rambo Posted December 27, 2008 Share Posted December 27, 2008 Hi! All, I am having problems with my self fabricated 6.5 Tons Power Hammer running on steam. When the operator lifts the handle to take the ram up he is unable to control the handle as there is an external force on it to move up. There is tremendous load on his hand to keep the handle from going up and thereby the piston hitting the top of cylinder. I believe this has something to do with the design of the motion valve, can some body help me with this? Thanks Rambo Quote Link to comment Share on other sites More sharing options...
Shane Stegmeier Posted December 27, 2008 Share Posted December 27, 2008 It sounds like you have it designed to manually switch the flow from down to up, and the same force that is driving the 13,000# head up is finishing opening the valve for the hammer driver. You need a control circuit that allows the actuator arm to control how open the valve is but is not physically linked to the valve. Beyond that i am not much help... Hope this gives you enough info to look for the right answer. Quote Link to comment Share on other sites More sharing options...
ptree Posted December 27, 2008 Share Posted December 27, 2008 Rambo, I would offer that you need a safety cap for that hammer. If you are hotting the cylinder cap, it is only a matter of time till you fail the cap and have the cap come off and have a disaster. On the valve, without seeing it I would ask if the valve is not directly linked to the cylinder, then the valve needs to be a "balanced design". The steam pressure that is inside the valve needs to have balanced areas so that there is no force tending to move the valve element inside the valve body. I do not know what you actual valve internals look like but suspect that if the valve is tending to move fully once moved, yet the operator can over power that force that the internal pressure acting on the valve itself. Quote Link to comment Share on other sites More sharing options...
Bentiron1946 Posted December 28, 2008 Share Posted December 28, 2008 How about posting some pictures of this hammer of yours and the problem area in particular? If we can see the problem we may be better able to help. Quote Link to comment Share on other sites More sharing options...
rambo Posted December 30, 2008 Author Share Posted December 30, 2008 sure. i will post some pics in a day. thanks for the responses guys. Quote Link to comment Share on other sites More sharing options...
nonjic Posted December 30, 2008 Share Posted December 30, 2008 I assume a straight spool valve (expansion valve) of approx 10" diameter for this size of hammer. The valve, valve tube and valve chest design are all critical on this type of hammer. It sounds to me like you are getting back pressure on the valve (ie the live steam, or exhaust steam is pushing the control valve) Balancing these valves is not easy. On commerically made hammers you will notice drilled holes, chamfers and cut outs in the valve, these all help prevent localised pressure build ups in the valve and valve chest. (as well as 'feathering' the control of the hammer) You really need to discuss this with the engineer who designed (or copied the design) of the hammer. Without 'projecting' the valve & tube onto paper I am afraid it is very difficult to diagnose this type of control issue. I can do it, but this is much more of a project than you might think, and not somthing I would do pro-bono on a website I am afraid. As others have mentioned make sure you have a sturdy cable attached to the cylinder cover plate, I have seen these smashed off in the past, and Im guessing the diameter of your cylinder is 30", so a tidy sized cover! It is not to difficult to manfacture a live steam buffer to bolt onto the top of the existing cylinder, you should explore this route with your engineers. Quote Link to comment Share on other sites More sharing options...
element Posted December 30, 2008 Share Posted December 30, 2008 Wow i cant wait to see this hammer, something for utube?:o Quote Link to comment Share on other sites More sharing options...
rambo Posted January 5, 2009 Author Share Posted January 5, 2009 lol. im not about to post a vid. hehe. still, it is gonna take a bit of time cause im kinda stuck in 2 projects simultaniously. will up as soon as i can. Quote Link to comment Share on other sites More sharing options...
rambo Posted January 7, 2009 Author Share Posted January 7, 2009 Hi! All, Thanks for the interest, I finally have a sketch of the valve attached, I agree that without the existing design any suggestion would be difficult. The position of the valve is in neutral in the drawing, when the handle goes up the valve goes down and there is load on the handle which tends to take the handle up, which the operator struggles to control. I can see what John is saying, it is back pressure from the exhaust. Would like to see some standard designs of the valve which can eliminate/reduce the back pressure. We have not really copied any design but only tried to improvise our free forging hammer design to a die forging one based on experience and info available on the net. Quote Link to comment Share on other sites More sharing options...
rambo Posted January 8, 2009 Author Share Posted January 8, 2009 (edited) this is the pic of the hammer.... Edited January 8, 2009 by rambo Quote Link to comment Share on other sites More sharing options...
nonjic Posted January 8, 2009 Share Posted January 8, 2009 (edited) Wow, someones spent alot of $ building that thing and not really thought it through! I bet its "entertaining" to watch the hammer running........... There are many design faults with the valve youve sketched. primarily 1) Its to small diameter wise (I would have gone 7 or 8" min). you are trying to put to much steam through to small a gap. 2) there are no lead in chamfers / bleed holes anywhere on your design, either on the valve or in the valve tubes / valve chest. (which is going to make it 'jumpy' to say the least) 3) you have 2 exhausts, this is not necessary. you should always exhaust through the center of the valve spool for balance. I attach a very quick sketch of the style of spool valve I would fit. It is held onto the valve spindle with spiders. You do not need the bottom exhaust with this design of valve. Hope this is of some help. I can sell you designs and manufacturing drawings for the correct valve for a double acting steam stamp if you wish, email address available on index With correctly designed valving your hammer will have alot more forging energy and save a huge ammount of energy $. It must be very inefficient at the moment. hope this helps some, John Nicholson. Edited January 8, 2009 by John N Quote Link to comment Share on other sites More sharing options...
rambo Posted January 9, 2009 Author Share Posted January 9, 2009 Thanks John for your input. I would certainly like to re design the valve and chest. However, I need to start production and can simultaneously start making a new valve with your help. In the meanwhile I had an idea to improve the existing design, basically I am looking at reducing the 4 " length of the spindle in the middle to 3.5 ", the 2" size of the spools would remain the same. This way the valve exhaust would always be open by about 1/2" to allow quick release of the steam, thereby reducing the pressure build up on the valve. Do you think this might help? Please also send me a quote for the design suggested by you. Rambo Quote Link to comment Share on other sites More sharing options...
ptree Posted January 11, 2009 Share Posted January 11, 2009 Rambo, Much as I suggested the valve is unbalenced. The spool John N suggests is much as I woul suggest. I would work with John for a proper design. He has much experience in this area. Quote Link to comment Share on other sites More sharing options...
rambo Posted January 14, 2009 Author Share Posted January 14, 2009 Hi! John, I am waiting for quote from you. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.