Pointers to set up your wash plant for success this spring

Scott

The freeze-thaw cycle can do a number on washing and classifying equipment over the winter. A safe spring startup calls for operators to check several boxes on their to-do list ahead of production season.

One starting point is to conduct a visual inspection on all pieces of equipment, including conveyor belts and stackers, structures, interconnecting piping and electrical connections.

“Freezing conditions along with snow and ice can wreak havoc on hibernating plants that may result in cracked or ruptured pipes and valves,” says Michael Scott, process manager at Phoenix Process Equipment Co.

Scott, for one, suggests maintenance teams explore a number of items before bringing power back to a wash plant. Electrical connections and junction boxes should be inspected to ensure no breaks or cracks are present in PVC conduit or seal-tight fittings, he says. Additionally, structures should be examined for excessive rust once all snow and ice melts.

“All walkways, ladders, handrails and grating should be inspected and deemed safe for use,” Scott says.

Preparing pumps

Bennetts

Maintenance teams should also examine all belt-driven pieces of equipment, including pumps. Scott says pumps should have V-belts examined for condition and correct tensions.

“Belt safety guarding should also be checked at this time and repaired and replaced if necessary,” he says.

Alan Bennetts, global product manager at McLanahan Corp., agrees pumps require special attention as operators eye spring startup.

“Pumps have a distinctive issue because [of the] possibility of residual water being contained within,” Bennetts says. “During freezing temperatures, water increases its volume in the form of ice by about 9 percent under atmospheric pressure. Without room to expand, it will apply forces to the pump casing and may cause damage.”

If units have drain plugs, Bennetts says the solution to this potential problem is fairly easy.

“The removable plug allows for draining of the water while leaving the piping for the system in place,” he says. “In situations when a pump does not have a drain plug or the pump has been rotated for a different discharge orientation, then the best course of action is to crack open the casing.”

This is easier said than done, though.

“In order to crack open the casing, it is usually necessary to remove the suction piping and the discharge piping to allow enough of an opening to ensure complete draining,” Bennetts says. “I have been [asked] if antifreeze can be used to avoid cracking open the casing, but I have never recommended it – especially with rubber-lined pumps.”

While rubber has a level of chemical resistance, Bennetts says the possibility of chemicals attacking it when in contact for long periods can make a situation remarkably worse.

“Antifreeze is rated down to a specific temperature and Mother Nature does not read instructions,” he says. “Removing the water is the only way to ensure the destructive expansion does not occur when it freezes.”

Other considerations

Ahead of spring startup, Scott also recommends inspecting sizing and dewatering screens to ensure no panels are loose and that fastening pins are in place.

“The spray bars should be examined and inspected for freeze damage,” he says.

Additionally, all bearings should be greased to purge any moisture ahead of operation. Gear box oil levels should be checked, as well, and topped off with a manufacturer’s recommended oil.

“Following these simple post-winter startup inspections will get you moving in the right direction for a great production year,” Scott says.

Featured image: P&Q Staff