30 minute dry times-with a wand!

Here is that article I promised Steamer about how to get more cfm out of his wand without a glide. That is only a small part of the bigger picture however, but this article tells how to do it.

30 minute Dry Times- with a wand!
Posted By Ken Harris on 5/20/2002 at 4:36 PM
The time has come for me to reveal to you how you can dry most of your customer's residential carpet in about 30 minutes using your existing equipment with a small amount of modification. I'm talking about using TM equipment here to do this and most of you will be able to use what you already have to accomplish this. In some cases you may need to upgrade what you are using to get down to these times. Or you could decide to use just what you have and still get your dry times down to an hour. What I'm about to say to get to this point is the result of 20+ years of experimenting with what works best to acheive this end.If you disagree with parts of it , fine.It has all been proven to do the job though, so use what parts of it that you can.


Components of the Drying System:

1) Equipment requirements
2) Vacuum Hoses
3) Water Temperature and pressure
4) Wand Technique
5) Wand requirements
6) Wand modication
7) The use of dryers


1) Equipment requirements

For most of you you will want to have a gas or diesal powered TM with a large enough blower to move about 300 cfm of air at a lift of 15"HG or higher. You will want it equipped with a positive displacement blower to do this. A 3.6 with a 288 cfm flow should be the minimum to consider, but a larger blower like the 4MP with it's 320 cfm and 16"HG lift would be better. It should be capable of hitting about 220 degrees ATM so you end up with about 200 degrees ATW with 100 ft of solution hose attached.Direct drive or slide-in doesn't matter.

2) Vacuum hose requirements

The hose should be kept at 110 ft or less for best performance and shortest dry times.If you can use it this way 90% of the time, you are doing very good. Two fifty foot sections of 2" hose with a 10 ft whip of 1.5" works best. Some would say to use 2" all the way ,but this is neither necessary or desirable. As long as it is kept short 1.5" hose is able to handle 280 cfm of airflow, and since even with a modified wand you will not flow more than 200 cfms, it does the job. All 2" hose just makes your job harder and wears you out sooner for no good reason.

Water Temps and Pressure

The reason to use temperatures of 200 degrees are two fold. First hotter water drys faster than colder water and will evaporate faster leaving less to dry from the carpet. More importantly though you need to use less water to clean the carpet because it speeds up the cleaning action of the chemicals used.The less water used the less to extract and evaporate. In regards to pressure , 300 psi at the wand is all you need. This will mean setting your pump at 450 ATM to get it.Using more than this breaks the surface tention of the carpet back faster and saturates it. This leads to longer drying.

Wand Technique

The best one to use to stop the carpet backing from becoming overly wet is backward only when the wand is on. Some say this does not clean as well. I say to increase your over-lapping on more heavily soiled carpet and decrease on lightly soiled. You will find you water lasts longer and your waste tank takes longer to fill too. Dry stroke the carpet once or twice after that depending on soiling present initially.

Wand Requirements

Most of you should be using a 1.5" tubed wand for the most comfort.Best would be a 1.75 tubed wand that will accept either size vac hose.The wand should have 3 jets on it, preferably 3 .02's. the reason for this is to retain as much heat to the carpet as possible. The greatest heat a cleaning system loses is here.The loss is around 15 degrees /inch of travel getting to the carpet.A 3 jet may lose 30 degrees travelling 2" down ,but a single jet can lose as much as 75 degrees going the 5 or more inches it must travel.

Wand Modication

If you are ever to get your drying times down to 30 minutes, you must find a way for your wand to move more air(CFMs) when it is down on the carpet working.Most wands will not flow more than 100 cfms thru the Wand/Carpet Interface(WCI) even when the TM powering it has 320 cfm and 15"HG and is operating only 100 ft of hose. The reason is that the effective area exposed to the atmosphere there is only the equivealent of a 5/8" hole. To improve this number you have to open up more area to airflow. The way you can do this easily is to take your 12" wand and turn it over . On the inner lip(the one closer to the wand jets)mark off 22 lines with a fine tipped marker pen, one every 1/2"until they go from one side to the other.Get yourself a fine hacksaw blade and say down to a depth of 1/8".This will get you about 50 more cfms entering your wand with a drop in your drying times. For those systems that you know for sure have over 300 cfms of airflow,you could increase the number of slots up to 44 to get about 200 cfm or use a fine file to double the width of your existing slots. File the edges of your air slots smooth before using it so as to not snag any carpet yarns.

The use of dryers

These should still be used with this system to get the fastest drying times. Use them in the center of the room with them pointed at the ceiling to force the airflow all around the floor to prevent a boundry layer of saturated air from forming and slowing down your drying.In some dryer climates you will find you don't need them if you are using the other parts of this drying system properly.Opening 2 windows or running the HVAC may be enough.


