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Pirelli Explorer Maior

Discussion in 'Vintage Diving & Equipment' started by Joris Vd, Mar 14, 2021.

  1. Joris Vd

    Joris Vd Contributor

    # of Dives: 200 - 499
    Location: Belgium
    I was wondering if anyone had ever dived the Pirello Explorer two stage regulator with the weird bellow?

    I've looked for one for ages but have always missed out on the bid when there was one passing buy on ebay.

    The real question would also be: is it properly diveable? How is wob etc? And what do you guys think of the design of the reg, ingenious or borderline idiotic?


    Credit for the photo goes to the website cg-45.com
  2. axxel57

    axxel57 Solo Diver

    Interesting Design, but sorry, I don't know anything about that reg.....

    Attached Files:

  3. John C. Ratliff

    John C. Ratliff Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: Beaverton, Oregon
    I read many, many years ago that this Pirelli Explorer was used on a very deep dive (don't remember the depths, but well over 250 feet). Apparently, it allowed a slight rebreathing of the diver's last breath, which conserved air a bit. The duckbill valve being away from the diaphragm could cause some free-flow issues in certain positions. The reason for the bellows being on the chest and the short duckbill is to minimize the water pressure differential between the diaphragm and the outlet of the duckbill. If it was placed correctly, it would balance, but only in certain positions. I have never dived one. I think my LDS has one on display, and will look next time I go in.

    I have no idea of WOB, but I'm assuming that it was worse than single hose regulators, even tilt valve single hose regulators. But the fact that bellows were used means that the initial part of the inhalation would be nearly effortless (rebreathing part of the last breath), but then would kick in with harder breathing.

    Concerning the design, this was one of many attempts to overcome the Coustea-Gagnan patent on the exhaust of the Aqualung. By placing the exhaust away from the diaphragm/billows, there was no question that it did not violate the Cousteau-Gagnan patent in any respect. Take a look at these patents:

    The first ones are not apparently for underwater breathing apparatus.
    Google Patents

    US3348538A - Breathing apparatus exhalation valve with suction control - Google Patents

    US3348538A - Breathing apparatus exhalation valve with suction control - Google Patents

    This one apparently is the basis for the Pirelli apparatus:
    US3085571A - Underwater respiration apparatus - Google Patents

    axxel57 likes this.
  4. Mike Lev

    Mike Lev Contributor

    I have one. Have never tried it. Maybe this summer in the pool. They go for good money.

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