Tractorsport Flowbench Forum Archive

Posted: **Thu Jul 14, 2005 9:03 am**

Has anyone else used the hot rodding or mercdog plans? I am not happy with the threaded metal blocks that holds the threaded rods which attaches to the valve bowls. Does anyone have any good ideas on what to replace them with or something that works better?

The threaded rods are to loose in the metal blocks and I don't think they will seal very well.

Posted: **Thu Jul 14, 2005 9:14 am**

Martin
This is what I did. I had a piece of 3/8 tube welded to a mounting plate. The I got a all thread coupler and welded it to the end. It's about 10 inches long. It makes a real sturdy and a good support for the bowl.

Chad

Posted: **Thu Jul 14, 2005 10:55 am**

Thanks Chad. That is what I should have used from the beginning.

Posted: **Thu Jul 14, 2005 6:52 pm**

Much better to toss out those horrid flow control valves, and control the speed of the blower motor(s) with a variac.

It will make a significant reduction to the noise level and power consumption as well as making the construction of the bench a lot simpler.

Posted: **Thu Jul 14, 2005 10:00 pm**

Okay Tony explain or show me a picture of how you would do it without the valves. My bench is identical to Chads except I haven't finished it yet.

Posted: **Thu Jul 14, 2005 11:29 pm**

The simplest way for you to accomplish what Tony is suggesting is to use your existing valves merely to control the direction of the air flow and use the variac to control air flow volume. IWO, open the appropriate valve all the way and adjust the motor speed with the variac to control the flow rate.

Posted: **Thu Jul 14, 2005 11:57 pm**

Where can I get a variac? I am using 8 vacuum motors. Do I need to control all of them or just a few?

Posted: **Fri Jul 15, 2005 12:29 pm**

Check ebay, there's always a few there. And one or two blowers on the variac should be fine, switch the remaining blower individually so that you can stage them, so that when you've got the variac at maximum and want more flow, you can just switch on another blower

Posted: **Fri Jul 15, 2005 2:51 pm**

Is there a certain type, brand or size I should look for or just buy any variac?

Posted: **Fri Jul 15, 2005 5:49 pm**

Just get any one that operates in the right voltage and current range for the blowers you're using. For what might be a lower cost alternative, check out .

Posted: **Sat Jul 16, 2005 2:08 am**

[color=#000000]I am currently building a flow bench.

I will be using 6/240 volt blower/vacuum motors. They draw 5 amps a leg when running. I will be using 4 variac

Posted: **Sat Jul 16, 2005 9:05 am**

[color=#000000][quote="Hopper"]don

Posted: **Sat Jul 16, 2005 10:09 am**

I'd given some though to the same problem but, rather then use a mechanical or electrically operated valve, I'd planned on constructing one that's operated by the air flow within the bench. It would operate very much like the draft control on a chimney consisting, a butterfly valve on the inlet side of each blower, it would have its shaft mounted horizontally and slightly above centre so that the butterfly would naturally fall closed and any air backing up through the blower would hold it closed but when the blower is turned on, the air flow entering the inlet of the blower would push the butterfly open.

Posted: **Sat Jul 16, 2005 6:39 pm**

If you want to do it that way, why not use an ordinary automotive throttle body ?

One problem you will have is that the flow is very non linear with butterfly position, but that can be fixed by using a system of bell cranks or a snail cam with roller follower on the end of an arm.

After having been through all this myself, I still feel very strongly that controlling blower speed electrically is by far the best method of flow control.

Tractorsport Flowbench Forum Archive

Bracket for mounting valve bowls