Wet seal technology for spray pumps

The area highlighted in green indicates the liquid lubricant that prevents the wet seal from running dry or being contaminated by chemicals.  The wet seal is now standard on all Pentair Hypro 9306 and 9303 pumps.  |  Hypro image

BRANDON — Wet seals, employed in aircraft and industry for decades, are finally finding their way into agricultural spray pumps built by Pentair Hypro.

The big benefit is in situations when the pump runs dry, Pentair fluid specialist Brian Henderson said during Manitoba Ag Days at the end of last month, where he debuted three new Hypro products.

“Once the pump runs dry enough times, the seal usually fails, and that can mean you’re sitting idle for a day or two in the middle of spraying season,” Henderson said.

He said some farmers get five to 10 years out of a seal before it needs replacing. Sometimes the plumbing in the sprayer contributes to seal failure. In other situations, when an operator changes chemicals, the trend is to purge the system better. That means the pumps run dry more often than they did previously.

“The other benefit of a wet seal is it helps prevent chemical bonding,” he said.

“Sometimes the two seal surfaces will stick together because of the chemical reaction. With a wet seal, those chemicals don’t contact the seal surfaces.

“The lubricant in the seal housing is similar to antifreeze. It’s a special formula we’ve developed to help lubricate the seal. You need to top it up once every 1,000 hours.”

The wet seal is available only on the 9306 and the 9303 pumps, which are the two most popular pumps. These two pumps have just undergone a total re-design, which now incorporates the new seals on every unit. The new design also has a more powerful hydraulic motor and bigger bearings for longer life. He said it’s not possible to retrofit an older pump, but the new design fits the same footprint, so replacement is easy.

The wet seal technology adds about US$600 to the purchase price of a pump, which Henderson said is a small price to pay if it avoids even one day of downtime. The new pumps sell for about $3,000.

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