In-bay dryer

[Bubbles Galore]

I know this issue has been beat to death lately, but why would it be difficult to build your own? Either with some type of electric leaf blower motor or a side discharge vac motor, mercury relay, mosmatic air boom, and some vac hose and you're set to go? I believe you can buy the replacement air shamee guns from KR, so I just can't figure out why more operators don't just build ther own.

I had Mike Doyle (great guy) out at my suite demo'ing a blasto dry unit and it just doesn't seem to complicated. As much as I would like to offer Mike some business, I feel as though I can spend 25% of the price and build my own. Money is always a factor and this would greatly increase the ROI of a unit.

Am I missing some key component here or what?

Thanks in advance.

 

[bigleo48]

Bubbles,

Nope...mine is three side discharge vac motors, relays, air plumbing, booms and gun. Nothing complicated here and I would definitely build my own if I was to do it all over again.

Big

 

[Bubbles Galore]

Would you advise going with three motors? I was unsure of how many motors were needed to get the proper cfm. Do you run yours on a 30 amp circuit? Thanks big, I owe you a few beers now.

 

[MEP001]

If your power is 208 with three separate 120V legs, you should be able to run three motors off the same breaker as the bay motor. You'll only need to make sure the dryer and the pump are never on at the same time. If your 3-phase has a high leg you'll have to breaker them separately.

 

[Randy]

Years ago at the ICA conventions there was this nice older gentleman who sold vac hose, I don’t remember which company it was but Smooth bore sticks in my mind. He used to laugh when people would ask him about 3 motors vac’s over 2 motor vac’s. He would always explain that no matter how many motors you have on a 2” vac hose you can only get 210 CFM’s through the hose. He used to be at all the conventions, I'm sure he's long retired now.

 

[MEP001]

Years ago at the ICA conventions there was this nice older gentleman who sold vac hose, I don’t remember which company it was but Smooth bore sticks in my mind. He used to laugh when people would ask him about 3 motors vac’s over 2 motor vac’s. He would always explain that no matter how many motors you have on a 2” vac hose you can only get 210 CFM’s through the hose. He used to be at all the conventions, I'm sure he's long retired now.

That's ignorant bull****.

 

[Earl Weiss]

That's ignorant bull****.

Perhaps, but perhaps not completely. I have heard it before (not with a specific CFM) but there does seem to be diminishing returns. Seems it is complicated vis a vis CFM and suction force or in this case blowing force.

Think of it like plumbing. If your water is at a certain pressure, if you hook up a 2 inch main or a 4 inch main at the same pressure and hook up a 1/2" pipe to either, the flow won't change much. So, now it is a function of not just increasing flow volume but weather or not the third motor will increase the pressure in the hose. So, I would think there might be some complicated figuring to do. (BTW my 2 and 3 motor vacs use the same motors and there does not seem to be 50% more suction (or even 1/3 more) with 3 vs. 2. - Totally unscientific analysis.)

 

[MEP001]

Diminishing returns, yes, but unless you're creating an absolute vacuum in the tank with two motors, the more CFM being pulled out of the tank the more air will get pulled through the hose.

 

[Jeff_L]

I'm not a physics major, but do believe in the diminishing return on more vac motors. However, I like three motor vacs more for a different reason, and that's redundancy. On a two motor vac, if you lose a motor the customer notices immediately and you look like crap. On a three motor, you can lose a motor without the customer really noticing. That way you can replace it after they are done with little to no impact. All about the customer experience.

 

[mike_d]

I've spent a lot of time dealing with this issue and feel compelled to comment.

The flow of air through a tube in an application such as vacuum cleaning (or the reverse blowers for drying) is actually extremely complicated. In contrast with liquids (water, soap, etc.) air is a compressible fluid. This completely alters the dynamics of the actual flow through tubes, pipes and nozzles - "compressible flows" vs. "incompressible flows". It is enormously more dependant on factors such as tubing size, flow conditions (laminar v. turbulent flow), and pressure. For example, measuring flow through a vacuum hose that is laid staight vs. coiled or contorted as in use results in measureable flow changes when checked with a meter. Other examples, are automotive intake and exhaust system design for best flow - high performance headers, manifolds, etc., industrial ventilation system tuning and design for efficient flow v. plumbing. Furthermore, the typical air flow producers (vacuum blowers and the like) are not positive displacement pumps and simply allow for "slip" at flows approaching fan design pressure (vacuum) limits. In consideration that mathematical models to solve these issues involve some of the most advanced fluid dynamic and thermodynamic calculations, we chose to use some basic experimentation in our quest to develop a useful drying nozzle and blower combination. After some very basic flow - orifice calculations, we used a water displacement test setup to determine the best combination of nozzle design and blower combination. It was our findings that after a certain level of flow was employed (volume) that it was the component of greater fan pressure that resulted in further performance improvement. Based on these tests, I feel that this would also apply to vacuum cleaning - i.e., it may be of more advantage to use two blowers of higher pressure (greater vacuum) than three motors of lower pressure (lower vacuum) - provided that both setups provided adequate volumes to approach tubing limits with the pressure change ranges. Applying our test to vacuums would be complicated by the necessity of measuring the exhaust and not the actual working airstream.

In short, I feel that the "old vacuum hose saleman" was guilty of only slightly overstating the case and that Earl's findings concur with ours.

 

[mjwalsh]

Based on both science & experience

Mike_D,

Great work on your series in the Auto Laundry News on Hand Held Blow Drys! Often us operators need to look beneath the surface & not just over simplify things. You know the saying "Ignorance can be Bliss"!

I remember working with a mechanical engineer to resolve a botched boiler installation job & the engineer's frustration with the contractors when they would not factor in all the elbows & the type of elbows etc. I guess they thought they knew more than the laws of physics, nature, & balancing factors etc!

P.S. We have not forgotten about you. Our dog wash turned into a lot more details (hopefully worthwhile though) than we planned & we are now in the middle a mind boggling spruce up of our payment acceptance in the car wash & a very intricate laundry equipment update. Your '80s era Doyle Vacuums are successfully updated with Multi Coin Acceptors & Dixmors with displays & bonus allowed --- that was our first step.

We are a little nervous about the 2 inch hoses being too awkward vs our existing 1.5 inch hoses. Also we are hopeful about being able to use our existing 3 motor sealed boxes of our 300 CFM Specialty Blow Drys that are still operational & being used since 1987. Maybe they can be temporarily taken down & extended by a local fabricator on their depth??? The 20 amp breakers - 12 gauge solid wires make me nervous a bit too though. I suppose those older low profile 112393 Ametek motors don't have the "pressure output" to do as well possibly as the currently optimized motor options??? If I did not already have blow drys like Bubbles Galore's situation I would be leaning towards getting a "turn key" from you.

MJ

 

[SuperClean]

Bubbles,

Nope...mine is three side discharge vac motors, relays, air plumbing, booms and gun. Nothing complicated here and I would definitely build my own if I was to do it all over again.

Big

You wouldn't have any drawing available i wouldn't mind giving it a try.
Greig