LIMS Air Hockey Table
Overview
The LIMS air hockey table can be used for applications with low-friction environments.
In the data shown below, the air hockey table was used to float a 6 and 8 inch clear acrylic disc. A portion of the holes on the surface of the air table were covered to increase pressure and flow.
Air Hockey Table Specifications
Manufacturer: KT Sports
Dimensions: 79” long 39” wide (inner table dimensions)
Hole spacing: 1” square intervals
Number holes: 79 x 39 total holes on table (before modification)
Modifications: covered 2x12 columns (12x79) on each side of table with clear packing table directly applied
to surface of table. Left uncovered 79 holes x 15 holes down center of table (long-ways)
Blower (Shop-Vac) Specifications
Manufacturer: Shop-Vac Corporation
Name: Ultra PRO
Model Number: 92L500A
12 Gallon 5.0 Hp
2” inner diameter flexible hose
Hose attached in blower mode, taped and held in place underneath table at plenum.
Pressure Measurements
Experimental Setup
1/4” hole drilled into bottom of plenum, 6” to the side of main blower intake
1/4” clear plastic hose inserted via press-fit into plenum (3/16” inner diameter)
Shop vac hose taped and held in place over plenum intake
In blower mode, our shop vac appears to be leaking extra air out through various extra vents. To test the impact of the extra leakage, we performed one test with the shop vac in standard blower operation, and a second test with the extra venting holes covered with tape.
Test 1: Water Column
Vertically displaced 5” of water in a 3/16” inner diameter flexible clear hose (10 ft long)
1 inch water = 0.036 PSI
With Shop-vac vents unblocked: 4 inches water displaced * 2 * (0.036 PSI/inch) = 0.288 PSI in plenum
With Shop-vac vents blocked (taped): 5 inches water displaced * 2 * (0.036 PSI/inch) = 0.36PSI in plenum
Test 2: Analog Differential Pressure Sensor
Model Number: ASCX01DN
Sensitivity: 4.5 Volts / PSI
One input to pressure sensor connected to 3/16” inner diameter clear plastic hose (6” long, with other end in plenum)
Second input to pressure sensor open to room atmosphere
With blower off: Measured Offset Voltage of Sensor = 0.293 Volts
Blower on, Shop-vac vents unblocked: 1.29 Volts / (4.5 Volts/PSI) = 0.285 PSI
Blower on, Shop-vac vents blocked (taped): 1.51 Volts / (4.5 Volts/PSI) = 0.33 PSI
Tabulated Results
Flotation Capability
Experimental Setup
From the results of the pressure test, we covered the extra vents on the shop vac. This results in a higher pressure in the plenum and should increase the amount of weight we can support.
Shop-vac connected in blower mode with extra vents taped over.
Shop-vac taped and held in place at plenum.
Results
We tested 2 different sized clear polycarbonate circular discs (6” diameter, 8” diameter).
6" disc can support ~1.5lbs before it begins to drag
8" disc can support ~4.85lbs before it begins to drag
