Solenoid valves

Projects General Guidance
1

I'm using a peristaltic pump to pump viscous and sticky fluids through some tubes. I need to be able to turn the "tubes" on and off, and have been using solenoid valves - which works great.

However, I'm worried about this in the long term (and I have only purchased a small number of valves or testing purposes currently). Soda syrup is the medium, and I feel that it is going to easily gum up the valves and they will fail or need to be cleaned rather frequently. Before I go and purchase 20 more of these valves (only about $6 a piece, but that still adds up quickly) - I want to make sure that I address this potential problem.

So I started researching types of solenoid valves, and I discovered there is a "solenoid pinch valve" which allows the liquid to never come into contact with the valve itself (the same reason I decided on using a peristaltic pump). However, everywhere I look, these things cost $50+ per valve. That's insanity! Why are they so expensive? Anyone have any ideas for how they could be cheaply DIY'ed? Custom manufactured by a local business? Or is there a cheaper type of electronic valve that could accomplish this? I'm kind of stuck at the moment...

Thanks

2

Economics is all about a triangle involving supply - demand - price. Things are what they cost because that's as much as people will pay.

On a more practical note could the arm of a servo be used to pinch a tube?

...R

3

May be you could use some kind of cam shaft arrangement, controlled by a motor.

4

Generally any type of valve or component that the food product passes through should be rated for 'food safe' for possible health reasons above just plugging concerns. Pinching the tube with a servo sounds like a good possible solution as servos can be found for just a few dollars these days.

Lefty