Trend air shield fan speed?

[Nail]

Hi.

I’ve had a trend air shield kicking around for a while that didn’t have a charger for the battery pack(s).

I didn’t want to spend any money on it as I’m not sure if I would like it so I’ve just done a quick and dirty connection of a usb battery pack to run it.

I’m wondering if this is a comparable fan speed to the standard batteries.

Any thoughts?

Thanks!

 

[Sideways]

I'd roll the dice and say that your proper headset battery pack probably has two lithium cells in series, and maybe the same doubled up in parallel for more capacity.
I assume these are new enough not to use nicads or nimh batteries ?

This is based on what some other types of powered respirators use.

2 lithiums in series is a nominal 7.2v, so your fan MAY be running slow.
BUT
The professional PAPR respirators have electronic control and measure actual airflow. They increase the power to the fan to maintain airflow as the filters get loaded. That sort of means that what comes out of the battery and what is given to the fan can be very different.

I think you need someone with the trend to measure their battery voltage for you.

 

[Chief Sawdust Maker]

I use the similar Axminster version and that come with a very basic airflow meter which is recommended to be used at the start of each to establish if the filters need cleaning / changing.
Its very simple, basically a small clear box that sits on the air inlet in the mask and a flip is lifted by the air and indicates in the green or red zone
May be worth asking around or if there is a local turning club near you
Hope this helps

 

[Nail]

I use the similar Axminster version and that come with a very basic airflow meter which is recommended to be used at the start of each to establish if the filters need cleaning / changing.
Its very simple, basically a small clear box that sits on the air inlet in the mask and a flip is lifted by the air and indicates in the green or red zone
May be worth asking around or if there is a local turning club near you
Hope this helps

That’s a clever idea!

 

[Nail]

I'd roll the dice and say that your proper headset battery pack probably has two lithium cells in series, and maybe the same doubled up in parallel for more capacity.
I assume these are new enough not to use nicads or nimh batteries ?

This is based on what some other types of powered respirators use.

2 lithiums in series is a nominal 7.2v, so your fan MAY be running slow.
BUT
The professional PAPR respirators have electronic control and measure actual airflow. They increase the power to the fan to maintain airflow as the filters get loaded. That sort of means that what comes out of the battery and what is given to the fan can be very different.

I think you need someone with the trend to measure their battery voltage for you.

It’s not lithiums. The one pack I opened up is nimh but still hitting that 7.2v.

I liked the idea of convenience by switching to usb. The opening up to charge these packs doesn’t inspire confidence in the long term structural side of this mask.

 

[Nail]

I wonder if it running a bit slower particularly matters? The function is going to be to be certain that air is blowing out of the bottom of the mask so any dust doesn’t get in and no condensation? If it’s achieving that does it need to run at its top speed?