Ken Harris
Turboteck Supplies

    

Edited by Superglide Ken - 14/November/2006 at 9:45pm

HOT WATER DOES NOT AND WILL NEVER DRY ANY FASTER THAN COLD WATER.

Sorry Jack, but it does. The reason it does is because water that is at a higher temperature needs less latent energy to be added to it to reach it's vapour point. Most people would call this the point where it goes from the liquid to the gas phase. This does not happen in a dramatic fashion, so I dont want to put too much of a point on this because it only happens within the first few minutes after cleaning. Beyond that point, evaporative cooling is the most dominent factor at play, and temps are quickly brought to a new equalibrium.

Jack, you are a nit-picker, and I knew you would find something to question here.

KENNY........YOU ARE OMITTING TO CONSIDER THAT ONCE THE HEATED WATER REGARDLESS OF TEMPERATURE LANDS ON THE CARPET SURFACE IT VERY QUICKLY DECREASES IN TEMPERATURE THUS BEGINNING THE STAGES OF COOLING AND NOT EVAPORATION.

Edited by nightrider - 14/November/2006 at 11:12pm

WORDS CAN BE VERY TRICKY, IF I TOLD YOU THAT IF I FILLED MY POOL WITH DRY ICE WHEN IT MELTED YOU WOULD NOT GET WET IF YOU JUMPED IN.


That is because with dry Ice, there is no melting point Jack. Dry Ice is one of those solids that goes directly to vapour form by the process of sublimation.

KENNY........YOU ARE OMITTING TO CONSIDER THAT ONCE THE HEATED WATER REGARDLESS OF TEMPERATURE LANDS ON THE CARPET SURFACE IT VERY QUICKLY DECREASES IN TEMPERATURE THUS BEGINNING THE STAGES OF COOLING AND NOT EVAPORATION.

I am not forgeting that fact at all Jack. What you forget is that both evaporation and evaporative cooling both are happening at the same time. It is NOT an either/or situation. One force is stronger than the other at different points in time, but both do happen together. Initially the water that hits the carpet's face fibers get warmed up by the spray from the wand's jets. Once that happens, the water warms up the primary back of the carpet. Once the wand moves on, the water in the carpet stays warm even though evaporative cooling is taking place at a constant rate. Why? Because the carpet is warm now and keeps the water on it warm. During those first few minutes , the water on the fibers are warmer than their surroundings. It is during that time, short as it mmay be, that evaporation or drying is increased because less latent energy is required to evaporate the water off the fibers than would be the case if the carpet was cold. The rate of evaporation is a constant as you say, but only under a set sort of conditions. Change any condition, such as the amount of water vapour in the air, and the rate is changed.Heat the air higher, and the rate of evaporation is increased by that change. Unstable conditions will always find a new equilbrium to make them stable once more.Hot water is unstable. it quickly becomes cold water.Only during the warm to hot phase(minutes) is evaporation enhanced over the rate that cold water provides. Most of the time thereafter, evaporative cooling reduces temperature until humidity of the carpet is the same as before cleaning took place.

I did not want to type a 500 word essay to prove my point BTW, but I think some force me to cause they know I only type with one finger.


    
     

Edited by Superglide Ken - 14/November/2006 at 11:56pm

Jack: Science will also tell you that a Bumblebee can't fly. They even have the equations to prove it to you!

I am telling you that the evaporation of hot water is greater than that of cold water, and the effect lasts longer than 30 to 60 seconds. 25,000 houses cleaned doing it both ways and using a carpet thermometer tells me I am right about that.The time it takes for the carpet to reach a "cold temperature" however, is usually 5 to 10 minutes. Since that period of time represents only 5% of the time (on average) of the total time the drying is taking place, I think we can both agree to the following to stop this nit-picking:

Hot or Cold water has only a minor effect on the total amount of time that carpet will take to dry, BECAUSE for at least 95% of the time while the drying is happening, the water IN THE CARPET is cold anyway in both situations.

However, that is in theory only. In the real world, there is a greater variation than 5% in dry times between cleaning a carpet with cold water than using hot water. This is because the cleaning power of hot water is greater. Hot water means you go over the carpet less to get it clean. Less water gets into the carpet back because of this, and dry time of the carpet is at least 10% faster because of that. In an owner occupied home, 10% or quicker dry times can be meaningful to some people.

Nuff Said.


    

Edited by Superglide Ken - 15/November/2006 at 12:52am

I think the point your missing NR is that it's pressurized hot water..much different from normal plain old hot water...

the water must be under pressure