I have some questions about pre-oil hydraulic (Oildraulic) elevators (note that I am not an elevator technician, I am an elevator enthusiast wanting to learn more about historic elevators).
1. Did Rotary invent the Oildraulic elevator in 1937? Or was it a different year?
2. Before Rotary invented the Oildraulic elevator, were there water hydraulic elevators that basically worked almost exactly the same as an Oildraulic elevator, but with water instead of oil? (I ask because I saw a freight elevator that had a nameplate that appeared to say 1931 as year installed, and it was a hydraulic elevator, and as far as I can tell it has always been hydraulic, there are no signs I can see that it used to be a traction elevator).
3. Before pump hydraulic elevators, did there use to be hydraulic elevators that simply worked on city water pressure to go up instead of a pump, and that dumped water into the sewer when going down (and could some of them not need electricity at all)?
4. I have heard of water hydraulic elevators that went 500 fpm or more. Are these elevators that run on only city water pressure?
5. Are there some water hydraulic elevators that are similar to what I describe in question no. 3, but do use a pump to go up, but don't have a holding tank for the water (the water goes into the sewer)? Because I recently got shown the machine room of a water hydraulic elevator, and it appeared that there was a pump, but I was told the elevator dumped water into the sewer (though the elevator is no longer in service). That elevator also had a device in the machine room that I don't know the purpose of (there was a cable going over it, was the elevator once operated by pulling a rope? I was told it was car switch operated before the elevator was taken out of service).
