What is the name of this valve?

[PBTech]

I am looking for a plastic ball valve I believe. I can't think of a name that would fit this. The situation is this: I have a machine that runs sealer fluid from a reservoir through a 1/4" hose up to a pump and through another 1/4" hose up to where the fluid is needed in a smaller reservoir. There is also an overflow hose on the smaller reservoir back to the larger reservoir.

The problem is when we remove the large reservoir to refill it; the pump looses its prime. Usually I swap the two hoses, on the pump, for a second, to get fluid to run back down through the hose, and then I swap the hoses back on the pump to run.

I am looking for a valve that has two positions. One position where two hoses go in and pass straight through to two outputs. And the second position where the outputs are swapped.

This way I could prime the pump simply by turning the valve for a second, then turn it back to run. It would be a sealed system and not a wet mess like what I am doing now.

Any suggestions would be greatly appreciated.

 

[jmw]

Why not fit a non-return valve in the feed to the pump? This should keep the hose flooded whle you change the reservoir.

JMW

http://www.viscoanalyser.com

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[PBTech]

What is a non return valve?

When the bottom reservoir is removed, the hose starts sucking air through the pump. I don't see how to stop the air?

I did some more research; it looks like I would need a 4-way crossover valve. I am having a hard time finding a plastic low pressure one for fluid that would have nipples to put the hose over instead of threads. I would think something like this would exist for laboratories?

 

[PBTech]

The flow of the pump is very low, I am worried any one way valve would possiably halt the flow all together.

 

[jmw]

Ah! the pump continues to run while you change the reservoir.
Then a non-return valve would not work. If the pump is running then it will draw air through this valve.

The non-return valve would prevent gravity drain out of the hose when the pump is off and the main reservoir removed. Of course, if this is why the pump must be kept running, then you could fit the non-return valve and swicth the pump off when you come to change the main reservoir.

If there is some other reason why the pump must continue running, I would suggest you need a hose from the top reservoir (not the overflow since I assume this only flows product when the small reservoir is full, but one from the botton of the small reservoir that can always draw fluid.

Now, between the bottom resevoir and the pump inlet you have a 3 port ball valve. In position (1) it draws the fluid from the main reservoir. In position (2) it draws fluid from the small reservoir and allows you to disconnect the main reservoir to replace it.

However, it may be important to know why the pump must be kept running since this may impact on why this solution might not be appropriate. For example, if the fluid has a tendancy to set up if statid e.g. in the pump chamber, then when drawing from the main reservoir the fluid in the return from the top tank (that i propose is connected to the three port ball valve) would be static.

JMW

http://www.viscoanalyser.com

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[jmw]

PS a quick Google produced this link top of the list:

http://www.plastomatic.com/tabv.html

You could also have a manual valve.

JMW

http://www.viscoanalyser.com

Eng-Tips: Pro bono publico, by engineers, for engineers.

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[PBTech]

This system is a sealer unit for a High Speed Pitney Bowes inserter. I am a service tech on these units. The operators that run these units do not have access to where the pump is plugged in, so when they refill the reservoirs, they loose the prime. I am just trying to come up with easy way for them to reprime the pump with out my help.

It seems like if I put a y connector on the hose between the pump and the small reservoir, and run a hose off of that to the 3 way valve you are speaking off right before the pump on the line to the big reservoir, I should be able to get a prime.

Now it is just a matter of finding a place that sells the valve and y connector. Shouldn't be that hard. I guess maybe something like this for aquariums maybe?

I still would like a 4 way cross over, just because this method would get fluid through the pump. But I would think if the water was within a inch of the inlet, it would prime.

 

[MikeHalloran]

Having the operator physically remove the reservoir from the machine to refill it, and using a non self- priming pump, and not providing a local shutoff switch, does not speak well of the machine's designers. Maybe if they changed a few reservoirs themselves, and spilled the stuff on their shoes, and had to reprime the pump, and ... well, you can't fix corporate culture problems from where you are.

Given that the operators accept switching reservoirs without protest, you could provide a second reservoir that they could pre- fill, and swap out quickly.

Or, you could put a hose fitting in the top of the reservoir, leave the reservoir in the machine, and siphon the fluid from a barrel. Does it arrive in a barrel? Why doesn't it arrive in a new reservoir?

