NFPA Design Rotary Airlock
The Drop Thru Rotary Airlock valve is our standard unit and is utilized in most applications. These valves are available in a round or square design.
Carolina Conveying’s rotary airlocks are a heavy duty design with thick castings, thick blade rotors with oversized shafts, outboard re-greaseable bearings, and gland type shaft seals.
Numerous rotor options are available:
- Open end, closed end, fixed blades, adjustable blades, beveled edges, scalloped pockets, reduced volume, quick release, Teflon coated, abrasion resistant tips, flexible rubber tips, and more.
Sizes available:
- 5, 6, 8, 10, 12, 14, 16, 18, 20, 24, 30 and 36 inch.
Applications vary from the bottom of dust collectors to pneumatic conveying.
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NFPA Design Rotary Airlock
The NFPA Design Rotary Airlock is a Heavy-Duty valve that meets or exceeds the requirements of NFPA 68 & 69 for rotary valves that are used for deflagaration isolation systems. These features are standard on Carolina Conveying’s Heavy Duty Rotary Airlock range and are available with Cast Iron and Stainless Steel construction.
Sizes available:
- 6” through 24”
- Round or Square Flanges
Features and Benefits:
- Heavy Duty Castings for Body and End Covers.
- Rotor robustly constructed with thick vanes and large shafts to ensure tight tolerances are held.
- An unlimited number of rotor options are available including open end, fixed blades, beveled edges, scalloped pockets, reduced volume, polished finishes, special coatings, abrasion resistant material, and many more.
- End covers are spigot located into the body for concentricity.
- The body, end covers and rotor are precisely machined in CNC center to ensure tight tolerances, minimal clearances between the rotor and housing, maximum pressure differential sealing, and minimal leakage.
- Outboard mounted ball bearings
- Gland type shaft seals with multiple rows of packing and design flexibility for air purging.
- Standard drives package includes high efficiency helical gearboxes that will accommodate any C Flange motor whether it is TEFC, explosion proof, chemical duty, inverter duty, wash down duty etc. Helical gear reducers transmit more torque than the industrial standard worm type reducers used by most of our competitors - requiring less power consumption and providing more energy savings.
NFPA Features:
- Heavy Duty Design & Construction
- Maximum 10 bar-g upset pressure
- Maximum Kst of 300 bar-m/sec
- Open End Rotors
- 8 Vanes Standard (exceeds the 6 required)
- Two vanes on each side in contact with the housing at all times
- Precision Machined Body, End Covers & Rotor
- Maximum rotor clearance of 0.0079” (CCI Standard is 0.004” to 0.006”)
- Outboard Regreasable Ball Bearings
- 6” through 24” sizes
Advantages:
- Cast Body and End Covers
- Available in Cast Iron & Cast Stainless Steel
- Abrasion Resistant Options available
- Precision Machined for Tight Tolerances
