Toasters repurposed for PPE in fight against COVID-19

Story by David Tenenbaum —

A University of Wisconsin–Madison alumnus is converting toasters into a conveyor-belt device that may be capable of sterilizing up to 150 face masks per hour using ultraviolet light so they can be reused. The intent is to aid frontline medical workers responding to COVID-19 by helping to alleviate shortages of personal protective equipment.

Bruce Winkler, founder of Innovation Strategies, LLC, is overseeing development of the new sterilizers and is offering one unit free to frontline health care facilities treating COVID-19 patients.

Ultraviolet light is the invisible part of sunlight that causes sunburns. The sterilizers contain 48 light-emitting diodes and mercury vapor lamps that emit a high-intensity form of UV light called UV-C, which sterilizes by destroying the genetic molecules DNA and RNA.

Face masks are sterilized with UV-C light in a device made from a toaster

Bathed by ultraviolet light from 48 sources, these face masks are sterilized in six seconds. Photo: Innovation Strategies, LLC

The virus that causes COVID-19 is new to science and few studies have validated its response to UV-C sterilization. But Winkler says there are many reasons to expect it to work, including recent evidence from the University of Nebraska, which is using ultraviolet germicidal irradiation to sterilize N95 respirators in health care settings.

Additionally, the International Ultraviolet Association recently said it believes that “UV disinfection technologies can play a role in a multiple barrier approach to reducing the transmission of the virus causing COVID-19, SARS-CoV-2, based on current disinfection data and empirical evidence.”

The exposure in Winkler’s system is calculated — based on UV-C intensity, duration, and proximity to the masks — to kill more than 99.99 percent of pathogens during a six-second exposure. “Studies have shown that UV-C can be used against other coronaviruses, such as SARS, and a concentrated form of UV-C is now on the front line in the fight against COVID-19,” Winkler says. “In China, whole buses are being lit up by the ghostly blue light each night, while squat, UV-C-emitting robots have been cleaning floors in hospitals.”

Winkler has been developing UV-C products to kill viruses and bacteria in medical settings for 10 years.

“These light sources were intended for use in hospitals and clinics, and that experience made for a natural pivot to assist in the pandemic,” he says. “It’s hard to argue that re-using a mask for an entire week, or having no mask at all, is preferable to using one that has undergone intense UV-C cleansing or sterilization treatment.”

The heart of the sterilizer reflects a shotgun wedding of two unrelated products: a conveyor system from commercial toasters used in hotels, and the UV-C light sources.

A person clad in protective gear feeds a face mask into a prototype sterilizer

The conveyor-sterilizer places the familiar hotel toaster in a whole new light. Here, during tests, a protected operator feeds masks into a prototype. Photo: Innovation Strategies, LLC

“Putting these existing components together cut months out of the development process,” Winkler says.

An operator, clad in personal protective equipment and wearing UV-blocking goggles, feeds masks into the system, one by one, at a rate of 150 per hour. Other objects, such as gloves, keyboards and computer mice could also fit inside the converted toaster.

A person stands in a sterilization chamber during tests using UV-C light on personal protective equipment

In a system under development at Innovation Strategies, UV-C light is used to sterilize protective gowns and other larger PPE components. Photo: Innovation Strategies, LLC

Winkler is also working on a system to decontaminate protective gowns, using similar UV-C technology, inside a purpose-built tent.

Despite the high intensity of the UV light, the system uses far less electricity than a regular toaster, and the masks warms only slightly. In contrast, the heat of standard autoclave sterilizers would destroy masks.

Winkler, founder of Innovation Strategies, received a bachelor’s in mechanical engineering from UW-Madison in 1983. Since then, he has invented, designed and developed products and equipment for an international clientele, ranging from scientific and medical devices to entertainment systems and consumer products. He has particularly emphasized lighting, both for artistic and industrial purposes.

As COVID-19 became pandemic, Winkler saw his expertise as a natural fit for medical needs. “Small businesses can do extremely quick development turn-around on an idea like this – going from concept to plan to implementation and testing in weeks instead of years.”

Virtual teams work best to meet this type of urgent need, Winkler adds. Assembly will start this week at Electronic Theatre Controls, in Middleton, Wisconsin.

Based on industry connections, Winkler recruited component suppliers to provide key parts at no cost. These include Clark and Associates, which supplies the commercial toaster conveyor units; BOLB, which contributes the UV-C LED arrays specific to medical and sterilization applications; W.L. Gore and Associates, which supplies advanced reflective materials to optimize the UV-C optics; and Germbot, LLC, which provides UV-C lamps, expertise and project funding.

Though he will ultimately offer the devices at cost, “we all know that time is pressing. You don’t want to reinvent the wheel. It makes more sense to re-purpose what already exists. And the price — $0 – is right.”