The Official Mercdog Flowbench thread - The Official Mercdog Flowbench thread

[larrycavan]

John,

If the valves work as planned, then here's how it can be adapted to the MSD type orifice bench.

I don't know why my mind's eye didn't see this yesterday.

[Thomas Vaught]

Larry and John,

I did a MSD style bench set-up like Larry's last pic
but used sliding Toilet Valves to turn off the unused motors. It worked very well but was a mechanical deal vs an automatic deal. Larry's
box does work though in the MSD bench.

Only other comment is: Larry do you have the vacuum motors reversed vs the box check valve operation?

Tom V.

[Mouse]

Yeah, I think Larry has the valve boxes on the wrong side of the motors, but that design should work.

Okay, here's how it goes....

You get some 6" pvc pipe and end caps. The end caps have to be flat on the inside. If not flat, then a piece of the FCPVC needs to be glued in to form a flat surface on the inside of the cap.

The flapper valve is installed inside the cap, the cap put onto a short section of the 6" pvc pipe, then the section of pipe silicon glued over the vacuum motor housing. Just like Larry has illustrated (but backwards).

No?

[Thomas Vaught]

One of the benches in the forum had a similar deal with a metal
"outer housing" surrounding the fan/ motor. The valve was on
the side Larry showed BUT this bench was a "suck" only bench
I believe.

Maybe that was what Larry was trying to copy.

If the bench was in exhaust mode I think the flapper valves would stay closed if the motor was not on (if the valve was designed to blow open under flow). If the bench was in "suck" mode I think it would also stay closed with the "blow open" type valve.

JMO

Tom V.

[Mousehouse1]

Here is a picture of my almost completed bench.

[larrycavan]

No, they're not reversed. The boxes would be built in the chamber on the right side of the bench when facing from the front.

They would go over the intake hole of the moter. An artist I'm not.

[larrycavan]

Tom - John,

Air path is exactly as it would be normally in the MSD bench. The one way valve gets sucked in toward the intake hole on the motor.

I also think a velocity stack over the intake hole would be a good idea to add to the setup. It seems to me there could be some loss of flow due to the imposition of the check valve in the air stream. The VStack may help to overcome the loss.
Then again, maybe it's nothing to worry about.

What do you think?

Larry

[larrycavan]

Mousehouse,

Your bench is looking good. Did you get your AC power figured out yet?

Larry

[Mouse]

Good looking bench Martin! That clear front plate is a good idea, you can see what orifice you have selected and that it is properly located. You forgot to turn on your laptop though!

Where did you get those trick switches with the lighted numbers?

John

[Mouse]

Larry,

Okay, now I see. If the motor housing is pressed against the divider board, then smaller sized PVC pipe could be used to make the valve chambers, maybe 4" or even 3". The trick is to figure out how to fit a flapper valve inside the pipe.

[Mousehouse1]

John I didn't forget to turn on the laptop. I don't have power to it yet. I just sat it there for the picture. I still need to hook up the laptop and the FP1 box. I am also looking forward to seeing your software and box work. I will post a picture when I get everything up and running.


I made the numbers out of reflective vinyl tape that I cut out on a graphics plotter.

Larry I am suppose to finish the wiring tonight if I get time. I should have the bench running by this weekend.

[larrycavan]

[Thomas Vaught]

I have seen the motors mounted on either side of the dividing wall but SF used to RTV the motors to the wall which made it a real bear to replace one. I like the motor retention deal where the drum of the motor sits in a support cradle and a retention bar holds several motors to the dividing wall.

If you mounted the motors with the drum on the inlet side of the wall and the motor extending through the wall you can use normal fasteners to hold the motor securely to the dividing wall (the screw into the motor bosses). This would also allow more room for a larger check valve with the outer diameter of the checkvalve covering the motor drum and attaching to the wall. One more thing to remove in a repair but the large check valve area would not limit flow to the motor, (based on Larry's design). The other way would be as Larry has posted: motor on one side, check valve on the other.

Larry, on the velocity stack deal, I just radius the opening of the hole in the divided wall and make the hole the same size as the inlet hole of the motor. The radius acts like the venturi stack.

JMO

Tom V.

[larrycavan]

Tom,

I'll buy that. It makes perfect sense to use the cabinet divider as a stack.

I've had great success using one 2.035" orifice for both intake and exhaust tests. Yes the Cd is different for each direction.

Larry

[Mousehouse1]

Since the orifice disk is a place of leakage why not get rid of it and use a plate type system? Chad & I were talking about this earlier. If you could make a frame to hold each plate and install them through the fixture hole or make a hole in the front of your bench like the superflow 1200.

Each orifice plate could be a 3 1/2 to 4" square.