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Part 2 / Low vs High pressure portable extraction machines

The second part of our experiment to establish true flow and pressure at the tool end on portable extraction machines fitted with Low and High pressure pumps.

When I was out earning a living professionally cleaning carpets and upholstery in the 90s I ran several different portable extraction machines. These machines were adequate and allowed me to overall achieve great results. Where I became frustrated was when I was trying to rinse out heavily soiled commercial carpets.

I’m sure we have all be there at one stage where we have been asked to clean a hotel, restaurant or pub fitted with a quality commercial grade wool carpet. These carpets heavy wool content act like sponges and will absorb vast amounts of liquid. Some of the most challenging cleans we used to face were the pubs where no maintenance on the carpets had been carried out for years. Over the years the carpet had absorbed all the food and drinks spills and then when it couldn’t absorb any more the dreaded black top appeared on the surface of the carpet. In the severe cases this black top increased in depth as more and more layers of drink spills and beer sugars formed.

After applying our cleaning agents to the carpet followed by agitation, we would break up the soil encapsulating it with the cleaning fluid and suspend it in the fibre. So far so good, but it was the next part of the process that I became frustrated with. We would then using our wand go to extract the cleaning fluid and suspended soil out with a stabilising rinse agent. We found that because of the absorbency of the heavy wool content we would sometimes have to make several passes with the wand over the same area before we had applied enough rinse to ensure all the cleaning agent and soil had been completely rinsed out. With the portables we were using we just couldn’t get enough flow and apply enough rinsing fluid into the carpet to rinse out in one pass.

The second part of our video explores what happens with pressure and flows when we increase and decrease jet sizes.

Reduced flow. We repeated the test and replaced the 2 x 03 jets with 2 x 02 jets.

After replacing the 2 x 03 jets in the wand with 2 x 02 jets, this has now reduced the potential flow through the wand jets by 33%. Due to the reduced and restricted flow the pumps will now reach pressure a lot quicker and the pump with no controls fitted should create greater back pressures whereas the digital system will adapt and adjust the flow and pressure to compensate for the jet changes. On the higher pressure pump the back pressure behind the jets may increase but there is little benefit because we now have a 1/3rd less flow potential through the smaller jets.

Increased flow. On the second part of our test we increased the flow by using 4 x 02 jets against the original 2 x 03 jets used in our first video.

We then went the other way and increased the potential flow by using a hard floor wand fitted with 4 x 02 jets which would equal the flow of 2 x 04 or 8 x 01 jets. During the previous test when no flow was available the higher pressure pump created 350psi back pressure behind the jet, when it was allowed to open flow unhindered it maximised its flow at 84psi through the 2 x 03 jets. With the high pressure pump already delivering its maximum flow through the 03 jets at 84psi, Increasing flow capacity further by increasing the jet size will not increase the performance of the pump delivery further.

As with all the other tests the EMVs digital system will not drop back pressure and lose flow performance because of the larger 4 x 02 jets. With the increased flow through the larger jets the digital control system on the EMV will adapt by adjusting the flow and pressure to compensate.

We designed our control system to balance and regulate flow with pressure to adapt with any changes in flow or pressure. The way we do this is with a true variable speed & pressure control system. The system monitors the pressure at the pump outlet and then regulates the pump speed and pressure to deliver the correct set pressure at the tool end. At the end of the part 2 video we demonstrate with the 4 x 02 jet wand and high flow that we can still increase the smaller pumps psi potential further.


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