SF 600 problem - Any help or advice would be appreciated

[Scott]

Glad to hear its working for you, good call on the fluid. I assumed that when you changed the fluid that you got the right stuff and put it out of my head. Assumption is the mother of all f%$*-ups, my bad..........

RRBD

[Thomas Vaught]

I used the "orifice calculator" to check the flow calculation for the SF calibration plate.

With an assumed .312 small hole and a 1.875 hole (at 25" H2O)
flowing together the numbers were:

.312 hole = 6.44 cfm
1.875 hole = 232.5 cfm

Total cfm assuming a .605 discharge co-efficient = 238.94
vs the spec of 238 cfm. Not bad.

Tom V.

[larrycavan]

It looks like you were reading about 73% when you should have seen about 53%.

Running the numbers for the scale with the two different fluids it makes sense.

328/450 = .728 [call it 73%]
238/450 = .528 [call it 53%]

With 1.0SG fluid, the water column at 73% is roughly 3.2". With 1.92SG fluid, the water column at 53% is roughly 3.2"

Give or take a tad bit...you're in the ball park for sure...

Glad you solved the problem..

Larry C

[larrycavan]

[John F]

Glad to hear the numbers make sense. I'll fill you all in on the results when I get the proper oil in it.

[gofaster]

I'm finding this thread to be very interesting. I'm glad that John F's problem has been figured out.

It raises a few questions in my mind, and maybe some of you guys have the experience/education to know the answers. My 246 inclined manometer from Dwyer came with "red" fluid, .826 sp. gr., and a square root scale. When I asked about using the violet fluid, Dwyer's engineer was adamant about sticking with the red fluid.

Would manometers have different bores for the use of different fluids?

Another thing I noticed is that the 246 came with significantly larger diameter vinyl tubing than I have on my SF-110. My manometers are in storage at the other shop now, but maybe later this weekend I'll have time to go get some measurements.

Does anybody have any ideas about how the vinyl tubing i.d. (connecting the manometers to the bench and the data acquisition unit) would affect readings?

A few months ago Tom V. posted posted up that the difference between the SF-300 and the SF-600 was the fluid.

Was it just a change in fluid, or is the manometer drilled differently?

My son saw the 246, and said his shop used to machine the durablocks for Dwyer, but he couldn't tell me much more about it. To a machinist, "parts is parts", they just make them to the print and don't need to know anything about them.

If I can find the time during the week, I'd like to run back up to Dwyer and talk face to face with the engineer and try to pick her brain on this, if she's still there. She said she may be getting transferred to Australia soon. I also think I should try to talk to Audie Thomas, if he has the time. I noticed that he sent an adaptor tube that is made from two sizes of tube joined to each other. Presumably to join my manometer to his data acquisition unit.

John F has had experiences similar to mine at Superflow. They must have one clown working there who is impossible to talk to. Harold B and some others there have treated me very well, but I've had problems with "somebody", too. That's the reason I bought my electronics from Audie instead of continuing with SF's FlowCom and PT. "Somebody" royally ticked me off.

[Mouse]

Tube diameter is important to reduce hysterisis. If the tube diameter is too small, surface tension between the fluid and tube surface create hysterises that will hinder the performance of the manometer.

Most high quality manometers use a special glass tubing, called Boron or Borite or something like that. Can't remember the name off hand. It is not hard to find though.

[Thomas Vaught]

The SF 110 bench used a different manometer.

The SF300 and the SF 1200 benches both used the red .826 manometer fluid. The SF600 bench used the 1.91 "blue" fluid. All three used the 246 inclined manometer.

Tom V.

[John F]

Just wanted to let you all know I put the new blue gauge oil in my incline manometer and the bench now works perfectly.

Thanks again for all your helpful info and advice guys.

[larrycavan]

[Thomas Vaught]

Expensive oil change but a proper one.

Tom V.

[John F]

Expensive indeed. That blue oil was $64 per ounce from Superflow. It takes 2.2 ounces to fill the manometer. Wonder what makes it so expensive?

[Thomas Vaught]

Because it has Super Flow's special mixture to get a 1.91 specific gravity. By the way you need to drain and refill the manometers every so often or the Blue fluid will impart residue on the tube of the manometer. You can use the same fluid, just shake it up after you drain it to help keep the stuff in suspension.

Personally, I have thought several times about
recalibrating a SF-600 type bench for a more robust fluid from a company like Merrium with a different specific gravity. I need to do more research on that deal but it may never happen if I switch over to Mouse's FP-1 instrumentation.

Tom V.

[larrycavan]