- Open End Beveled Edge Rotors minimize squealing and jamming
- Extra thick steel rotor vanes provide long life
- ASA 150# Bolt Hole Pattern on Round Units
- High Efficiency Helical Gearboxes
- Compact Design
- C-face motors
| Specifications | |
|---|---|
| NFPA 68 & 69 Rated | Heavy Duty Cast Construction |
| Precision Machined with Tight Tolerances | Cast Iron or Stainless Steel |
| Round or Square Flanges | Operating Pressure Differentials to 20 psi |
| Upset Pressure Ratings to 10 Barg | |
| INDUSTRIES | ||
|---|---|---|
| Food | Pharmaceutical | Animal Feed |
| Paint & Pigment | Power | Chemical |
| Systems | ||
|---|---|---|
| Dust Collection | Pneumatic Conveying | Bulk Material Handling |
| Types | ||
|---|---|---|
| Airlock only | Metering only | Airlock & Metering |
| Square Drop Thru Rotary Airlocks | |||||||||||||||||||
| Size | A | B | C | D | E | F | G | H | J | K | L | M | N | O | P | R | T | V | HP |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6 | 6 | 9 7/8 | 1/2 | 5 1/2 | 11 | 8 1/4 | 8 1/4 | 11 1/2 | 16 | 10 1/4 | 8 1/4 | 1 1/4 | 5 5/8 | 12 | 1/2 | 1/4 | 3 | 2 3/4 | 0.5 |
| 8 | 8 | 11 7/8 | 1/2 | 6 1/2 | 13 | 7 1/4 | 9 1/4 | 12 1/2 | 16 | 11 1/4 | 9 1/4 | 1 1/4 | 5 5/8 | 12 | 1/2 | 1/4 | 3 | 3 9/16 | 0.5 |
| 10 | 10 | 13 1/4 | 9/16 | 7 1/2 | 15 | 8 5/8 | 10 3/8 | 13 5/8 | 18 1/4 | 12 5/8 | 10 5/8 | 1 1/2 | 6 3/8 | 12 | 9/16 | 3/8 | 3 | 4 | 1 |
| 12 | 12 | 15 3/4 | 3/4 | 9 1/8 | 18 1/8 | 7 1/4 | 11 5/8 | 14 7/8 | 18 7/8 | 13 1/4 | 11 3/4 | 1 1/2 | 7 3/4 | 12 | 1/2 | 3/8 | 3 | 4 11/16 | 1 |
| 14 | 14 | 18 1/2 | 3/4 | 10 1/8 | 20 1/4 | 7 | 12 | 15 1/4 | 20 1/4 | 14 1/4 | 12 1/8 | 1 1/2 | 8 3/4 | 12 | 1/2 | 3/8 | 3 | 5 1/2 | 1 |
| 16 | 16 | 21 5/8 | 3/4 | 11 7/8 | 22 13/16 | 4 3/4 | 14 5/8 | 19 | 24 5/8 | 18 | 14 7/8 | 2 1/2 | 9 1/4 | 12 | 11/16 | 5/8 | 3 | 6/12 | 1.5 |
| 18 | 18 | 24 | 3/4 | 12 3/4 | 24 13/16 | 3 3/4 | 15 5/8 | 20 | 24 5/8 | 19 | 15 7/8 | 2 1/2 | 11 1/4 | 12 | 11/16 | 5/8 | 3 | 7 3/8 | 1.5 |
| 20 | 20 | 25 5/8 | 3/4 | 13 3/8 | 26 3/8 | 5 1/4 | 16 5/8 | 21 | 27 1/2 | 19 7/8 | 16 7/8 | 2 1/2 | 11 3/8 | 14 | 11/16 | 5/8 | 4 | 5 13/16 | 2 |
| 24 | 24 | 29 1/2 | 3/4 | 15 | 29 1/2 | 3 1/4 | 18 5/8 | 23 | 27 1/2 | 21 7/8 | 18 1/4 | 2 1/2 | 13 1/4 | 14 | 11/16 | 5/8 | 4 | 6 13/16 | 3 |
| Round Drop Thru Rotary Airlocks | ||||||||||||||||||
| Size | A | B | C | D | E | F | G | H | J | K | L | M | N | O | P | Q | R | HP |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6 | 6 | 11 1/4 | 1/2 | 5 1/2 | 11 | 8 1/4 | 8 1/4 | 11 1/2 | 16 | 10 1/4 | 8 1/4 | 1 1/4 | 5 5/8 | 8 | 7/8 | 9 1/2 | 1/4 | 0.5 |
| 8 | 8 | 13 1/2 | 1/2 | 6 1/4 | 12 1/4 | 7 1/4 | 9 1/4 | 12 1/2 | 16 | 11 1/4 | 9 1/4 | 1 1/4 | 5 5/8 | 8 | 7/8 | 11 3/4 | 1/4 | 0.5 |
| 10 | 10 | 16 | 9/16 | 7 7/8 | 15 | 8 5/8 | 10 3/8 | 13 5/8 | 18 1/4 | 12 5/8 | 10 5/8 | 1 1/2 | 6 3/8 | 12 | 1 | 14 1/4 | 3/8 | 1 |
| 12 | 12 | 19 | 3/4 | 9 1/2 | 18 5/16 | 7 1/4 | 11 5/8 | 14 7/8 | 18 7/8 | 13 1/4 | 11 3/4 | 1 1/2 | 7 3/4 | 12 | 1 | 17 | 3/8 | 1 |
