Aggressive black wash safely pumped by Verderair Pure

In the casting industry after the casting moulds are formed, the moulds are treated with ‘black wash’ to achieve a smoother surface. As a result the final product has as few imperfections as possible. The black wash contains very abrasive particles that have a bad influence on the lifetime of the pump.

The process

Black wash is pumped into a wash bath where the moulds are immersed. The black wash coating polishes the rough finish of the form and the core. The core and casting surfaces are even and smooth upon removal from the wash bath treatment.

The problem

The customer used a standard model double diaphragm with stainless steel housing and seats, balls and diaphragms made of Buna. The pump is operating 15 hours a day, 5 days a week. The engineering manager found that due to very abrasive black wash the balls, seats and diaphragms suffered excessive wear with replacements required every 6 weeks.

The solution

The customer tested a VA-P25 PE pump with PE seats, EPDM balls and diaphragms. This pump ran for 10 weeks before it broke down, a working cycle increase of almost 70%. The Verderair Pure with PE has a better abrasive resistance than a stainless steel double diaphragm pump. Our customer was very satisfied as the production downtime was minimized and the spares cost was greatly reduced due as the pump contains fewer parts and the long service life of the diaphragms.


✔ Less wear
✔ Less maintenance
✔ Less changing parts
✔ Less money spent!