Radiation Shielded Bifold Door

The creativity of customers continues to be a driving force for many manufacturers. Take for example North Star Imaging, Inc., a Rogers, Minnesota manufacturer of industrial x-ray systems which are enclosed by a radiation shielding cabinet and access door and used by manufacturing firms in the aerospace, military, automotive, medical device, electronics, even the genetic seed industry and many more.

As more and more companies realize the benefits of X-ray inspection, the size of various products needing x-ray inspection continues to expand as well. And this often means bigger doors to access these larger component parts into the x-ray system of these companies. Bigger doors with a built-in lead radiation shield to be more specific.

For example, North Star Imaging had clients in Texas and Connecticut, both needing an extra large access door to their new NSI X-ray system. A 40' wide door to be exact. But a lead-filled door of this size potentially presents a lifting challenge. The Internet to the rescue!

"We first learned about Schweiss Doors on the Internet. Their web site is loaded with information," relates Lou Ortega, Director of Engineering, North Star Imaging, Inc. "We saw that Schweiss offered two choices, bifold or hydraulic. Bifold doors were new to us. But when we checked out the specs, the opening and closing mechanism, plus the fact that the bifold door essentially opens straight up, we could readily see the mechanical advantage of a shielded bi-fold door," said Ortega. (www.bifold.com)

As the name implies, a radiation-shielded door has to be precisely engineered to provide protection during x-ray procedures. Yet this door also has to meet specific specs at each installation location. As NSI engineers analyzed their challenges, a Schweiss bifold seemed to be a perfect answer.

Said Ortega, "To my knowledge this is the first time a door of this type has been used in a radiation shielded enclosure. I have been in the x-ray business for 17 years and can tell you that this door coupled with the radiation enclosure is a very impressive system"

The two units installed were both 40' wide and 9' high providing a 7' vertical clearance. The 'protective' lead liner was 1/8th inch diameter thick and weighed 5,000 pounds! Sandwiched with metal siding on both sides, total weight of these doors was 9,300 pounds. Schweiss provided a heftier framework plus equipped each door with 7 of their patented lift-strap units.

"The lift-strap mechanism is what makes this door so functional. A single-piece hydraulic with lead liner would simply be too heavy," explained Ortega. And because of safety considerations of a door this heavy, Schweiss constructed a special 'Dead Man' switch, which requires both hands of the door operator when opening and/or closing the door.

Rod Meyer, National X-Ray Sales Manager, North Star Imaging, said initial reactions to this unique concept of a leaded bifold door for radiation shielding has been very positive. "Clients have been very surprised by the looks of the door, the smoothness and quiet operation, and the overall functionality. They were impressed and recognized this as a great engineering feat."

Special customized doors are nothing new for Schweiss Mfg., a Minnesota firm with 34 years designing and building doors for clients around the world. Schweiss created the concept of 'Designer Doors' and works with architects and builders to provide either bifolds or 1-piece hydraulic units. "We truly do custom manufacture every door. We design and build around the customer's needs," said CEO Mike Schweiss.

"Because we had a customer doing x-ray inspections on a 38' long component metal product. we knew we needed a special door," related Meyer. "When our engineering team found the Schweiss bifold, they could see that this was a special door package that would be big enough, yet conveniently fit the closure space required for this particular x-ray facility. We decided to move forward with the Schweiss system. They responded efficiently and professionally. We now confidently look ahead to more markets with existing clients and potential clients throughout the world."

North Star Imagining, Inc. is the leading manufacturer of industrial X-ray systems in the USA. NSI also has clients in China, Singapore and other countries around the world. Industrial X-ray inspection has many uses; some applications consist of detecting even the most minute imperfection in a metal or weld. Other uses are taking internal measurements of a critical product to creating a 3D model for use in reverse engineering and much more.

Size of bifold apparently is not an issue, at least not for Schweiss. The biggest Schweiss bifold to date is a 130' wide x 36' tall monster door at a New Jersey based aviation company.