Water Pressure Affects Chemical Dilution Accuracy

Part two of this three-part article focuses on the affects of water pressure on dilution accuracy.

Changes in water pressure can be detrimental to the dilution accuracy of chemical proportioners. When water pressure increases, more water flows through a dilution control system. With higher water pressures, the flow of water through the dispenser also exceeds the ability of the unit to draw the appropriate amount of chemical into the water stream, resulting in improperly diluted chemicals, according to manufacturers.

“Typically, if water pressure is low, the dispensed solution will have too much chemical,” says Cook. “If water pressure is high, the dispensed solution will have too much water.”

Distributors can help facilities determine if they have fluctuating water pressure in their facility by using a water-pressure gauge at the proposed outlet connecting to the chemical dispensing equipment. By testing a facility’s water pressure, distributors can determine if a facility is in need of a newer proportioner that handles fluctuation. This only provides a snapshot in time, however, and can’t account for water pressure fluctuations throughout the day.

“More complex dynamic water pressure gauges are available, but ultimately the best safeguard is to install a dispenser with a wide water-pressure input range that can also provide accurate dilutions across that range,” says Cook.

Most chemical dispensers have a specified water-pressure input range, for example 20 to 90 pounds per square inch (PSI). If water pressure is outside of this range, the dispenser will likely not dilute the chemical properly.

“Proportioners are generally designed to reach their maximum performance at 40 PSI,” says Matt Hayas, global product manager for Hydro Systems Company, Cincinnati. “When pressures increase above 40 PSI, water flow also increases but chemical draw stays the same. This results in solutions ‘leaning out’ when the water pressure goes above 40 PSI.”

This over-dilution is a concern for end users since improperly diluted chemicals do not provide the appropriate cleaning efficacy, which causes cleaning staffs to fall short of standards, says Brass Clarkson, marketing communications and product development manager for DEMA Engineering Company, St. Louis.

Many newer dispensers already have pressure-regulation technology that eliminates dilution variance by controlling the amount of water allowed into the unit itself, never allowing the system to “lean out,” or over-dilute, the desired dilution target.

“External pressure regulators have been around for many years and simply reduce the pressure of the incoming water so that it can be set to 40 PSI,” says Hayas. “The disadvantages of this solution is that it can be expensive and you also introduce additional leak points.”

With flow washers, which have also existed for some time, as the water pressure increases, the washers flex and reduce the water inlet opening to restrict water flow. This keeps the dilution ratio more consistent. The “flex” of flow washers, however, can vary from one unit to the next. They also don’t pair well with low-flow, or bottle-fill, applications, says Hayas.

The latest technology, however, introduces a water pressure regulator right into the water valve. It works similar to an external regulator, but it’s inexpensive and doesn’t introduce additional leak points, manufacturers say.

Benefits Of New Proportioners

End users care about safety, sustainability, appearance, productivity and cost. An accurate dilution system can satisfy all of these needs.
“End users are constantly under pressure to reduce spending, and an accurate system can provide predictable chemical costs while also reducing their labor costs,” says Cook.

Several problems can occur if a chemical is over-diluted.

“It can lead to wasted labor effort, because a user may need to spend more time cleaning or recleaning an area; it can lead to tampering, whereby end users try to add more concentrate to the use solution; and disinfectants may not be effective in meeting kill claims, leading to HAIs and outbreak risks,” says Cook.

Meanwhile, if a chemical is under-diluted (too much chemical), it not only increases a facility’s costs due to wasted chemical, but it can also cause costly surface damage and sticky surfaces, and it can expose building occupants and cleaning workers to unnecessary safety hazards.

In addition, for facilities that require the use of sanitizers and disinfectants, a chemical dilution fluctuation could result in noncompliance with health departments and other regulatory body mandates.

Manufacturers of these new proportioners say properly diluted chemicals work the way they are designed to work, meaning no more poor performance because the diluted solution was too weak to do the job. If weak solutions are used to clean, more labor is needed in order to reach the desired level of cleanliness.

Distributors can provide real value to customers when they present a chemical dilution system that keeps their facilities looking great while controlling costs, reducing worker safety risks and improving their sustainability profile.