Orifice Plates

Obviously you do need to condider both to get in the right ball park, but it depends on the application.

I could sell you a pump which goes up to 3bar but only at 40ml/minute.....

No good at all if you want 5L/min or conversely if you need 6bar

As our application varies, i.e. # of outputs run from a single valve, yes I would need to very much consider the flow of the pump. In one case, I am only feeding a single output, so flow is not much a concern but the pressure is because it dicates the flow through the plate. If I ran let's say 10 outputs from a single valve, then the pump capacity would need to be able to supply all of them at the desired pressure to meet the orifice plate flow #'s.

No need to sell me a pump, we deal in all types, from aodd's, centrifuge to peri's, so I have all the types and ranges I could possibly need. Thanks though

Sounds to me like you probably have all the expertise and experience you need. We sometimes take for granted what is to an obvious to an experienced, but to someone new to game it seems like rocket science.

The number of people I have to explain to that you can pump at more than 1bar but you can only 'suck' at 1bar.

(It was just an illustration rather than me trying to sell you one .)

Del

Del, as we've spoken before, yes, I am new to the fluids game and am learning in various ways on the fly. I do appreciate all the feedback that you provide me. The guys on this forum seem to be very knowlegable in their respective areas, so I like to get feedback from them. I'm not sure what you mean with the rocket science comment, but I can tell you that it certainly seemed that way at first. Since, I have have began studying some of the basic principles involved with fluid mechanics it has cleared up quite a bit, but I'm a long ways off from understanding it like yourself. Again, thank you for the feedback.

Sounds like you are after a variable displacement pump. A pressure compensated pump would maintain the required pressure over the orifice plate irrespective of flow but the pressure down stream of the orifice plate would vary with demand. The orifice plate would isolate the pump controller.

Why do you need the orifice plate? Could you not just go for load sensed if your pump has an LS port. Would just need to add # shuttle valves for # outputs.

Or are you saying that you have an orifice plate (to accurately meter) for each service? If so, just work out the max potential flow and use a straight forward pressure compensated pump.

I might be off the mark here through miss understanding the question. If so, my apologies in advance.

That is exactly what I did. The metering device is customer supplied, so I had to characterize it myself as they supplied me with very minimal information. All I knew was what they currently use for a pump, so I set up the sam configuration and collected the info. After I obtained that info and did the math It became apperant that pressure was the determining factor in output. My main question I guess was if I ran multiple output devices from the same feed line would pump flow come into play? I eneded up using a "demand pump" with a variable pressure setting, so based on the number of output devices, I can compensate by increasing or decreasing the supply pressure to meet the output flow through the orifice specifications.

Sounds like you have the pump side all sorted. As you will know, there are plenty of pump manufactures out there that have something to suit.

I would only be concerned with the heat generation from using orifice plates as flow control devices.

Nonetheless, good luck with it!

That should not be a concern beacuse of the cycle frequency. Approx. 2 min on 2 hours off. The bypass is internal and essentially just recirculates the fluid, and for a short period of time as well.

Sounds fine. Go for your life!