by Nick Dorsch, Versa-Matic Pump Company

Another diaphragm ruptures, and your customer needs this batch of latex yesterday to mix their new line of paints for the season’s hottest hues. What’s the solution?

When one major base latex paint manufacturer became frustrated with frequent pump stalls and downtime, managers knew they had to find a way to cut their mounting costs.

Like most other paint processing facilities, this manufacturer used air-operated double diaphragm (AODD) pumps in every processing zone. First, the pumps combined monomers in the soap tank and then transferred them to the reactor for heating. Next, the pumps moved the base latex to the chiller, then on to the filtering room and, finally, to storage tanks and totes.

Setbacks along the way caused a domino effect that impacted the entire process and delayed deliveries to customers who bought the base latex for use in their paints, coatings, wallpaper paste, and more. 

The AODD pump transferring chemicals to the reactor.

The pump transferring product from chilling tanks to bulk storage.

Pump failures were beginning to cause financial failures. Costly wear parts had to be replaced frequently. Significant downtime hurt the facility’s productivity and often caused the latex to dry mid-process, which ruined entire batches of product. Redundant work aggravated pump operators, and excessive overtime pay took its toll on the budget. That’s not all. Utility bills had skyrocketed because the inefficient pumps used large quantities of expensive compressed air.

Searching for solution to these problems, the manufacturer agreed to install an Elima-Matic® air valve on a trial basis. The valve proved so reliable that the manufacturer installed more – on 70 percent of its pumps. Eventually, the company replaced all 150 of its AODD pumps with models using this patented air distribution system. This resulted in a significant increase in productivity and a solid return on the investment. The time savings substantially improved efficiency, and still continues to lower the total cost of ownership today.

A cutaway image of the inside of the pump that eventually replaced all of the AODD models used in this latex paint manufacturing operation. 

Eliminating Those Pain Points

Before this base latex manufacturer implemented the air valve system, maintenance was a key pain point.

Throughout the facility, processors had to run a constant, costly, and messy stream of water across the old pumps to try to prevent freezing and stalling, but the pumps often failed anyway. Workers kept hammers close by at all times. In addition, whenever a diaphragm would rupture, cleaning and replacing up to seven O-rings with an O-ring pick was difficult because the center block bushing was so small and complex. Workers also could not determine if the O-rings had been positioned properly until the whole pump was reassembled. Repeat attempts often wasted valuable work time.

Installation of the air valve system greatly minimized maintenance issues. The pumps didn’t freeze or stall, and the individual parts lasted much longer than standard wear parts. The pumps also used much less compressed air, which significantly lowered the company’s utility bills.

Even now, when occasional repairs or part replacements are necessary due to regular wear, the simple pump design allows for fast teardown and repair. For example, workers can easily disassemble a pump to remove dried latex with a blowtorch, instead of having to replace an entire clogged bushing. Through low maintenance and efficient, reliable production, the pumps continue to deliver a solid return on the investment.

Perfect for Pumping Paint

Because binder comprises 30 percent of typical paint composition, pumps used in the paint industry have to be especially durable. The properties that make resins and drying oils successful as binders of pigments are the same properties that cause buildup inside processing equipment.

The binders in latex emulsions are polymerized from styrene, butadiene, vinyl acetate and acrylic monomers, and are extremely heat- and shear-sensitive, which makes pumping them a particular challenge. Latex viscosity can range from 100-SSU (20-cp) to 25,000-SSU (5,500-cp), and temperatures can reach up to 400-deg F when pumping synthetic resins. 

The initial chemical additives are mixed using these pumps.

A pump and filter unit used for pumping latex base.

These AODD pumps are designed to meet the specific needs of latex pumping facilities. They can handle a range of viscosities — from water to 90 percent solids — which is perfect for accommodating the varying quality of resins and paint slurry. Because the pumps can operate at varying speeds, they are ideal for the transfer of abrasive pigments and highly viscous paste through the paint processing stages of grinding, thinning, straining and packaging.

In spite of the harshness of the materials used in this industry, the parts and diaphragm technology are designed to wear more slowly than the components of competing systems.