WFP Systems and efficient flow control

A tradesman needs a full tool kit! There is no 'right way' - only the right way on a per site/per route basis. There are sites where an on-demand system will work, whilst on others a different approach is needed.

The benefits of water fed pole systems have been widely recognised for many years - in particular the safety of the operator who can clean windows several storeys high from the ground. Across the world the water fed pole is a much used and trusted tool of the professional window cleaner.

Carrying the right equipment providing a full capability, plus know-how of when and where the right use of kit is important.  By detailing all the options that people have, we can see the why, where, what, when, and how each option could have it benefits: Doing this, in turn, identifies the alternate set-ups that have their own benefits. The Operator then is empowered to increase their efficiency, which reflects in higher hourly rates ( or a greater ability to compete) and is home to the family earlier ( or the pub) ... depending on your persuasions.

A range of systems are available, On-demand trolleys – Backpack – Mobile truck mounted - Traditional and others.

While the ability to connect to a local water supply and produce pure water on a site has advantages there will be occasions when it is necessary to carry the pure water to the site particularly on commercial and domestic building with no external water supply.

Q. Is a tank system with a means to regulate both the pump and flow part of the solution?

Where a tank system is preferable the requirement to pump the water to the brush head becomes a necessity using either a gas powered generator or battery powered pump. When working with a tank based system, water use and battery charge come into play as you want to be as productive as possible from the charge in the battery and the water carried.

Production of pure water requires reverse osmosis and de-ionizing systems, filters, resin and a range of equipment, so again making the most productive use of each tank can earn additional $$$.

At it, most basic what does our pure water professional require in a tank WFP system?

• A water tank
• Hose line
• Pole
• Pump
• Battery

You could think that is it? While this would provide the basis of your system, is it the most cost effective system?

1. In the system above the pump will operate at its maximum at all times, perhaps as much as a gallon a minute or 60 gallons an hour. The pump is also pulling the maximum amount of current (amps) from the battery. Based on a gallon a minute pump, this could be up to 8 amps an hour, draining the battery very quickly.

Add the mechanical pressure on the pump hose lines and connectors which are more likely to fail if constantly working at maximum output, and it is easy to see this is not cost effective.

Why and what then is the solution?

A pump regulator added to your system will improve productivity and reduce your costs, providing the potential for additional work from the same tank and battery charge.

Using a V11 pump controller allows you to produce the required flow to the glass more effciently. It is possible to reduce pump speed pump anp draw and pressure to give improved water volume more efficiently. Slowing the pump reduces the current draw from the battery to 2 – 4 amps meaning the charge in the battery lasts longer.

How is this possible? Well a hose has a maximum expansion point, If more water is forced into the hose than it can cope with the result is back pressure. In effect the hose now acts as a restriction working against the pump.

System Pressure - Do we need to work at maximum pressure the whole time?

Running the system at maximum places a very high strain on the pump motor, hose lines, connectors and pump pressure switch. A pump regulator greatly reduces the risk of the pump pressure switch burning out. A pump working at maximum pressure is under a high inductive load (stored energy). The user is relying on the pressure switch to stop the pump when the flow is stopped.

The pump pressure switch cuts in at maximum pressure with the motor under a high load (and high stored energy) thus causing arcing across the circuit which then burns out the pressure switch. Pump controls use PWM (pulse width modulation) to slow the pump motor and reduce this high inductive load when the water flow and pump are stopped.

At maximum pressure you will have a jet of water up to 15 feet from the brush head, The water is bouncing back off the glass on to you and the ground and it is not cleaning the glass. A controller allows you to reduce this pressure to exactly that required.

2. Efficiency

Another benefit of the controller also meant the user no longer needed to run at maximum flow the whole time. In effect, they could double the number of cleaning jobs per tank by simply reducing the pump speed by 50%. Not only is this more productive in terms of work, the amount of pure water needed is reduced.

Many confuse water flow and Pressure. It is not necessary to have high pressure to gain good flow. Equally Simply having fast water does not equate to a good finish and working faster. The ideal is to have the maximum volume from the minimum pressure for each job. Reducing the system pressure will extend the life of a pump, connectors, and hose lines.

By reducing the amount of water needed on a job the user also reduces how much pure water needs to be produced extending the life of DI resin and RO filters

Some advocate that very high flow allows you to clean faster? If you can clean an external French pane (cut-up) window in 19 seconds .. how much faster can you get by doubling your water flow? The bio-mechanics of the human effort limit the top end.

You still have the same area of glass to cover no matter how fast the flow is. There are other factors to take into account. Eg pump size- hose size – efficiency of the motor – pressure required.

