Can someone please educate me on what the mechanical/physical/operational differences are between an inspirator and an injector?

Thanks, -Jason

I pondered this many years ago when I had daily exposure to an "inspirator". My research came to the following conclusion:

a) an injector has a single chamber with a combined suction and delivery nozzle that creates a vacuum and then discharges a jet of water at high velocity.

b) an inspirator has two chambers which are individually adjustable. One chamber with nozzle for suction, which feeds a second chamber with nozzle for discharge. The steam supply to each chamber is individually adjustable, although usually tied together on the same handle.

One of the claims of the Hancock Inspirator is that it delivers water at a higher temperature than an injector. I checked the feed water line in front of the cab of an engine with Hancock Inspirators (SVRy 19) with a temp gun and the temp leaving the inspirator was around 180-190. I remember doing the same at some point in front of an Ohio injector, but don't now recall for certain what I found though about 150 kinda seems right. Someone made the remark in 19's cab one day that cold water is delivered to the boiler. 180-190 is far from cold or ambient in any event.

True, but it's colder than 370-380 degrees (water at 180-200 psi in a boiler).

Howard P.
Former Fireman, CT

On #401 we have 2 Hancock inspirators & they work great. They seem a little harder to get started than a injector but once you get used to them it is no problem.

Dave H.

In my experience with the Hancock, the problem was the mechanical overflow valve. On the Sellers, the overflow either uses a check valve or relies on a gap and fluid flow principals. On the Hancock, the overflow is closed by a linkage to the handle, and it frequently closed before the inspirator had developed a good vacuum and flow. I had to be really sensitive with the handle to develop a good flow before completing the handle movement.

What Steven said!! I should have added that myself Once you get used to them & know the quirks they do pretty good .

Dave Huffman

Yes, to what the previous 2 folks have said. SVRy 19's inspirators have always taken finesse, which means a pause just at the right spot when pulling back the handle. It's been a couple years since I worked in the cab, but as I recall you could hear a little click click noise which was probably the check valve you mention closing. If you heard the subtle clicks you could pull the handle on back.