Big & complex seals

Trelleborg - Case Study -Big & complex seals
An airtight case for refrigerated vehicles  

Refrigerated vehicles require rear doors that are both airtight and easy to open and close. Trelleborg met this dual challenge for a refrigerated bodywork customizer using a sealing solution that offers superior connections and a special coating.

Keeping cool costs money. Generating cold air to maintain a constant temperature in refrigerated vehicles consumes considerable energy, the cost of which escalates if the refrigerated space is not airtight. The rear double doors are the vulnerable spot, as the door seals must fit together perfectly to prevent air leakage.

A leading specialist bodywork manufacturer for refrigerated vehicles wanted to improve their performance and asked Trelleborg’s sealing profiles operation to propose a new door sealing solution for small refrigerated vehicles.

“The challenge was to enhance the sealing performance of the doors while also making it easier to move the sashes, because it’s part of the driver’s job to open and close the doors many times a day,” says Alain Colombel, Technical Sales Representative for sealing profiles at Trelleborg, who worked closely with the customer on the project.

Putting the framework together

The sealing solution proposed by Trelleborg is remarkable for its size, complex geometry and technical precision. It consists of four different large EPDM profiles along with four different EPDM molded corners – the EPDM material was chosen because its long-term elasticity provides reliability over a long service life. The profiles are extruded and cut to length, and then joined with the corners using an overmolding process to form a rectangular frame for the inside of each door. All processing is carried out at the Trelleborg facility in Skózow, Poland.

“This is a very large rubber sealing profile frame. But at 95 millimeters, the profile itself is also very wide, “says Alain. “The geometry is difficult to extrude and vulcanize, as the profiles have 4 to 6 sealing lips, which must be straight, but as thin as possible. And connecting the vertical and horizontal profiles with the molded corners is a technical challenge requiring great precision, as all the profiles are different,” continues Colombel.

As well as securing airtightness, the Trelleborg solution also solved the closing resistance problem. “Using an advanced technique, we were able to apply the specially selected coating exactly where it’s needed – on the sealing lips in contact with the vehicle. This provides the right resistance while maintaining airtightness. It will make life easier for drivers when opening and closing the doors.”

Opening doors to a new segment

“This is the first time that Trelleborg has provided a sealing solution for the rear doors of refrigerated vehicles,” says Paul Neveux, Sealing Profiles Sales Manager for South West Europe at Trelleborg.

“To find the optimum solution in this new segment, we drew on our extensive application experience from specialized doors. We have produced large profiles for doors and facades in the construction sector and for technical doors in applications such as hospitals and laboratories.

“Our aim, as always, was to understand the customer and their challenges, and see where we could make a difference. And as a result, we have now gained expertise we can build on for other refrigerated applications.”

Our solution maintains the airtightness,
makes it easier to open & close the doors
good for the driver and the environment