There will be occasions where a fast flow is necessary.  Equally, there is a need to be able to regulate flow to suit the conditions and the job at hand, therefore giving the user flexibility is key. In short, use only the water you need at each job.

Q. Can you put a pump controller on a booster pump, or only on a 'Push' Pump?

Yes, a controller would regulate a DC booster pump.

Q. Can you set the pump controller for one operator or two? One Pump and Controller per Operator, or one shared?

A. In an ideal world, I would suggest one control per pole. Although it is possible for one control to operate two poles. The current 12V DC controllers are able to auto compensate to maintain flow.

Or

Put another way as the pole is extended higher pressure is required to maintain the flow set. The controller increases the pump speed to maintain the preset flow rate. If running one control and two poles, It would be necessary to calibrate to the longest pole. However if one user stops the flow the control shuts the pump down to both poles

Some setups run two pumps + two control from one battery which is probably the better way to work with a two-man team. In this case, an 110 AH or higher battery would be a good idea as two pumps draw twice the current

Q. one pump, one controller, two poles - one at 4 stories, one at 3 stories: 5PSI head of pressure difference at the glass - what is the most effective, simple and economical way to balance it? Longer small bore tube? Microvalve? Needle valve? Etc

A. The Controller will operate with 6mm and 8mm hose and micro ore. The controller needs to be calibrated to the longest pole, this is to allow the controller to see the maximum pressure required in the system to give the desired flow. The control is widely used with pumps of 100PSI so the 5PSI differential would be managed by the controller auto adjust feature. Auto adjusts simply means that the controller will alter the speed of the pump to maintain the flow rate you have set. As the pole is extended the pump speed will be increased, lower the pole and pump speed is reduced.

The units are very flexible as to the range of pumps, hose, and microbore they will work with. The pump pressures up the system in order to establish a flow. The controller needs to know what this pressure is. The amount of pressure required will in part depend on how fast the flow is or how far the pole is extended.

3. So why calibrate the controller to a pump?

What we are doing is telling the control what the maximum pressure the system normally operates at. To get a good flow at the brush head, the system is probably running between 40 - 70 PSI. So the control knows that the normal max level is 70 PSI. When a user stops the water flow the pump will attempt to push against the restriction increasing the pressure above 70 PSI the controller sees this sudden rise and stops the pump. This is what we refer to as DEAD END (DE).

During this DE (flow stopped period) the controller periodically retests the pressure at the pump. When the restriction is removed the pressure falls back below the 70PSI maximum and the controller restarts the pump at the preset flow. Hence the need with a two pole one control system to set the calibration to the longest pole which requires the greater pressure.

The control is designed to stop the pump before the pump pressure switch activates where the water flow has been stopped. A pump pressure switch may activate at 110PSI give or take (based on 100 PSI pump) as described earlier running the pump to these high levels can cause problems.

The downside of one controller operating two poles here is that if one user stops the flow the controller will stop the pump and stop flow to both poles. It is more difficult for the controller to auto adjust when running two hose lines from one pump.

For this reason, we recommend one pump and control per pole

Varies the pump speed,

Controls water flow rates, detects flow stopped and shuts off the pump,

Autotests for restored flow and restarts the pump

Displays battery voltage

Auto adjusts the pressure to compensate for extending the pole

Calibrates to each pump and system

Reduces system pressure

Reduces strain on the pump and connectors

Will work with any hose including 6mm and 4mm microbore hose

The Control is designed to work with a 12V DC 7amp pump 1.2 Gallon pump (5.2) LTR a minute. The maximum current rating for the control is 10amps. The control will operate with a 9V DC supply and a larger pump providing that the maximum current rating is not exceeded.

The control must be connected using the correct polarity to the battery RED = Positive BLACK = Negative (Brown and Blue connect to the pump). Also, fit the fuse in line on the RED cable between the battery and controller.

4. Displayed Messages:

DE Dead End the control has detected water flow has stopped.

CAL The current calibration setting of the control

Auto Cal, please see the following link. http://www.youtube.com/watch?v=9kKoskb7l7c&list=UL9kKoskb7l7c

PS Your control is designed to work with the pump pressure switch connected. PS is displayed if the pump pressure switch is activated. Overpressure in the system activates the pressure switch and the controller passes the information on.

Common causes of pressure switch activation

1. A restriction to the water flow, i.e. from a twisted hose.
2. Blocked or small water jets. (We recommended that the jets are no smaller than 2mm).
3. Grit or dirt trapped in the system.
4. Air trapped in the system.
5. Prolonged shut off of the water flow.

BAT The Control us fitted with a voltmeter and displays the current battery voltage. The Control will display BAT if voltage is 11v or less