Damper on PW????

[Clean County PW]

Is it that critical to have a damper or whatever they call it on the powerwasher when using 200' or more PW hose when in use??

Most of the time I use 200' of PW hose. There are times I use 300'-400' of hose and I never had a problem with spikes. Now I'm hearing that these spikes can cause pump damage and could actually be dangerous.

Any truth to that??

Also is it recommended to have this damper and what do they cost?? Also where would they be placed on the powerwasher??

 

[beyoungsr]

John T.,

I am waiting to hear the same answer. I occasionaly also have long runs of hp hose. Been doing that for eight years now.

I cant find anything that reccomends it. I have heard about it in the car wash industy. They use mainly use on incoming water supplies to the pumps.

I sure don't want to run with something that is unfounded.

Tony at A-Plus said his All American machine came with one on it.
His unit also has a flow unloader.

I think I will send Richard Craig-Pro Wash an e-mail.

 

[ron p]

the info came from EPP'S

MICHEAL at EPP'S has said that the operation of the trigger gun at hose langth's over 150 ft can cause a 4000 psi pressure spike to hit the pumphead and blow out the seal's.
Dave Olsen think's it's important enuff to have a $800 one installed on his pump.
Mark at easy-clean think's it's important enuff to install them.
Micheal at EPP'S think's it's important enuff to install one.
Im getting ready to start useing up to 300 ft langth's, so i was just reading-up on it and posted my finding's.
These bladders are shock absorbers.
I rather pay $100 [whatever] to not have my pump break on a job where im 1/2 done and 50 miles from home or a repair shop.
Read "what hose langth can I use" on delco's oldest bbs.

 

[beyoungsr]

Ron,
I am not arguing with you but rather trying to understand the need.

I don't seem to find them in the literature for any of the machines EPPS, Easy Clean, Envirospec or Delco sell.

If the need is that great wouldnt the manufactures install them purely for liability issues. If they didnt shouldnt the owners manual explain the potential hazard?

Hopefully someone can explain why we need the damper.

 

[booyaa]

http://www.process-controls.com/Vissers_Sales/Blacoh/

There's a link that should explain it.

I've not seen the "pressure spike" that's talked about around here, but I'm sure that it could happen.

I've always had a pulsation dampener on my machines.

 

[ron p]

im just looking into

this myself.
Somewhere along the line, ive read that guy's were knocked 15 ft from a water spike.
As a matter of fact is was scott stone.
I bet you he has one installed on his unit now.

 

[oneness]

I wonder if it matters what kind of unloader you have? I have the type that when you pull the trigger, you don't get pressure right away.

 

[ron p]

ron p

oneness, im not sure but is a $40 unloader would fix the problem why would people be buying the damper for much more then that?
Anyone where the WIZ went?

 

[Dave Olson]

Hello Guys,

The dampener that we have on our pump is primarly because it is a duplex rather than a triplex pump. It may help with spikes but we have always had one on this pump so really don't know any different!

Dave Olson

 

[Hotwaterwizard]

Right or wrong here is my opinion on the matter:

1) How can there be a spike on the pump from the hose if there is an unloader between the pump and the hose? The unloader stops the pressure from returning back to the pump head because of the check-valve on it's output.

2) I have customers that run 500 to 600 feet of hose with no problems eccept they loose 1 pound of pressure per foot of 3/8 hose. With a gauge on the pump there is no spike present to support the theorys that you guys are stating. A 400 psi deadband spike is normal for a lock-up unloader.

3) pulsation dampeners are normally used to remove pulsation on a coil to reduce wear and tear not to remove a spike. They are used to smooth out the water flow like a shock on a car makes the body have a smoothe ride. They also smothe out the flow of water so you can get an accurate reading on the pressure guage.

4) If you have a flow unloader the pressure will release as the flow thru the gun is on or off with very little spike.

5) The main reason for spikes are caused by improper unloader adjustment and wrong tip sizes. A properly adjusted unloader will release within one second of the release of the trigger. If you can count to 2 then your unloader is not adjusted properly and there lies your problem.

