Valve Makes Resin Flow Child’s Play At Little Tikes

It is said that every dark cloud has a silver lining. The managers at Little Tikes Commercial Play Systems Inc., a rotational molder of playground sets, might agree. A fire four years ago at the company’s Farmington, mo, plant disrupted production, but provided an opportunity to upgrade the facility’s design and operation. In one area especially, materials-handling, Little Tikes revamped and improved its resin-coloring and -feeding system.

A key component of the system is the multiport Wye Line Diverter from Salina Vortex Corp., Salina, ks. This is a pneumatic valve assembly that channels pigmented polyethylene via plc-controlled sliding-blade diverter valves, from two sources to 12 silos on the plant floor for storage prior to molding.

“We were looking for ease of use and low maintenance. This diverter valve achieves that,” says William Rodgers, Little Tikes manufacturing engineer. Since its installation in 1998, Rodgers says that the MultiPort Diverter hasn’t yet required maintenance or cleaning, even though it conveys some 6 million lb of lldpe every year. (Rodgers was interviewed in late October.)

The valve assembly replaced a hose manifold station that required the manual switching and connection of flexible hoses to inlet and outlet pipes. The process was labor-intensive, open to error, and created the potential for product contamination, says Kevin Peterson, marketing manager at Salina Vortex. The hose manifold was also a potential safety hazard, since an improperly connected coupling could make a hose come loose under pneumatic pressure, creating the risk of injury as well as material spillage. According to Rodgers, there has been no contamination of resin or mechanical failure since the diverter valve assembly was installed.

The Wye Line Diverter comes in three basic configurations: 2-way, 3-way, and 4-way valves. The MultiPort in use at Little Tikes incorporates five Wye Line Diverter valves in different configurations — one 2-way valve; one 3-way valve; and three 4-way valves.

The resin-contact material for this assembly is aluminum. Salina Vortex can also supply contact metal in stainless steel or carbon steel, depending on application needs.

The plc regulates valve sequencing to determine where resin will flow. Little Tikes uses 23 pigments with the lldpe it rotomolds, though Rodgers says that less than half that number — generally 8 to 10 colors — are used on a regular basis.

Wye Line Diverter valves are lighter than cast iron versions. Con-ventional flapper-style diverter valves or rotating-tunnel diverter valves incorporate elastomeric seals, which can be eroded by material abrasion. The sliding orifice blade is designed to resist abrasion. It is also said to provide positive sealing in both vacuum and pressure-conveying applications.

One benefit of the installation at Little Tikes, which is a division of oem Newell Rubbermaid Co., is it freed up floor space occupied by the hose manifold station. Little Tykes and Salina Vortex did this by turning the support frame for the MultiPort Diverter upside down and installing the unit on the ceiling.

One factor that helped close the sale was a visit to Little Tikes by Salina Vortex’s local rep, Dynamic Bulk Systems of Fenton, mo, with the Salina Vortex Mobile Display Unit. This is a truck that contains samples of the company’s materials-handling products. Prospective buyers can walk through the displays, examine each, and get technical advice on the spot regarding installation and use.