Power sprayer diaphragm pump and centrifugal pump

There are a number of steps you and your staff can take to get better results from your power spray rig pump, whether it is a diaphragm pump or centrifugal pump. These simple steps, if followed, can:

• Improve power sprayer pump performance,
• Reduce pump down time, and
• Extend pump life.

Pump Selection

Selecting the correct diaphragm pump or centrifugal pump for your application is critical. Not every pump can be used for every job. Pump selection should be based upon:

Desired Pressure & Volume – Higher volume pumps may be required for applications such termite pretreats.  Higher pressure pumps may be required to reach heights, push material through long hoses or throw material over some distance.  Generally speaking, higher volume and pressure requires a pump that costs more.  Diaphragm pumps and roller pumps can supply volume and pressure.  Centrifugal pumps can provide volume but not much pressure, so if you need a long spray hose to reach large properties, centrifugal pumps may not be the best choice.  You can find pump specs for many pumps at spray_pumps_and_parts.

Budget – Obviously your budget is a limiting factor.  Generally speaking, diaphragm pumps cost more to purchase than other types of pumps.   Some pumps require larger and more costly engines for power.  Be sure to calculate productivity impacts when selecting a pump.  For example, a larger pump that provides the volume and pressure to do a job quickly may cost more initially, but pay for itself through improved applicator productivity.

Staff Skill – Some pumps require a little more TLC than others.  For example, in our experience, Gear Pumps are cost effective and reliable when properly run and maintained.  However the pumps require periodic adjustment in the field.  We have seen many times when technicians have over-tightened packing nuts which can burn up the pump.  Similarly, when roller pumps start dripping, they should be serviced promptly before serious damage is done.

Material to be applied – Generally speaking, wettable powders (as well as herbicides and many fertilizers) are abrasive and corrosive on pumps than liquid pesticides.  The best pumps for these applications are usually diaphragm pumps, which can handle the abrasive materials.  Liquid pesticides are usually not as tough on pumps and therefore can be applied with a wider variety of pumps (roller, gear, piston, centrifugal, diaphragm, etc.).

Good Filtration

Ensure that only water and chemical gets to your pump.  Foreign material should be filtered out to reduce the chance of pump damage.  A filter that is too coarse may allow debris to pass to the pump, causing damage.  A filter that is too fine may clog quickly and starve the pump.  Most pumps will sustain serious damage if not fed properly.  If your water is not debris-free, consider additional filtration.  Installation of a filter basket in the tank fillwell, a filter on the fill hose, or two filters (first a course then a fine strainer) before the  pump may be appropriate.  Clean filters regularly.

Good Agitation

Use of granular or non-soluble products requires good agitation both to ensure the proper ratios of product are applied and to keep the material from clogging lines and starving the pump.  The selection of jet versus mechanical agitation will be covered in future articles.  Please feel free to contact the author  (email: andrew@qspray.com) for more information.

Proper Plumbing

Ensure your equipment is plumbed properly according to manufacturer specifications.  Examples include:

• Proper input line size to feed pump,
• Direct and clear feed to pump (too many constrictions or turns on the input can place undue stress on pump)
• Proper return to tank (many pump manufacturers do not recommend jet agitation on the return line)
• Centrifugal pumps require a vent line return to prevent pump damage.

Keep Equipment Clean.

Clean your tank periodically to remove buildup and debris. Debris will clog lines and starve your pump. You may be surprised at what finds its way into your tank. In our customer’s tanks we have discovered: rocks, rope, trash and men’s underwear. Flush your system periodically with fresh water.

Run Your Equipment Moderately.

You can extend life by running your pump at a moderate speed necessary to complete the job.   In our experience, some applicators tend to run pumps at full speed to finish the job as quickly as possible.  Most pumps are not designed to run at maximum for extended periods. Refer to your pump owner’s manual or contact your equipment supplier for effective operating ranges.

Maintain Your Equipment

Don’t wait for the pump to fail.  Perform preventative maintenance to prevent problems and keep your pump running properly.  Consult your owner’s manual.  For rigorous users, we recommend rebuilding pumps annually.  For example, replace diaphragms, bearings, packing, etc., annually to prevent more costly repairs.

Train Your Staff

Ensure your staff knows the proper operating ranges for the pump.  Have them check filters and hoses.  Ensure they know how to identify problems.  For example, a roller pump may still function with leaking seals (pump will drip from weep holes)  However, if your staff is trained to check the pump, you can keep a seal repair from becoming a total rebuild or a new pump purchase.  Likewise, many pumps, if run dry, quickly become a total loss.  Tracking equipment problems by crew, individual or by shift may help identify training opportunities.

These simple ideas can help keep your equipment running, your staff productive and your boss happy.

More discussion on  diaphragm pump and other types of pumps

The author is owner of Quality Equipment and Spray, an Arizona-based company that designs, builds and services pest, termite and weed control spray rigs. Get lots more information at  www.qspray.com or email at andrew@qspray.com.