Re: 1904 Square Head Fasteners....What Grade ?


[Follow Ups] [Post Followup] [Dodge Power Wagon Forum]


Posted by David Sherman [72.47.9.228] on Tuesday, January 04, 2011 at 17:06:23 :

In Reply to: 1904 Square Head Fasteners....What Grade ? posted by Paul (in NY) [12.64.102.112] on Tuesday, January 04, 2011 at 15:55:42 :

I can't say exactly what grade of bolts are needed, but the dome is an air spring so it really isn't subject to any significant shock. It's the feed pipe just upstream of the clack valve that gets the shock. Obviously if the air chamber fills up with water, such as due to a leaking gasket, it will get a big shock, but normally it shouldn't be carrying much more than the static head of water in the outlet pipe (in psi, roughly half the height of the storage tank in feet). These old machines were designed more by seat-of-the-pants than by engineering calculations, since it was easier to add more cast iron and bigger bolts than to precisely calculate the stress in every part and precisely control the characteristics of the materials used. I'm thinking there's a huge safety factor in those 9/16 bolts.

I'm glad you intend to use this thing. There aren't many that are still in use. I think the last I saw (or rather heard) was on a farm in Southern Oregon 20 years ago. The air dome serves to push the water up the outlet pipe in between pulses. Think of what would happen without the air dome: when the clack valve closes, the pressure would jump, the check valve to the outlet pipe would try to open, but nothing would happen until the water in the outlet pipe started to move. You'd basically have inlet inertial fighting outlet inertia, and the result would be extremely high pressures and little movement of water. With the air dome, the check valve can open immediately and the impulse of water can go into the air dome, compressing the air. After the check valve closes, the compressed air pushes the water up the outlet pipe, so that there is a relatively steady flow in the outlet pipe and no extreme pressure spikes.

I notice you have some electronic equipment in in the back there, so think of it like a flyback converter, such as is used for generating the second anode voltage in a tube-powered TV. The inlet water is the B+ supply. The clack valve is the 6CD6 horizontal output tube. The check valve to the air chamber is the 1B3 high voltage rectifier, and the air chamber is the capacitance of the CRT's aquadag coating.



Follow Ups:



Post a Followup

Name:
E-Mail:
Subject:
Message:
Optional Link
URL:
Title:
Optional Image Link
URL:


This board is powered by the Mr. Fong Device from Cyberarmy.com