Loading ...
Sorry, an error occurred while loading the content.

Re: Interesting steam engine

Expand Messages
  • grantfair2001
    I tend to like novel things in a somewhat knee-jerk fashion, which explains my interest in the thing. OTOH I also can step back and consider issues critically.
    Message 1 of 10 , Jul 31, 2009
    • 0 Attachment
      I tend to like novel things in a somewhat knee-jerk fashion, which explains my interest in the thing.

      OTOH I also can step back and consider issues critically.

      I really know nothing about steam engines, and I appreciate your post since it seems, as far as I can tell, to raise many interesting issues and questions. Mr' Greens failure to respond to questions speaks volumes, I guess, about its shortcomings.

      Finally, a good, well informed and articulate rant is joy to behold!

      Grant

      --- In multimachine@yahoogroups.com, Ian Newman <ian_new@...> wrote:
      >
      > Hi,
      >
      > OK - this may be a bit of a rant but I need to voice my opinion about Mr Green's engine.
      >
      > References to this steam engine come up from time to time in various groups and forums.  Below is a copy of my own views on the design which I posted on another discussion board:
      >
      > I've
      > visited Mr Green's website a number of times, and each time I notice
      > more errors and misleading statements and it is clear that the designer
      > has some rather misguided ideas and a poor understanding of both
      > mechanics and basic steam-engine concepts. 
      >
      > In the website the
      > designer makes a number of unsubstantiated claims that are worded in a way that seems to be deliberately misleading:
      >
      > 1) He claims that
      > the engine will run on a couple of PSI with low steam consumption ("low volume" to quote the site) but you cannot change the laws of physics or
      > thermodynamics - the available output power at the shaft will be very
      > small and the motor will not be able to do any useful work under these conditions.
      >
      > 2) He talks about "efficiency" without defining
      > how it is measured, and makes illogical statements such as "The output
      > shaft continues rotation while the pistons stand still. The result is
      > that the efficiency is increased dramatically." - I am lost for
      > words......
      >
      > 3)
      > He claims the design "eliminates the crank" yet the animated gif
      > clearly shows that the flex rod connects to an off-set pin (a crank) on
      > the flywheel.
      >
      > 4) He claims the design "eliminates side force"
      > but the cylinders oscillate (and so are subject to side forces) and at
      > the base of each cylinder there is a bearing tube to prevent the side forces twisting the pistons out of alignment within the cylinders (the equivalent of a crosshead in a normal engine).
      >
      > 5) He claims the
      > design is a great step forward because it does away with the lower cylinder glands and seals (in other words it has single acting rather
      > than double acting cylinders) as if this is a new concept.
      >
      > 6) He claims the advantages of
      > low maintenance - but ignores the boiler maintenance required.
      >
      > 7) He lists benefits of:
      > - Costs little to build,
      > - Extremely lightweight,
      > - Very small profile for economy of space.
      > All of which ignore the requirement for a boiler - note the picture of the engine installed in a  boat.
      >
      > 8
      > )  He states "The flex rod is nearly frictionless as the flexing is
      > like a spring in which the energy required to flex it is returned in
      > equal amounts." but if you look at the operation of the unit, one end
      > of the flex rod is at a fixed point on the frame on the axis of the
      > output shaft and the other on the (non-existant) crank - a fixed radial
      > displacement from the axis of the output shaft. In other words the rod
      > does not oscillate and bend from side to side, but twists maintaining a
      > fixed curve. There is no "spring action" involved at all.
      >
      > It just goes on and on.
      >
      >
      > For me, two of the most worrying issues are:
      >
      > He
      > dismisses problems of steam generation with the statement that "the
      > boiler requirements are minimal". (If he applies the same level of
      > engineering theory to his boiler design and construction as he shows in
      > the rest of his website, I would imagine that most members of this
      > group would take care to stay as far away from any of Mr Green's
      > boilers as possible.)
      >
      > Second, he claims that:
      >
      > "The
      > unique feature of the "Flex Rod Transmission" is that it produces an
      > intermittent movement whereby the valve movement is stopped in its open
      > and closed position during the power and exhaust strokes. This gives
      > prolonged, fully opened valve timing."
      >
      > Most steam engine designs
      > go to great lengths to REDUCE the valve open times (through the use of
      > variable "cut-off") to get maximum energy from the steam expansion - it
      > seems the designer of this device does not understand this rather basic
      > concept.
      >
      > This sort of poor presentation of ideas and design
      > gives engineering a bad name.
      >
      > Finally,
      > the design has been patented for six years, but Mr Green does not give
      > any instances of satisfied commercial users on his website.......
      >
      > Ian.
      >
      >
      >
      > --- On Tue, 28/7/09, grantfair2001 <grant.fair@...> wrote:
      >
      > From: grantfair2001 <grant.fair@...>
      > Subject: [multimachine] Interesting steam engine
      > To: multimachine@yahoogroups.com
      > Date: Tuesday, 28 July, 2009, 7:07 AM
      >
      >
      >
      >
      >
      >
      >  
      >
      >
      >
      >
      >
      > www.greensteamengin e
      >
      >
      >
      > The inventor says it will run on low pressure steam, which can be produced in a pressure cooker, and it can produce lots of power (several horsepower). It looks like a possible candidate for solar powered steam.
      >
      >
      >
      > I understand it is legal to make one patented device for non-commercial, personal use.
      >
      >
      >
      > The only major wear on this is on the o-rings. How costly are those?
      >
      >
      >
      > Grant
      >
    Your message has been successfully submitted and would be delivered to recipients shortly.