I recently picked up an Ashton illuminated pressure gage. 14" diameter. The lighting fixture is missing but it looks like it won't be too difficult to put one in. I recently picked up an Ashton illuminated pressure gage. 14" diameter. The lighting fixture is missing but it looks like it won't be too difficult to put one in.
I also found a pocket size caisson gage used to measure air pressure. https://en.wikipedia.org/wiki/Caisson_(engineering)
That is really cool Rick. As you know, there was much that was not understood with worker illnesses when caissons were put to use in building bridge piers and tunnels. "Caisson Disease" was its common name, which we now know as "the bends". I think it's neat that such a pocket device was built to monitor atmospheric pressure. I'm assuming that it reads in inches of mercury? (29.9" is normal I think).
I believe it just reads the surrounding air pressure. I'm not 100% sure but there is no mention of mercury in the catalog descriptions.
I'm sorry, I didn't explain that very well. An "inch of mercury" is a common unit of measurement for atmospheric (air) pressure, i.e. what normally surrounds us. It's the standard that most U.S. barometers read. Mercury was used when the standard was created, but spring mechanisms have long since prevailed in most applications (as when the Ashton gauge was made) and mercury is not needed. Here where I am, it's 29.98 right now. I sent your caisson gauge pictures on to a friend who is a fan of such things and he greatly enjoyed seeing them. Thanks again.
it would have been visible in a boiler room under low light conditions. Here's a catalog page rom the 1920 catalog.
Here's the gage illuminated. I'm missing the piece that would have hidden the shadow of the Bourdon tube in the center of the gage. I might have to rig something up.
The ad above shows "Ashton Marine Pop Safety Valves". This has me curious. What would be so specific to "Marine"? As compared to a heating plant boiler or railroad engine?
Good question. I'm not 100% sure. I've attached a catalog page from the 1928 catalog and the safety valve is listed as being for stationary or marine use. I can only assume that maybe it was listed that way just to appeal more to the ship industry. The adverts were from SHIPBUILDING ENCYCLOPEDIA so they probably were tailoring the advert for that market.
Perhaps the marine version was more visually refined. That is done in manufacturing for different uses.
I always appreciate your posts Rick. Always neat stuff to see. In my career, I worked in heavy manufacturing and our plants were equipped with enormous water tube power boilers standing many stories high. The steam from these drove turbine power generators. Man, when those safety valves lifted, the whole place would shake and the noise was deafening. These were tested and calibrated several times each year.
Only that I bought the parts needed for preventative maintenance and hired the contractors to work on them. I went inside the boilers numerous times during our week-long maintenance outages. We stationed a 24x7 'Hole Watch' person at the entry port of each boiler so that everyone entering and exiting was accounted for at start up.