Scott C420 Powered Air-Purifying Respirator (PAPR)

© Brooke Clarke 2015
Scott C420 Powered
          Air-Purifying Respirator (PAPR)

Background
Description
    Photos
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Background 

The data sheet only says that is uses the BA-5800 battery or a Ni-MH version with only a Scott p/n.
Got this to see if the 5800BA battery adapter will work. 
 Note:  I only got the blower, not the face mask, hose or dual filters.

From: The Use and Effectiveness of Powered Air Purifying Respirators in Health Care: Workshop Summary, 978-0-309-31595-1 "Under Cal/OSHA regulations, PAPRs are specified for high-hazard procedures because they can offer assigned protection factors (APFs)4 ranging from 25 to 1,000, which reduce the risk more than the protection factors provided by N95 respirators.5 The improved protection is largely provided by the positive pressure in the head covering or facepiece. PAPRs with loose-fitting hoods provide additional potential advantages in that they do not need to be fit tested and they can be used by health care workers for whom an acceptable seal cannot be achieved due to facial hair or other factors. The hoods of PAPRs can provide splash protection and some degree of eye protection, and some workers have reported that the airflow can keep the shield from fogging and can reduce heat buildup. In the agency’s experience, there have been fewer equipment shortages for PAPRs than for disposable N95 respirators.

The most common concern Cal/OSHA receives regarding the use of PAPRs has been their effect on the sterile field, such as during surgery, as PAPRs do not filter the discharged air. Some health care facilities have tried using surgical masks under the loose-fitting head coverings or placing the ends of the PAPR hood under the surgical gown, but neither is a tested or certified configuration."

Wearing a W.W.II vintage gas mask for any length of time is extremely uncomfortable.  They are what's called "close fitting" in order to get a good seal and since you need to create a vacuum inside the mask when inhaling if there's any leak in the seal you will pull in the unfiltered air, a bad thing to do.  But with a PAPR the air inside the mask is under positive pressure and hence a small leak presents no problem.

Description

I've read that the blower provides 4 CFM, or 113.3 lpm at the mask.

In has two inputs for standard 40mm filter cartridges.  The threads on the battery compartment, the smooth cap and the air outlet all appear to be the same 40mm thread.

Battery Capacity

When running at 6.0 volts the motor requires 1.6 amps DC.  That's 9.6 Watts.  The BA-5800 is advertized at 10 hours of use, implying the battery has 96 Watt hours capacity.

This is in conflict with my data on the BA-5800 which says it's more like 44 Wh, i.e. about half the advertized run time.  Tell me your experience.

The EverReady Energizer E91 data sheet says the capacity of one cell at 1 Amp load (about half of the total load) is 1.5 Amp hours.
8 AA batteries would provide 8 * 1.5 Ah * 1.2 V = 14.4 Watt hours, or about 1.5 hours run time.

The EverReady Energizer L91 data sheet says the run time of one cell at 1 Amp load is about 3 hours, much better than the E91.  These cells also have a big advantage when it's cold.
Note the L91 has a maximum current specification of 3 Amps and the E91 has no maximum current specification.

    Photos

To Open:
Remove the battery cap.
Remove the center plug from the smooth cap opposite the batterey cap and remove the center screw.
Remove the 6 plugs (next to the 6 brass threaded inserts and remove the 6 screws.
Note when prying the two clam shells apart that the rubber sealing gasket surrounds the both ends of the battery tube so fold it over so as not be break.
Note all the screws were installed with a dab of white silicon rubber to hermetically seal them.  This needs to be repeated upon reassembly if the blower is going to be used for a real application where a leak would not be good.  Although a leak would let clean pressurized air out, not let outside air in.
Fig 1
Scott
                      C420 Powered Air-Purifying Respirator (PAPR)
Fig 2
Scott
                      C420 Powered Air-Purifying Respirator (PAPR)
Fig 3
Scott
                      C420 Powered Air-Purifying Respirator (PAPR)
Fig 4  Double loop of dental floss & Square Knot (Wiki)
The problem is the floss gets tangled in the cap spring.
Maybe tape floss to battery adapter?
Scott
                      C420 Powered Air-Purifying Respirator (PAPR)



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5800BA Battery Adapter

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Page created 26 March 2015