| 14 | 14 | 21 | 3/4 | 10 5/8 | 20 1/2 | 7 | 12 | 15 1/4 | 20 1/4 | 14 1/4 | 12 1/8 | 1 1/2 | 8 3/4 | 12 | 1 1/8 | 18 3/4 | 3/8 | 1 |
| 16 | 16 | 23 1/2 | 3/4 | 11 7/8 | 22 13/16 | 4 3/4 | 14 5/8 | 19 | 24 5/8 | 18 | 14 7/8 | 2 1/2 | 9 1/4 | 16 | 1 1/8 | 21 1/4 | 5/8 | 1.5 |
| 18 | 18 | 25 | 3/4 | 12 5/8 | 24 5/8 | 3 3/4 | 15 5/8 | 20 | 24 5/8 | 19 | 15 7/8 | 2 1/2 | 11 1/4 | 16 | 1 1/4 | 22 3/4 | 5/8 | 1.5 |
| 20 | 20 | 27 1/2 | 3/4 | 13 3/8 | 26 3/8 | 5 1/4 | 16 5/8 | 21 | 27 1/2 | 19 7/8 | 16 7/8 | 2 1/2 | 11 3/8 | 20 | 1 1/4 | 25 | 5/8 | 2 |
| 24 | 24 | 32 | 3/4 | 15 3/16 | 29 15/16 | 3 1/4 | 18 5/8 | 23 | 27 1/2 | 21 7/8 | 18 1/4 | 2 1/2 | 13 1/4 | 20 | 1 3/8 | 29 1/2 | 5/8 | 3 |
Calculating Your Correct Valve Size
Valve size is based on volume. Throughput is usually expressed in lbs/hour or tons/hour, but for valve selection, the rate must be converted into cubic feet/hour.
∴ To calculate a valve throughput per hour:
Throughput lbs / hr
= cu. ft. / hr. capacity
Bulk Density lbs / cu. ft.
∴ Based on, say, 240,000 lbs / hr. at a bulk density of 80 lb /cu. ft.
Valve throughput required =
240,000 lb / hr
80 lb / cu. ft.
= 3000 cu. ft. / hr.
- The chart below shows valve size in the first column
- The top row lists the practical fill efficiency for most applications
- The bottom row lists the rotor RPM
- Comparing the valve size to the rotor RPM, the corresponding discharge rate is shown based on the practical fill efficiency
On this application two valves can be selected:
(a) 24” Valve @ 10 RPM @ 90% fill efficiency
(b) 20” Valve @ 20 RPM @ 78% fill efficiency
For products with very light bulk density (< 20 pcf), a lesser fill efficiency must be used to calculate valve size.
| Practical Capacity in Cubic Feet per Hour (CFH) | |||||||||||||||
| SIZE | CFR | 100% | 100% | 100% | 98% | 95% | 90% | 88% | 86% | 84% | 81% | 78% | 74% | 71% | 68% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 24 | 5.683 | 341 | 682 | 1364 | 2005 | 2591 | 3069 | 3601 | 4105 | 4583 | 4971 | 5319 | 5551 | 5810 | 6029 |
| 20 | 3.233 | 194 | 388 | 776 | 1141 | 1474 | 1746 | 2048 | 2336 | 2607 | 2828 | 3026 | 3158 | 3305 | 3430 |
| 18 | 2.333 | 140 | 280 | 560 | 823 | 1064 | 1260 | 1478 | 1685 | 1881 | 2041 | 2184 | 2279 | 2385 | 2475 |
| 16 | 1.667 | 100 | 200 | 400 | 588 | 760 | 900 | 1056 | 1204 | 1344 | 1458 | 1560 | 1628 | 1704 | 1768 |
| 14 | 1.017 | 61 | 122 | 244 | 359 | 464 | 549 | 644 | 735 | 820 | 890 | 952 | 993 | 1040 | 1079 |
| 12 | 0.7 | 42 | 84 | 168 | 247 | 319 | 378 | 444 | 506 | 564 | 612 | 655 | 684 | 716 | 743 |
| 10 | 0.38 | 23 | 46 | 91 | 134 | 173 | 205 | 241 | 275 | 306 | 332 | 356 | 371 | 389 | 403 |
| 8 | 0.19 | 11 | 23 | 46 | 67 | 87 | 103 | 120 | 137 | 153 | 166 | 178 | 186 | 194 | 202 |
| 6 | 0.069 | 4 | 8 | 17 | 24 | 31 | 37 | 44 | 50 | 56 | 60 | 65 | 67 | 71 | 73 |
| 5 | 0.039 | 2 | 5 | 9 | 14 | 18 | 21 | 25 | 28 | 31 | 34 | 37 | 38 | 40 | 41 |
| 1 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | ||
| Rotor Speed in RPM | |||||||||||||||
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