shunted through the kilns and out to another transfer car where they would be returned to the production line again.

Batching of concrete for seven different sizes of mould was also controlled by this system. Since the production line was crowded with unskilled workers, the potential for accidents was high and a special ultrasonic/microwave motion detection system was incorporated to prevent movement of the line when personnel were present.

The control system, operated from a graphic touch screen and PLC, ran fully automatically without a breakdown for the 2 year production cycle. This was the second such automation system designed and installed by Scale-Tron, the first being at Concrete Systems Inc's tunnel plant in Hudson, NH which produced a 9 mile 25 ft. diameter tunnel for the Boston Harbour sewage outfall project. 

This project (which did not involve load cells or weighing) demonstrates our knowledge of the precast concrete industry and its unique challenges.  We have the capability to handle both concrete batching and the more intricate controls that are required in highly automated plants.  Other examples include pick and place, travelling hoppers and automation of casting machines.        Tunnel Liner Plant Controls

Statistical Weight Control System, Blue Water Seafoods, Montreal. Blue Water's owner, Gorton's of Gloucester, MA was looking for a state-of-the-art system for gathering weight data from a number of load cell scales throughout the plant, calculating statistical data and presenting it in graphical form on colour monitors in the plant, for guidance of production personnel. We proposed a novel display format which would present the data in an easy to understand way along with a computer and data gathering system which could handle data simultaneously from many manual and automatic check weighing scales while displaying and printing several types of management tables and graphs. The system was installed in 1989 and originally ran on the PC-MOS multi-tasking operating system which was networked to three other computers. It has since been upgraded to Windows 95 and modified to run at much higher speed. The scales have a capacity of 2000 g at an accuracy of 1 g and the plant operator stations, including colour monitors, withstand a daily washdown with high pressure water. 

We have many years experience in the food industry, from automatic batching systems to platform scales, tank weighing and weight related process controls.  Customers include Kraft General Foods, Canada Packers, Fleischmann's Yeast, Best Foods and Portland Brewery.  We can offer guaranteed solutions to many problems.

Cable parameters testing station, Teleflex, Limerick, PA. Teleflex was looking for a method of testing the control cables used in power boats. Similar to bicycle brake cables, these cables have to operate in both tension and compression, and can be up to 60 ft. in length. The custom designed computer controlled machine would have to push and pull the cable while exerting an opposite force at the load end. Friction forces and the amount of compression or elongation were to be measured and compared with go/nogo limits of acceptance. A database of cable types would store the test speed, stroke, accept parameters and other data.

A test frame was constructed, housing a stepper motor controlled driver and pneumatic cylinder controlled load, both with position transducers, load cells to measure force and feedback from the load force to control the pneumatic cylinder. Custom clamps were designed to allow quick insertion of cables for production testing. The whole rig is 20 ft long and can extend to 40 ft for the longest cables (cables are looped to reduce the total length). Custom software was written in QuickBASIC and run under DOS, using commercial data acquisition and control boards.  

The system was completed in 1994 and has been highly successful in operation. It is still in daily use by unskilled operators.

This is an example of a highly custom system with very unique requirements.  It was built from scratch with very few changes and met stringent specifications. This ability allows us to tackle unique projects with a high possibility of complete success within a budget and time frame.

Special expertise includes load cell application. There are few if any load cell applications which we have not undertaken over the past 30+ years. From the smallest, milligram sensitivity to the largest, half million pound capacity, we have designed load cell based weighing systems for applications ranging from gold and silver to mining and hazardous waste. Call or Email for application information.

Safety of personnel and protection of plant equipment is our primary concern when engineering a new system. We ensure that our designs meet OSHA and other national and local standards for safety, as well as plain common sense. In the past we have refused to produce equipment as requested by customers when we judged it as potentially unsafe; instead, we have recommended design changes to remove the hazard. The Carousel system above is an example.

Cost effectiveness and reliability are our next concern. Our practical experience includes a vast knowledge of shop practices in a great many industries, from food, drugs and alcohol to chemicals, steel and aluminum mills. We know the special conditions in which equipment must operate and survive. As a result, we can build equipment which is suitable for the environment and which will work from the day of installation for many years until it is retired, to be replaced with a new generation of equipment. Often, we have been the supplier of the new generation, replacing our own original equipment after 15 or 20 years of use.

Product Index        

Our sister company, RL Scales Inc. specializes in engineering and manufacturing of O.E.M. scales and weighing systems.

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