Valve for Metal Powder in Chemical Processing

A chemical manufacturing company have been using an AKO Pinch Valve within their free flowing solids application for one and a half years. They were previously using slide valves (also known as knife gate valves), which were not sealing very well. The company needed a better seal, which is why they switched to AKO Pinch Valves.

The free flow solids within this application, including metal powder, are travelling through the pinch valve at gravity flow, with 5 BAR being used to shut off the rubber sleeve. The pinch valve is held in the normally closed position, and carries out 6 cycles per day.

This application is at potential risk of explosive gas or air mixtures in the atmosphere, and so the pinch valve needed to comply with EX regulations for EX Zone 1.

Pinch Valve used within this application: VFX150.03LF.35.30LA

VF model, EX conformed, aluminium body, aluminium PN10/16 flanges with stainless steel bushings, natural rubber conductive sleeve.

The previously installed slide valve was gradually becoming fouled with the metal powder that runs through the valve and pipelines, so the valve would not seal properly, resulting in cleandowns every 15 or so batches of product. This was not ideal for the chemicals manufacturer, and was causing delays in production with the increased downtime.

The engineer we spoke to on site was very happy with his experience of the performance of the pinch valve:

Pinch Valve accessories such as a pressure switch and a solenoid safety arrangement are also used in this application. With the safety arrangement, the pinch valve remains closed in case of loss of power or air.

Reliability with Pinch Valves for Chemicals

Because of the abrasion resistant rubber elastomer used within the heart of the pinch valve, the metal powders and other abrasive media can travel through the valve bore at ease, with no blockages or harsh wear. The wetted parts of the particular pinch valve used within this chemical manufacturing application are stainless steel bushings on the flanges, and the conductive black natural rubber sleeve. Therefore the metal powder does not come into contact with any aluminium parts of the valve.

The rubber sleeve is the only wearable part of the pinch valve, which over time will need replacing, depending on the amount of cycles performed. To date, after 18 months this pinch valve has not needed to be removed from in-line for any repairs other than general service checks maintenance.