Monthly Archives: June 2020

New rotating distributor handles up to 70% more strain and stress

At Hydria Water, work is constantly ongoing on the innovation and development of working methods and products for the future. When one of our clients experienced unforeseen problems with a rotating distributor and needed a more robust machine due to strong winds, the engineering department designed and built an entirely new heavy-duty rotating distributor.

– It was designed to be able to withstand both high winds and uneven loads. We have developed the design to have, among other things, a new top layer, and a created a machine that can handle 60–70% more strain and stress with the same component costs, Andreas Riedel, Technical Manager at Hydria Water, says.

Andreas explains that the engineering department works as a team; they first sketch proposals for products that they wish to create and then model them using simulation software. They then discuss their design, and following consultation with the client go forward with one of the suggestions – in this case a prototype heavy-duty rotating distributor, which has been installed and operational for a year at a wastewater treatment plant in Gnosjö, Sweden.

“The first machine we delivered to the Braviken paper mill ran practically flawlessly for almost 50 years”

The Braviken paper mill near Norrköping, Sweden employs 400 people and is one of the world’s most efficient paper mills in terms of production. In 1972 Hydria Water delivered a machine to the paper mill, and this year, 48 years later, they delivered a replacement machine.

– The previous machine ran practically flawlessly for almost 50 years – that is a good grade to have achieved, Hydra Water’s Technical Manager says with a smile.

The new machine is a 17-metre long, custom-made overhead travelling carriage with a sludge suction pump that purifies the water used in the mill’s processing.

– The sludge suction pump functions a little like a vacuum cleaner, purifying the 55°C process water of cellulose fibres. The basic function is the same as for the previous machine, but the new one has a more modern design and new, acid-resistant components.

The previous machine was constructed using black steel, and when the components began to wear it was felt that it would be better to upgrade to a new machine rather than renovate the old one. New technology, new materials that handle process water more efficiently, and a new, more compact control system, resulted in a great improvement for the paper mill as a whole.

– It’s a marked difference: we have moved from a control system the size of a small garden shed to one that measures 80 x 80 centimetres. We are good at technology, and much has changed over the past five decades.

The new machine was installed at the end of April in a water-filled tank.

– There were special requirements during installation, and it was not possible to empty the tank, which is normally done during installation, or even lower the water level. As a result, we installed it in a water-filled tank this time. Everyone involved rose to the challenge in an admirable way, Andreas concludes.

Photograph: Braviken

Field testing in Rävlanda, Sweden – “Visible results in just two weeks”

Since February, Hydria Water has been conducting field testing of channel filters at the Rävlanda and another, as yet secret, patent-pending solution at the Rävlanda wastewater treatment plant.

– Previously there was an older mechanical step-type screen; now the water from the pumping station is directed to our channel filter, which is the first part of the wastewater treatment plant and handles around 3500 pe, Rikard Karlsson at Hydria Water explains.

In 2019 the wastewater treatment plant filtered a total of 550 kg material, but with the new channel filter the screening has become almost too efficient, and in just two months 450 kg material was filtered.

Patrik Eliasson is an operations technician at Rävlanda wastewater treatment plant. He laughs when he remembers the panic-purchasing of waste containers shortly after the new machine had been installed.

– Before, two waste containers per week was enough, but with this machine we need six waste containers a week!

The field test is the largest that has been conducted at the plant since it was renovated 20 years ago, according to Patrik.

– I’m delighted; the process has been entirely smooth. The old screen is about to give up, but now I don’t think I would want to go back to that type of solution again. The technology and results are better with this solution – in addition, there is less sedimentation of sand and gravel in the machine than before, he says.

– The pre-sedimentation tank is cleaner than before, as is the picket fence thickener. It took only two weeks for a change to become visible in the sedimentation tanks and sludge; now, the amount of rags and cotton buds is vastly reduced.

Between February and the middle of May, the machine operated for 130 hours. The project will be concluded by the end of the summer.

– We are very grateful to have been given this opportunity. We’re very happy with the collaboration and feel that it has worked very well; the plant is situated in our local area, and provides us with opportunities for exciting product developments, Rikard says.