Proper Static Pressure Tip for filter monitoring?

[Dan Case LR]

I have an Oneida V3000 coming in a week or two, and just picked up a nice Dwyer Photohelic pressure gauge (0-5" water). If you're not familiar with the Photohelic, it's basically a Magnehelic with two adjustable trip points for alarms or other action (red lines on the gauge you can set wherever you want them). I plan to have a visual alarm at 3" and forced shutdown at around 4" to protect that expensive filter.

Dwyer has as many different static pressure tips as Walmart has things made in China. Which one should I use with the V-series? What does Oneida sell with their kit? Anyone know?

Thanks!

D.

[Michael W. Clark]

Hi Dan, you can use a tip, but it is not necessary for SP measurement. To measure SP, the hose end or measurement point should be perpendicular to the airflow. The simplest way is to drill a hole in the duct, then attach the hose so that it sticks through the hole slightly and use silicone to hold it in place and seal it. Another, more professional looking way is to drill the duct for a hose barb fitting and attach the fitting to the duct, then the hose to the fitting.

Mike

[Ole Anderson]

Hi Dan, you can use a tip, but it is not necessary for SP measurement. To measure SP, the hose end or measurement point should be perpendicular to the airflow. The simplest way is to drill a hole in the duct, then attach the hose so that it sticks through the hole slightly and use silicone to hold it in place and seal it. Another, more professional looking way is to drill the duct for a hose barb fitting and attach the fitting to the duct, then the hose to the fitting.

Mike +1 on that

[Tom Hartranft]

Dan,

Ref your interest in V3000 filter condition via static pressure tap.

I just took a couple of photos of my set up for my 2-year old metal V3000. I installed a 4-tap static pressure manifold on the inlet pipe of my V3000 (right side in photo) and a 2-tap static pressure manifold on the inlet to my filter element (left side in photo). I used 1/8 inch NPT with 1/4 inch hose barb for the pressure connections. I cut some hard maple scraps for the weldments on my inlet pipe and filter inlet then drilled and tapped them to accept the 1/8 inch NPT hose barb fittings. The hard maple was very good for tapping the pipe threads. Then I drilled a 1/16 inch dia hole through the pipes then glued the maple weldments over the drilled holes ... centering the maple piece tapped holes by mark one eyeball over the 1/16 inch dia static pressure tap hole. I used 1/4 inch tubing for my manifolds ... ordered T-fittings, etc to make up the manifolds. Carefully sand any burr off of the inside surface of the pipes of your drilled pressure taps ... and don't let anything protrude into the flow path as either would bias your true static pressure readings. The 4-tap V3000 inlet and 2-tap filter inlet manifolds accommodate turbulence and non-uniform velocity profiles at the two static pressure tap locations.

I put two magnehelic pressure gages side by side on top of my V3000 to be able to quickly see my V3000 inlet and filter inlet static pressures each time I start up my system. I have a blastgate at the outlet of each of my woodworking machines so I can isolate each one from the system. I run only one machine at a time. I benchmarked static pressures for each machine before getting any dust in the system so that I know what my static pressure performance was at optimal filter condition. In one of the two photos below, you can see a spreadsheet directly below my two magnehelic gages ... this is the 'as new' display of my V3000 inlet and filter inlet static pressure. So I can quickly detect an anomaly when I start the system up ... e.g. forgot to shut all but one blast gate, clog in system, etc. I included CFM in my spreadsheet since I mapped velocity profile in a straight section of my overhead 6 inch dia PVC pipe then converted to CFM per Dwyer online velocity mapping/CFM calculation instructions. This is not necessary, but I found it interesting to do as a performance benchmarking for my overall system.

FYI ... you can see on the 4th photo that both system inlet pressure and filter inlet pressure are a function of system set up -- differs depending on overall CFM which, in turn, is different for each woodworking piping/machine who's blast gate is open. So, that's another reason to benchmark each machine individually if you want to assess filter seasoning over time. After two years of light use, my filter inlet pressure has increased about 0.4 inches of H2O even though I've used compressed air radially outside to inside a couple of times to blow out the filter element. I attribute this to general seasoning ... embedded dust that just won't blow out under compressed air. So far, my max filter inlet static pressure has not gone above 1.4 inches H2O. If you are able to get higher system CFMs than mine with your larger inlet and newer V3000, then you should expect larger filter inlet static pressures too.

Tom