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Post by yorkshireman on May 14, 2008 9:46:52 GMT
Would it be possible to operate a drive pump (under a tender, driven by a tender axle) also by a handle via some sort of clutch? Johannes
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Post by weldsol on May 14, 2008 14:45:10 GMT
I'm not sure if this wil work but here goes: one pump bore with central ports ( inlet clack & outlet clack valves) Two separate rams:one each end One driven by axle One powered by hand. You may have to latch a clamp on the hand lever when not in use as the pressure may push the hand lever ram back & forwards.
I thought about the clutch arrangement but could not get my head around to how it would operate
Paul
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Post by Tel on May 14, 2008 21:46:15 GMT
Is the tender going to have enough weight to drive an axle pump effectively?
If so, I'd approach it the other way - two rams in bores facing the same way in a common housing block. Two valve boxes at rear.
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Post by baggo on May 14, 2008 23:15:28 GMT
Tel's comment had occurred to me. Axle pumps take a lot of driving when pumping against boiler pressure and if there's insufficient adhesion on the tender wheels they may just lock up and slide along the rails.
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Post by ausdan on May 14, 2008 23:32:15 GMT
I always thought it could be an effective brake, have a by pass valve open for normal running, and decrease the flow to generate a braking affect ?
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ianmac
Part of the e-furniture
Posts: 308
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Post by ianmac on May 15, 2008 2:38:23 GMT
a "Jake Pump"
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Post by alanstepney on May 15, 2008 2:52:24 GMT
It might be possible, but I cant see any advantage.
If they both fed on to the same clack on the boiler, it would count as only one supply of water, thus to comply with the requirements for boiler feed, there would have to be a second (third?) feed pump elsewhere.
Other possible problems have been mentioned.
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Post by mutley on May 15, 2008 6:51:34 GMT
If they both fed on to the same clack on the boiler, it would count as only one supply of water, thus to comply with the requirements for boiler feed, there would have to be a second (third?) feed pump elsewhere. . Intresting comment Alan. I can see where you are coming from Ive just never seen the regs interpreted or applied in that way. Andy
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Post by yorkshireman on May 15, 2008 6:54:31 GMT
I see your point Alan, but I have also seen it very often, that the lines from a normal drive and hand pump do join at a T-piece close to a clack. Now, what is the exact wording in the 'independent feed' requirement? How far does 'independance' go? Inspectors seem to accept TWO pumps feeding to ONE common clack. Johannes
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on May 15, 2008 7:45:16 GMT
Don't ask the question guys!
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Post by mutley on May 15, 2008 9:28:16 GMT
Hi Tony I know what you mean. I find it intresting the way a 'standard set of guidelines' have been interpreted diffrently by so many diffrent people.
Andy
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Post by Shawki Shlemon on May 15, 2008 10:04:24 GMT
In OZ it is required to have minimum of two independent means of water supply of ones choice .
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Post by Laurie_B on May 15, 2008 10:35:17 GMT
In OZ it is required to have minimum of two independent means of water supply of ones choice . That,too is the case in the UK.At a recent steam test of my 5" BR Class 5 loco,our club boiler inspector tested two of the three means fitted to the loco for supplying the boiler-and was very interested to ascertain that the hand pump in the tender worked satisfactorily,rather than just testing both injectors. When I acquired the loco it only had two somewhat temperamental injectors,fed via steam valves that passed so much it was difficult to get water into the injectors! So,for peace of mind,I installed a commercially made hand pump in the tender,and,because the pump will deliver against full boiler pressure,I made the engine to tender connection using a commercially available 'high pressure connection kit'and plumbed the pipework into the 'bowl of spaghetti' pipework under the loco for which BR Standards are famous!I also modified the injectors steam valves so they don't pass,and fitted two No4 injectors that do work well. I'd agree that an axle driven pump under the tender wouldn't be such a good idea and such pump would best be driven from one of the loco's driving axles. For interest,below is pic of the retro-fitted hand pump.
