The story behind Flexspeed

Flexspeed trebles the capacity on the same space as a traditional filling plant. It is an extremely simple system that increases the accuracy in filling, check-weighing, leak testing etc. and at the same time reduces maintenance to a minimum.

Mr. Bent Lindrup, Technical Director of The Kosan Crisplant Group, is excited when he tells about the unique features of Flexspeed:

“A colleague of mine is in the beverage business and knows the dynamic bottle feed systems.” explains Bent Lindrup. This became the source of inspiration for the system.

The goal for the team of developers was to fill 3,600 gas cylinders per hour. Defining the top level this high (the capacity at traditional filling plants is 1,200 cylinders per hour) it was imperative to think out of the box.  

Inspired by beverages

For the last 20 to 30 years the beverage industry has used the technology for conveying bottles, cans and casks. It is an efficient and well-tried technology and so Kosan Crisplant’s team of developers visited a few beverage companies in Denmark in their quest for an answer.

“It gives you peace of mind to work with existing technology”, Bent Lindrup adds and says that Kosan Crisplant also approached a design agency that is well-rooted in the beverage industry to assist in transferring the principles from filling beverages to those that apply for the future world sensation in gas filling plants.

The wheel is the star

The stars or star wheels that are used for distributing the gas cylinders from one process to the next became the solution that makes Flexspeed unique and dynamic. The star wheels ensure a constant flow of gas cylinders from the first to the final processing unit without stopping the movement of the gas cylinder at any one point.

A simple and perfectly innovative solution was the spark that started the inventiveness of the involved technicians.

The gas cylinders were not only to be refilled, but also tested for leakage. “Why not maintain the grip on the cylinders from the ejection star wheel over to the next process?” the team of developers asked themselves.

In traditional gas filling plants the actual handling of gas cylinders takes a lot of time. Two thirds of the time is used for moving the gas cylinders leaving only one third for processing. With Flexspeed it is the other way around.

The gas cylinders dynamically enter a star wheel with six positions and which revolves 180 degrees before the cylinders are delivered to the next process.

“This gives us the luxury of having three seconds for, say, leak detection instead of 0.8 seconds on traditional filling plants because three to four gas cylinders are inside the process module at the same time.” The Technical Director explains it this way, “This means that even when we run the system at three times the speed we did before, we now have two to three times the time needed for performing the test and so a much better opportunity to perform a perfect leak test, cap application etc.”

Intelligent features

Another essential feature with Flexspeed, and just as important, is that the gas cylinders are topped up and check-weighed as they revolve on the filling carrousel.

“When we figured out how to check-weigh the cylinders, we thought, why not simply just do it on the carrousel as a pick-up solution?”

The check-weighing and the topping-up of the cylinders were integrated in the filling process. Bent Lindrup illustrates the process in more detail.

“The gas cylinder sits on a platform that is zero-set at the introduction to the carrousel. The platform is hanging in a parallelogram. There is a wheel below the filling unit that runs on a rail that is cut in five places. These five locations are supported by a load cell.”

“Once a filling unit enters a section supported by a load cell, it has 30 to 40 mm of free running trail with full load on the cell. The longer running time we have on the load cell, the more time we have for registering the value and calculating the correct weight.”

Topping up filling

“A gas cylinder is introduced to the filling unit after the zero-setting of the filling unit. We now know the volume of residue gas and how much gas we need to fill into the cylinder to reach the gross weight of, say, 11 kg. If the scale shows e.g. half a kg we need to fill 10.50 kg gas. The cylinder is filled for a constant period of time. This means that we know the exact time when the filling unit and so the cylinder enters the next load cell section. The scale, a trend scale, registers, say 5.5 kg, a value we divide by the time already used. This gives us the filling rate in g/millisecond and we can predict the filling time for the gross weight.”

“We decide to fill 100 g below the limit. The filling stops before the unit enters the next load cell section, the topping up scale, which shows that we have reached 14.4 kg. An extra 100 g is filled into the cylinder before it reaches the check-scale where the weight is registered as 14.5 kg. Flexspeed is extremely accurate and applying an extra feature the filling accuracy can be fine-tuned even more if need be.”

According to Bent Lindrup, the overall advantages for Flexspeed customers are that the system consists of but a few units; a mechanical parallelogram, a simple filling unit and a stationary high-tech weighing cell and a computer. Everything is modular which means that we can easily make a ‘plug-and-play’ replacement.”

A simple principle
The zero-set scale controls how much each filling unit weighs. It is the same principle that applies for kitchen scales that are zero-set to compensate for different types of bowls or containers.
The tare value of the filling unit and the tare value of the gas cylinder are added to the weight of the gas.

22 kg Weight, filling unit
11 kg Weight, gas cylinder
11 kg Weight, LP Gas Gross
44 kg Weight