A leading company in the UK’s industrial waste management sector are the market leader in manufacturing alternative fuels for cement kilns to substitute their coal needs to maintain access. They also boast the UK’s largest physicochemical treatment facility, and operate one of only two high-temperature incineration plants nationwide.
Application Details
Mixed acids and bases are travelling through the 22 different normally closed Pinch Valves on this site, at ambient temperature. The pressure of the acids flowing through the pipework is 1.5 BAR. There is a very slight degree of vacuum being used at 0.1 BAR. On average, the amount of cycles that each valve performs is only likely to be 2 or 3 per day.
The valves are all linked to a central manifold, consisting of a pressure line (Hydraulic) and a vacuum line. Each valve is linked to a pair of solenoid valves connected to the pressure and vacuum lines. The valves duties are to control input and output from all of the storage tanks that are on site.
Water is used to close the Pinch Valves for acids, at 6 BAR. However, due to the AKO Pinch Valve only needing 2 – 2.5 BAR above the line pressure (which in this case is 1.5 BAR), a maximum of only 4 BAR is needed to fully close the valves, therefore AKO have advised that the control pressure is regulated down, which will lengthen the lifetime of the sleeves.
The sleeves used are EPDM, rated to 120°C.
The Pinch Valves work well in this operation as the material that is put through them has varying levels of solids, which seize up other types of valves.
Pinch Valves used within this application – VF080.04HTEC.334.30LA & VF100.04HTEC.334.30LA
VF model, air operated, bore sizes DN80 & DN100, aluminium body, aluminium flanges PN10/16 with EPDM flanged sleeve, EPDM internal sleeve.
There are a total of 22 valves on this chemical waste treatment plant currently. Positioned on the inlets to the chemical tanks on this chemical waste treatment plant, the Pinch Valves are used for shutting off lime and acid points. The plant was designed with 3” and 4” pipework, which is why two different valve sizes are in use.
Pinch Valve Vs. Ball/Weir Valve
Other valve types including weir valves, 4” PP plastic ball valves, and 6” air actuated ball valves are used on this site, but the site manager told us at AKO UK that they cause issues. The high solids in the waste that this site receives are what causes the issues – the ball valves and weir valves often clog and become blocked.
Pinch Valves were part of the original plant design. From the end user’s positive and successful experience with operating and maintaining Pinch Valves, the company will now be replacing all existing Ball Valves on site with AKO Pinch Valves to improve the performance level of the input and output on the chemical waste treatment tanks.
The Site Manager told us:
“If ball valves were used in place of pinch valves, they would require monthly maintenance plans to keep them operational.”
With the sleeve being the only wearable part, this gives the Pinch Valve in itself an excellent total cost of ownership. No additional fiddly pieces such as gaskets, studs, nuts, discs, O-rings, washers, packing, glands, screws, stems, etc, are needed with a Pinch Valve.
Some of the applications on this chemical waste treatment plant are not suitable for pinch valves however. The 6” valves are outlets for 500m3 storage tanks, which are all connected on a common line and the material is pumped out via that common line. Where the company can use pinch valves, they will.