Or, wait a minute. If the pump can't prime itself, then it might not be harmed by running with the inlet shut off for a short time. You could just put a plastic ball valve in the pump suction, and instruct the operators to close it while they change the reservoir, then reopen it. You didn't mention what kind of pump it is; some wouldn't be particularly bothered by a having their inlet strangled for a little while; some would. You probably should ask the factory wonks if it's okay before actually doing it.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[PBTech]

This is a pretty new inserter. Originally there was a small rotary pump, which had no problem repriming its self, but this would run backwards occasionally due to a design flaw when the machine was repowered. Now we use a small vibrating pump. I believe the reason the pump can not be switched off is because if it is forgot about, they could run 1000 pieces of mail easily before figuring out the pump is off. I just figure a valve and some extra hose would be a simple fix with out trying to find a alternative pump or redesigning how the operators have to refill the reservoir.

The sealer fluid comes in barrels, but there is no room around the machines to put a barrel, as I have to have access to all of the panels for maintenance.

 

[CRG]

PBTech,

Did you try a google search for "four way ball valve"
I had 35 hits.

Or you might be able to use two three way valves with common accutaion linkage and a couple of tees.

 

[jmw]

PBTech,
This is what happens when the original problem, which you describe as a "design flaw" that allowed the original pump to reverse it-self when re-powered, is not resolved.
The "solution" adds new problems rather and the ultimate cost of the solution often exceeds the cost of putting right the original problem.

[ul square][li]How did the original pump manage to run backwards when re-powered? [/li]
[li]Why was this so dificult to fix?[/li]
[li] Why did the manufacturer not fix it?[/li][/ul]

Now, because of a design flaw, you have the situation where you get a mess on the floor, wasting sealant, and you run the risk of emptying the machines smaller reservoir while you change out the main reservoir.

I did wonder why the machine has a reservoir.
This could be to provide continuous operation while the supply reservoir is changed, in which case this and the pump arrangement would be standard equipment from the supplier.

But if i had to guess, It could be because these machines are often installed in banks by a mailout specialist with many such machines running at once and all supplied from a common supply tank via pressuriised or gravity feed lines sized for the average hourly consumption rate and not the instantaneous rate when sealant is dosed and a protection against all the machines dosing at once.

I would then guess that this is a singleton machine for your companies own mailouts, the pump and the overflow lines are the work-around provided by your companies engineers or a third party (posibly there was a float valve in the machines reservoir to control the inflow of sealant and this has been removed).

I could be wrong.

Speculation aside, I think the best solution would be to try and get the rotary pump working as this is self-priming. Incidentally, from your description you appear to try and change the supply reservoir while it still has product left in it. How does the operator know when to change it? Why change it with residual sealant left in the tank and lost? Since you lose the flooded suction anyway, why not run it until the paump draws air from the empty container and change it then?

Would I be right in thinking that sealant is supplied is top entry drums?
One option is to get a drum pump which is designed to be top inserted and self prime, another option would be to purchase sealant in returnable bottom-outlet tanks that can be positioned using a pallet truck. When you couple up to these you will get a gravity feed to the pump inlet (if the pump is on the floor) which will overcome the priming problem.



JMW

http://www.viscoanalyser.com

Eng-Tips: Pro bono publico, by engineers, for engineers.

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[zdas04]

PBTech,
You've gotten a lot of good advice about re-designing the process, but sometimes a significant re-design is outside an individual's direct control where a work-around might be within his control. JMW is correct that a "simple" fix will often put you deeply into the law of un-intended consequences.

If you want a 4-way valve to address what may be just the next step in what will eventually be a complete re-design, I'd look at

http://www.westernanalytical.com/rheodyne/acrobat/SB_58-59.pdf

I've never used their products, but the description looks to be quite competent.


David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The Plural of "anecdote" is not "data"

 

[ApC2Kp]

PBTech,
Take a look at the

http://www.usplastic.com

site for tubing, hose, plastic pipe, and valves. There is a polypropylene Elliptic valve 3-way 4-position that you might consider. Ther are also 3-way valves in the pipe and valve setion. It might be possible to link a pair of 3-way valves together to accomplish the switchover you are needing.
Another small item to reduce spills would be hose couplings with shutoff valve in the coupling - see the CPC quick connect tube fitting products.
If the fluids are compatible with 316SS, there are the plug valves - Whitey by SwageLok Co.- that are offered in 3,5,7 way patterns. Other tube fitting valve suppliers have multi-port valves for mainly instrument control purposes. Try ASCO solenoid if you want to make a remote switchover.

 

[jsummerfield]

I did not see the words spool valve or shuttle valve. Google these.

John