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Post by ausdan on May 15, 2008 12:10:32 GMT
Laurie_B, is that vertical tube in you tender the over flow? If so I like that idea and will look at using it with my tender build
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Post by Laurie_B on May 15, 2008 12:45:54 GMT
Laurie_B, is that vertical tube in you tender the over flow? If so I like that idea and will look at using it with my tender build Ausdan-yes the vertical tube is indeed an overflow pipe.It does save an overflowing tank on club steaming days and saves soaking ones trousers in public-never a good idea!
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cotswold
Part of the e-furniture
Still testing the water
Posts: 307
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Post by cotswold on May 15, 2008 13:06:40 GMT
In OZ it is required to have minimum of two independent means of water supply of ones choice . The 2006 edition UK regulations states, " ... water feeding ... by at least two independent means (hand pump, injectors, mechanical pump, etc.)". A common sense interpretation of the UK regulations would seem to be that at least two feed pipes and two clack valves are required. So if feed water is supplied to one of those clacks by, say, both an axle pump and a hand pump, there remains a question to be answered concerning common mode failure at the clack. But there are still two clacks so the regulations are still satisfied.
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Post by heyfordian18 on May 15, 2008 19:12:49 GMT
Sounds like the interpretation regarding the number of clack valves is something to added to the agenda of the forthcoming seminars for boiler inspectors being run by the Northern Fed.
I don't like injectors that feed into clack valves fitted low on the backhead, at least not without an in-line clack in the delivery pipe as well. Nothing in the boiler code to prohibit it, but.....
I had a nasty experience with my 1400 when the backhead clack on the injector decided to go open circuit at full boiler pressure. It doesn't take long to empty the boiler through the injector and with all that steam about finding the grate pin is not easy!
Re-piped the injector now to use the top feed, and feel much happier.
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Post by alanstepney on May 15, 2008 21:21:10 GMT
Without delving into the rules, my own interpretation would be that there should be two methods of feeding, each entirely seprate into the boiler.
If both fed to the same clack, you dont have two methods of feeding water, as one part of the system, the clack, is common to both.
Once you add this disadvantage to the system originally suggested, I think that makes the idea impractical.
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ianmac
Part of the e-furniture
Posts: 308
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Post by ianmac on May 15, 2008 23:45:04 GMT
"I had a nasty experience with my 1400 when the backhead clack on the injector decided to go open circuit at full boiler pressure. It doesn't take long to empty the boiler through the injector and with all that steam about finding the grate pin is not easy!
Re-piped the injector now to use the top feed, and feel much happier. "
I cant beleive that they allow that in the code!
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Post by Boadicea on May 16, 2008 7:46:02 GMT
1)Without delving into the rules, my own interpretation would be that there should be two methods of feeding, each entirely seprate into the boiler. 2)If both fed to the same clack, you dont have two methods of feeding water, as one part of the system, the clack, is common to both. 3) Once you add this disadvantage to the system originally suggested, I think that makes the idea impractical. Alan, very much agree with points 1 and 2, and nearly agree on point 3. The regulation says "THE OPERATION OF INJECTORS AND FEED PUMPS SHOULD BE CHECKED AND IT SHOULD BE ESTABLISHED THAT THERE IS AN ADEQUATE METHOD OF FILLING THE BOILER, WHEN IN STEAM, BY AT LEAST TWO INDEPENDENT MEANS." Allowing for the appalling English (for the whole document), "two independent means" can only indicate feeding at least 2 separate clacks - no room for interpretation. In point 3, if an injector was added into a separate clack, then the other two could share a clack, be within the regulations and be safe. However, I think it is even safer, and a much nicer engineering solution, to have 3 clacks and keep them entirely separate. Clack problems are common and if you have 3 and lose one you MAY still have 2 other options. A pessimist would then say if you have 3 there is more chance of one going wrong! Hey Ho!!
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