Flexibility improves with mobile storage/retrieval

High operating speed, AC power and extended lifting height are critical to new efficiencies at Preferred Freezer Services.

Modern Materials Handling - October 2, 2006

When John Galiher, president of Preferred Freezer Services, looked for a storage/retrieval machine for his very narrow aisle (VNA) warehouses, the designs he found were not a perfect fit.

Preferred Freezer, a cold storage firm based in Jersey City, N.J., needed a storage/retrieval machine that could go down storage aisles in both directions and required minimal battery recharging and maintenance in cold conditions. And while he didn't find the right equipment initially, that has since changed.

Today at several of his warehouses, he has in place floor-running storage/retrieval machines move from aisle to aisle in the warehouses. The storage/retrieval machines also have high operating speeds and full weight capacity at all storage levels. In addition, the design is AC powered while in aisle, reducing the strain on and need to change and recharge batteries.

"With a counter-balanced hydraulic machine, the higher you lift the less weight you can lift, which reduces my storage flexibility," said Galiher. "AC units are more efficient. You don't use as much energy converting from AC to DC to battery and back to motor. Hydraulic units are compact, but they are not necessarily energy efficient."

The storage/retrieval machines receive power from conductor rails running along the top of each aisle. The units are fitted with twin power pick collectors so the equipment can operate in either direction and access all pallet locations.

Preferred Freezer also achieved a reduction in maintenance accompanied by the shift away from hydraulics. In the cold temperatures of the company's warehouses, hoses become brittle and crack, and hydraulic fluid often loses its viscosity.

"On these large machines when you get a hydraulic leak it is not like a forklift with two gallons of fluid," said Galiher. When you blow a hose 40 feet in the air they spray all over the place - on the product, on the forklifts and all over the floor."

The higher lift height of the lifts allowed Preferred Freezer to build taller facilities capable of storing more materials per square foot. In addition to lowering costs, the storage/retrieval machines' fully enclosed heated cabin has made it much more comfortable for operators to work long hours in temperatures as low as -18 degrees.

Since installing the first storage/retrieval machine four years ago, Preferred Freezer has continued to roll them out at other facilities, including three in 2006.