[chich2]

Yep.
I have one which was used in a water treatment plant. It has a small diaphram that is pulsed on time and stroke intervils. Dunno how accurate it is????

Chich

[pds]

Yep.
I have one which was used in a water treatment plant. It has a small diaphram that is pulsed on time and stroke intervils. Dunno how accurate it is????

Chich

Where did you get it and how much do it costs? Do you know where can I found more informations on it and where to buy it?

[123CNC]

What is your application, filling multiple individual containers or as a controlled input into a larging system, other? What is your process fluid?

Peristaltics are used a lot for aqueous solutions. Masterflex, Cole-parmer, and Watson-Marlow are all good names to search ebay for. They make units that you can program dosage and number of fills with pauses between containers.

Syringe fillers use to be widely used as well, IIRC 'fill-a-matic' or some derivative.

Rotary lobe pumps can be used as well, but typically larger volume and for special media, e.g. high viscosity or media with solids.

You could CNC your own with a peristaltic pump head driven by a stepper or servo. I might have one of these laying around, but you'd have to work out the dosing control.

[pds]

Well, my application is quite simple. In a car running on LPG, the valve seats suffer more than when running on gasoline. To solve this problem there are some "mechanical" systems that rely on the under-pressure created by the engine to "inject" small amounts of an additive into the engine. The problem is that this systems not very reliable and not always work as they should.

So, the pump I need is just to pump very small amounts of that additive(special oil) into the intake manifold of the engine, pretty simple

I will look over eBay for those brands, maybe I find something interesting.

One other thing, what is the expected life-time of a peristaltic pump?

[123CNC]

A peristaltic is fairly durable, the dosing chamber is a durable yet flexible and replaceable hose. The manufacturer could provide better life or reliability data.

Your application sounds like an injection system would work better. A small high pressure electric pump and injector. It would be fairly simple in that your dumping into the intake with no synchronization requirement. A high pressure injection system will help atomize your 'oil' for better distribution into the engine.

You may want to post in the engine build section to get better or more specific direction. I don't think peristaltic would suit your need.

[pds]

Your application sounds like an injection system would work better. A small high pressure electric pump and injector. It would be fairly simple in that your dumping into the intake with no synchronization requirement. A high pressure injection system will help atomize your 'oil' for better distribution into the engine.

Well, I have already thought of that, but that would make a the system to expensive. One other problem is that small pump with high pressure will not last very long, thats what I think... Do you know any small cheap pump that can do this?

The injector would be also one other problem, because we are talking of very small amounts of additive... 500ml of additive should work for about 5000/6000km... thats about 0.16 ml each minute...

One other thing that would be important is that I can increase the flow when the engine is on higher speed, with a peristaltic pump, I just need to increase the RPM of it, with a higher pressure pump and an injector, I would have to control the injector or the pressure of the pump...

You may want to post in the engine build section to get better or more specific direction. I don't think peristaltic would suit your need.

I will go ask for help in the engine build section

You might try a Trico micro-drop dispenser or one of the similar brands. They have interval and volume control. There's another brand who's name I don't recall at the moment

I will search on that one too

[123CNC]

One other thing that would be important is that I can increase the flow when the engine is on higher speed, with a peristaltic pump, I just need to increase the RPM of it, with a higher pressure pump and an injector, I would have to control the injector or the pressure of the pump...

With an injector scheme, control the time open or interval between opening as a function of speed/ rpm.

You lose the advantages of atomization and distribution if you go the peristaltic route. You would need to find or design your own 12V system, motors (not so much) and drivers (mainly), or get into inverters and dc/dc transfomers to run the whole thing. I would guess this to be equally or more expensive.

I don't know off hand how high of pressure some of the aftermarket fuel pumps can achieve. You might want to search for Facet or the like.

Or perhaps the engine builders will offer another creative solution.

Good luck.