Feb 1, 2008 12:00 PM

TANK MATERIALS

The first piston trailers were developed to transport bulk grease and consisted of three fiberglass cylinders mounted on what is essentially a platform trailer frame. Each of the three tubes holds 2,000 gallons of product. Some of these trailers are still in service.

However, the newest piston tanks in the fleet were constructed of stainless steel to DOT407 code. They have a full opening, flanged front head. Typical capacity is 6,000 gallons, which enables a 46,000-lb payload for most of the cargoes handled in piston tanks.

The heart of the system is the patented piston assembly. The pneumatically driven piston has airtight seals and a floating design. Following George Berry's death, the seals — essentially large inflatable O-rings — were developed by Burr Watson, who then was a partner at CBW Transport with Tom Berry, George's son.

The seals can be made of different materials to meet the requirements of the various cargoes. The O-rings fit so snugly that liquids, as well as viscous commodities, can be transported in the trailers. Spring-loaded pins keep the piston aligned in the tank.

“This is a very versatile system that can handle virtually any viscous product in a wide range of applications,” says Anthony DeJohn, vice-president of Piston Tank Corporation.

While most of the demand for piston tanks is in North America, an international market also exists. The piston system has been installed in swap tanks in Europe and in ISO tank containers that serve customers in Asia. Even storage tanks have been fitted with the piston system.

One of the biggest changes for the piston tank came in the 1990s, when Berry and Watson parted ways. The Berry family owned a majority of the CBW Transport operation, and that included most of the physical assets and the patents covering the piston tank system.

Watson received a five-year agreement that allowed him to use one of the original piston tank patents. It also gave him the right to market the piston tank for foodgrade and hazardous waste applications. At the same time, Tom Berry received a patent for a much-improved foam seal, which eliminated unexpected failures that often occurred with the inflatable seal.

PURCHASE OF CBW ASSETS

Four years later, Tom Berry contacted Schilli Corporation to see if there was an interest in leasing the piston tanks that were in the CBW Transport operation. In 2000, Schilli Corporation purchased all of the assets of CBW Transport, including the piston tank patents.

Then in early 2007, the Watsons sold all of their piston tank assets — including patents — to Schilli Corporation. All of these assets have been combined in Schilli Corporation's newly launched subsidiary — Piston Tank Corporation.

In all, Piston Tank Corporation controls a fleet of approximately 70 piston tank trailers in North America. Another 16 piston tanks are serving customers in Europe and Asia.

Piston Tank Corporation leases the tanks to its customers. The company also can provide transportation for the piston tanks through Schilli Corporation's tank truck carrier subsidiary — Truck Transport Inc.

“We believe leasing gives us the best means of serving our customers, most of whom are shippers,” Schilli says. “We can help them with all facets of managing the piston tank trailers. This approach also gives us the best opportunity to grow the piston tank business.”

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