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Motor or solenoid

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baan

Jan 13, 2011
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Hi everybody,

I am not too good in electronics, that is why I ask you for an advice. For my Study I have the following dilemma:

I have designed a pipesystem, in this system a fluid will flow. But the fluid needs to be dosed. To do this there are some valve in the pipe(these can either be rotational valve or linear)

As mentioned in the titel, I am doubting to pick a motor or a solenoid(soft shift?) The choice has to be based on reliability/price/accuracy

Some points are:
- Fluids are under 3bar/40psi pressure,
- The valve can be rotational or linear,
- The solution has to be affordable, reliable and accurate.

The problem is that my knowledge is not sufficient to make a decent choice. I hope some of you can help me?

Thanks in advance,

Hendrik
 

shrtrnd

Jan 15, 2010
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Don't know your application or metering of the dosing. If dosing needs to be precise,
consider using a peristalic (metering) pump, if the dosing is also a fluid. There are
other methods if you're introducing a powder to the fluid flow.
What kind of additional information can you provide on the introduction of the dosing to
the fluid flow?
 
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baan

Jan 13, 2011
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The fluid will be water, do you need more information?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Look for an electrically operated valve that is rated for continuous operation at around 5 Bar.

Look at the specs for reticulation valves. They typically have to withstand full mains water pressure, and that is often well in excess of 5 Bar. They're also cheap because they're so common.
 

KMoffett

Jan 21, 2009
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What volume are the doses? How accurate must the dose be. How frequently does the dose occur? Is the dose fed against a back pressure at the outlet, or to atmosphere? Is the only measure of dose, volume through drop in pressure over a time period? What size piping are you using? ?????

It might help if you explained your over all project...what the whole system is designed to accomplish. It's often easier for people here to help solve your problem, than help solve your solution. ;)

Ken
 

baan

Jan 13, 2011
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Hello Ken,

The whole project is about dosing and mixing 2 waters with different temperatures, for a new type of faucet.

What volume are the doses?
From 100mL to 20L, I assume you work in oz. so 3,38oz. to 676 oz.

How accurate must the dose be?
It must be quite aqqurate ±10mL or 0,3 oz.

How frequently does the dose occur?
It is a kitchen faucet, so 10 times a day

Is the dose fed against a back pressure at the outlet, or to atmosphere?
I assume is is atmosphere, but I am not sure

Is the only measure of dose, volume through drop in pressure over a time period?
There will be a flow meter, which is also linked to the valve of course.

What size piping are you using? ?????
The innerdiameter is 12mm

I hope this is enough information, to determine which kind of motor or solenoid will be the best solution to control the valves..
 

KMoffett

Jan 21, 2009
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Is this a design for commercial use, or a class or personal project?

I think "dosing" may be the wrong approach. Dosing would imply a fixed amount of water from each water supply to achieve a final water temperature. But, it sounds like you are trying to maintain a constant water temperature from a faucet that may have a variable total flow rate...the kitchen faucet. I use flow rates from a trickle to full-on my kitchen.
First, for volume mixing to maintain a given temperature you would have to have both water supplies at known fixed temperatures. My hot and cold water supplies' temperatures vary all over the map through the year...summer to winter in Minnesota.
To me, a temp sensor (or three), a microprocessor, and two linear-proportioning solenoid valves would be a better way to go.
But then, I may be just making too many assumptions about your end goal.

Ken
 

baan

Jan 13, 2011
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Hi Ken,

I guess you just described my whole system:
To me, a temp sensor (or three), a microprocessor, and two linear-proportioning solenoid valves would be a better way to go.

So in your opinion it is the best way to use the linear proportioning solenoid? To control the flow/amount, together with a flow control sensor and microprosesor?

Hendrik
 

KMoffett

Jan 21, 2009
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Actually, I don't know if you would need a flow sensor at all. Again, an assumption: a person walks up to the kitchen sink, selects (???) the water temperature they want, then opens/adjusts a single flow control valve by turning a knob or moving a lever. The total flow is set by this valve. The temp sensors and microcontroller then adjust the proportioning valves to give the right temperature at the faucet. Does fit your scenario?

Ken
 

baan

Jan 13, 2011
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Thanks for your comment Ken and thinking along.

Actually we also want people to be able to adjust there amount, so they can choice to have for instance 200 ml(6.7oz.) of water. That is why I wanted to add a flow sensor.

Hendrik
 

StanUlam

Mar 1, 2024
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Do you have machine shop facilities to make up prototype mechanics? If so, what about dismantling a domestic shower mixer and see if you can remove the bimetal thermal actuating mechanism and incorporate some form of electric motor drive to the mixing valves?
 

StanUlam

Mar 1, 2024
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For a proof of concept device, what about flexible neoprene tubing of appropriate size (perhaps some experimenting needed) and a model aircraft RC actuator? The actuator can drive a small bar across the neoprene tubing to restrict the flow. Use an Arduino or similar to monitor temperatures and control the actuator. The benefit of using a model aircraft actuator is that they come with their own position feedback potentiometers, and there are a number of programs to control them with Arduino in the public domain.
 

Alec_t

Jul 7, 2015
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So in your opinion it is the best way to use the linear proportioning solenoid?
I would definitely go with a linear system rather than your 'digital' version. Switching valves on and off quickly and repeatedly to get a chosen flow rate/quantity at a chosen temperature would be noisy and result in rapid valve wear.
 

bertus

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Nov 8, 2019
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hello,

this is an 13 years old thread.
time to close.

bertus
 
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