6) A hose acts as a natural spike/shock absorber, it expands and contracts as pressure is applied and released from your trigger gun. If you don't believe that look at the hose when you use the pressure washer. With that in mind imagine for a second the differencees in a short hose and a long hose. The short hose has less area to expand and collapse than a long hose so , with that in mind a long hose will dampen the spike way better than a short hose will. This is why the manufactures of paint sprayers always suggest using atleast a 50ft hose when using an airless paint sprayer. It puts out between 1500 and 3000 psi just like a pressure washer does.

You don't need to waste your money on something you already have designed into the system! The longer the hose the better the ability to absorb the spike.

 

[booyaa]

Wiz

A few times in my career I've lost the nitrogen charge in my PD's and the difference in feel at the gun was not uncomfortable, but pretty noticeable. There's a definate "pulse" that isn't there when the thing is working right, and that's with the unloader adjusted correctly.

So yeah, I agree with you that it's just there to smooth things out.

I've heard a few people talk about the "spike" and that amazes me. Imagine that happening in a cherry picker near the top of a big building.

 

[beyoungsr]

WIZ.
Thank you very much for the detailed reply. I assumed the effect would also be woarse with a shorter hose. I also had suspicion that the unloader would absorb some or all of the shock and pass it on to the tank if plumbed that way.

Ok so problem solved and no worries.

Hey which is your preferance a flow or pressure unloader??

 

[ron p]

Ron p/Scott Stone

i was sure Scott posted that that a spike had tossed him 12 ft.
Did'nt even know what hit him.

 

[Hotwaterwizard]

WIZ.


Hey which is your preferance a flow or pressure unloader??

Wow that is a good Question.
Both types have their advantages and disadvantages.
I think if I had a machine of my own I would want a pressure unloader on it.
These type have less problems and work better for long hose runs. Flow unloaders don,t work well with long hoses.

 

[oneness]

Ok, which is a flow type and which is a pressure type? When I pull the trigger, the pressure takes a moment to kick in. I've used other machines where the pressure is there the instant you pull the trigger. Which is which?

Thanks!

 

[beyoungsr]

Oneness,
The instant pressure is the pressure type. The flow type has the slightly delayed response.

 

[Hotwaterwizard]

They say a picture is worth a thousand words!

 

[concretecurt]

Right or wrong here is my opinion on the matter:

1) How can there be a spike on the pump from the hose if there is an unloader between the pump and the hose? The unloader stops the pressure from returning back to the pump head because of the check-valve on it's output.

2) I have customers that run 500 to 600 feet of hose with no problems eccept they loose 1 pound of pressure per foot of 3/8 hose. With a gauge on the pump there is no spike present to support the theorys that you guys are stating. A 400 psi deadband spike is normal for a lock-up unloader.

3) pulsation dampeners are normally used to remove pulsation on a coil to reduce wear and tear not to remove a spike. They are used to smooth out the water flow like a shock on a car makes the body have a smoothe ride. They also smothe out the flow of water so you can get an accurate reading on the pressure guage.

4) If you have a flow unloader the pressure will release as the flow thru the gun is on or off with very little spike.

5) The main reason for spikes are caused by improper unloader adjustment and wrong tip sizes. A properly adjusted unloader will release within one second of the release of the trigger. If you can count to 2 then your unloader is not adjusted properly and there lies your problem.

6) A hose acts as a natural spike/shock absorber, it expands and contracts as pressure is applied and released from your trigger gun. If you don't believe that look at the hose when you use the pressure washer. With that in mind imagine for a second the differencees in a short hose and a long hose. The short hose has less area to expand and collapse than a long hose so , with that in mind a long hose will dampen the spike way better than a short hose will. This is why the manufactures of paint sprayers always suggest using atleast a 50ft hose when using an airless paint sprayer. It puts out between 1500 and 3000 psi just like a pressure washer does.

You don't need to waste your money on something you already have designed into the system! The longer the hose the better the ability to absorb the spike.

I believe the physical fact is this, the longer the hose the more volumn of water you have that is considered energy( x number of pounds/liters/gallons of water) moving at a given speed depending on hose diameter and gpm/psi. Then that flow is suddenly stopped, creating a large amount of energy to be transferred both forward and then rebounding in reverse direction.