Steam Box - Disinfector

Due to the ongoing pandemic, there has been a sever shortage of personal protective equipment. Due to this shortage, many healthcare workers are forced to reuse this vital equipment which not only compromises them but also the patients they are treating/testing. Thus, it is imperative that this equipment being reused is completely disinfected. There currently exist

The goal of my design is to provide medical facilities in critical need a way to properly and efficiently sanitize protective gear for reuse. My design is essentially a heavy duty steamer. Water is boiled through the use of a heating element to produce steam, which serves to heat any gear placed to disinfect. The guideline currently followed in laboratories to inactivate SARS-CoV-2 is to heat it at 56 degrees Celsius for 30 minutes.

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Supplies

Materials:

• Plastic Tote (Polypropylene)
• Heating Element (2000 Watts, 120 Volts)
• Silicone Sealant
• Extension Cord
• Chicken Wire/ Metal Rack
• Screws

Tools:

• Wire Cutters
• Wire Strippers
• Screwdriver
• Power Drill
• Utility Knife
• Tin Shears
• Pliers

Step 1: Electrical

Using tin snips, cut off the outlet part of the extension cord, leaving only the plug and the cord. Make sure you cut so that the cord is long enough for easy use.

Step 2: Electrical

Typical extension cords contain two wires, each individually coated in their own insulator (PVC, rubber, etc.). Using a utility knife, make a cut about two inches down the middle of the two wires (left picture), making sure to separate them (right picture).

Step 3: Electrical

Use a wire stripper to strip the copper wire inside from its rubber/plastic coating. Strip only the area that you separated in the previous step.

Step 4: Electrical - Heating Element

Next move onto the heating element. Note that at the bottom of the heating element there are two screws where wires connect to. Unscrew one of the screws and wrap one of the exposed copper wires from the extension cord around the screw (left). Making sure that the copper wire stays wrapped around the screw, screw the screw back into the socket (middle). Make sure that the copper wire is held in place tightly by the screw. Repeat for the second screw with the other copper wire. The end result should look like the picture on the right.

Step 5: Plastic Container

Next take your plastic container and cut a hole into the side, close to the bottom of the container. The diameter of the container depends on the heating element being used, make sure that it is a little bit smaller than the base of the heating element. Most boiler heating elements have a thread at the top of the base, we want the hole to be large enough for this threaded part to fit inside but small enough so that the gasket stays on the outside.

Step 6: Plastic Container

Around halfway up the container, screw in two screws on one side. Screw in two more on the opposite side. These screws will help hold up the rack where the items to be disinfected will rest.

Step 7: Rack

Cut chicken wire to size so that it fits inside the plastic container and can rest easily on the screws put in earlier. In this example I use racks that used to be part of a shelf, but you can substitute with anything that can serve as a rack.

Step 8: Assembly

Insert the heating element, making sure that the part with the thread is on the inside of the container. For most boiler heating elements, the rubber gasket is following the thread and will be bigger in diameter than the threaded part. The heating element should not go in further than the gasket. The electrical part of the heating element should be on the outside (rightmost picture).

Step 9: Assembly

Next, screw a PVC slip joint nut (or any nut large enough) onto the thread of the heating element. Make sure to tighten it firmly. This helps keep the heating element in place.

Step 10: Assembly

Apply sealant around the hole where the heating element is inserted on the outside of the container. Silicone sealant should work fine (picture shows epoxy). Before moving on, make sure that there is no leak by filling up the container with water. If there is a leak, empty the container and let it dry. Then apply sealant on the part where the leak was coming from and let the sealant dry.

Step 11: Usage

The steamer is now ready for use. All that is left to do is to fill the container with water, place your items on the rack, and plug it in. Make sure to close the top to prevent heat from being lost.

Important Notes:

By plugging it into an outlet, you are turning on the steamer. By unplugging it you are turning it off.

Make sure to fill the container with water to a point well above the heating element. The heating element will get damaged if it runs without any water.

The inside of the container will reach high temperatures. When opening to retrieve items, make sure that you unplug it and allow for it to cool down. Open it from the side so that your face is not directly above the container.