Introduction: Positive Pressure Suit (PAPR) From Inflatable Astronaut Costume
In light of the COVID19 pandemic, the Robots Everywhere team has been working to give makers new ways to improvise solutions and protect themselves.
This series of instructions will show you how it is easy to convert an inflatable astronaut costume (yes, this also works with the silly dinosaur suit) into a positive pressure suit (the full-body variant of a PAPR hood). The concept is relatively simple: upgrade the blower inflating the suit, turn it up, and the suit will not be able to hold air but also not explode. Because there is a constant positive pressure inside the suit, all air entering the suit (and breathed by the user) comes from the inflation pump's intake. Put a sufficient filter on this intake, and you are protected.
We demonstrated the same concept using painter's suits on our blog here. This is mostly the same project.
- Inflatable costume, such as the astronaut suit shown.
- Air bed pump or similar 12V inflation pump.
- HEPA filter or better. If you have N95 or N96 machine filters, please donate them to your local hospital if there is still a shortage. If supplies have been restored, feel free to use them!
- Scissors or a sharp knife
- A funnel
- Bungee cords, heavy duty elastic, or strong adhesive tape.
- A length of air hose, such as from a shop vac, or possibly included with the air pump.
- Small funnels or the adapters from an inflation pump kit such as the one recommended above.
- Glue that can create an airtight seal, such as gel super-glue, or epoxy. Ensure it works on the plastic material of the blower housing and your funnel.
- A 12V battery that you can carry with the suit.
- (Optional) Duct tape in case you run into any leaks in your hose assembly.
- (Optional) A mesh bag or something similar to carry your battery and pump in while wearing the suit.
Step 1: Prepare Intake Filter
Open the packaging for the pump and the HEPA filter. Mate the air out of the filter to the air intake of the pump - they should be roughly the same size. Hold them together by hooking your bungee cords into the top of the filter, and wrapping them around the base of the pump, as shown.
If you do not have bungee cords, you can do the same thing with rope or duct tape. Do not glue the filter in place, as it will need to be changed at some point, and this will make it very difficult!
Step 2: Remove Blower Assembly and Battery Box
If your suit has a battery, disconnect the blower from the battery box by unplugging the cord. Remove the blower assembly from the inside of the suit by unscrewing the ring on the outside. This should open the air intake hole in the suit and allow the blower to be removed.
If the battery box is detachable, remove it, carefully.
Step 3: Open Blower Assembly
Open up the blower assembly by removing the screws holding it together. Some suits may also have some glue assisting the screws holding the blower together - gently break the glue seal with your knife. You should now have two halves of the blower assembly.
Leave the half with the motor aside for another project - it is too weak for your application.
Step 4: Adapt Blower Housing to Air Hose
Using your glue, you now want to attach the funnel to the INSIDE of the blower assembly, on the side without the motor - this side will now be the intake. Glue it as shown. Make sure you use enough glue to create a tight seal. Gel based adhesives are excellent to fill gaps.
If there are leaks around the edge of the funnel, it will reduce the airflow into the suit. You can use your duct tape to close these leaks.
Step 5: Adapt Air Hose to Funnel
Take your air hose, and attach it to the stem of the funnel. If the hose is too large, you may need to cut the funnel and adapt the air hose to it. Use your glue and your duct tape to seal the hose to the funnel if necessary.
You may now connect the air hose to the new inflation pump that you added a filter to in step 1.
Step 6: Reattach Blower Assembly to Suit
Using the ring you removed in Step 1, reattach the blower to the suit. It should now have a hose extending from it as shown, going out to the inflation pump.
Step 7: Adapt Power Supply
Take one of the power cords from the inflation pump (they often come with a 12V car adapter as well as a wall adapter) and cut it from its original connector. Adapt this cord to your battery - you may need to solder for this step, depending on your choice of 12V power supply.
We do not recommend using 12V lead-acid batteries as they are heavy and unsafe to carry. 12V tool batteries may also pose problems, due to discharge protection being housed within the tool rather than the battery on most models.
RC car and aircraft batteries are excellent for this application.
Step 8: Pack Up
Put the pump, battery, and cords in the mesh bag, making sure the air filter for the pump is unobstructed. The bag strap can be worn with the suit, or attached to it. Depending on the suit, it may or may not be safe to use your duct tape here - nylon belts or rope may help carry your battery if it is heavy.
You can then deflate the suit and bunch it up if you need to move it around or store it.
Good job, you're done!
2 years ago
Really nice job putting this together :)