Airlock Sizing Program

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To accurately size a rotary airlock valve based on material flow, it's essential to consider several key factors, including the desired conveying rate, material bulk density, valve efficiency, and rotor speed. Here's a step-by-step guide to help you through the process

Sizing Procedure

Step-by-Step Procedure for Rotary Airlock Valve Sizing

Step 1: Gather Essential Parameters

Conveying Rate (R):	Determine the required material flow rate, typically expressed in pounds per hour (lbs/Hr.) or kilograms per hour (kg/Hr.) or metric ton per hour (ton/Hr.)

Maximum Conveying Rate (R)	X	Lbs	per Hr.
(Enter X or Y or Z)	Y	Kg	per Hr.
	Z	Ton	per Hr.

Bulk Density (D):	Obtain the bulk density of the material, usually in pounds per cubic foot (lb/ft³) or kilograms per cubic meter (kg/m³) or tons per cubic meter (ton/m³).

Bulk Density (D):	S	lb/ft³
(Enter S or R or T)	R	kg/m³
	T	ton/m³

Valve Efficiency (E):	Estimate the valve's efficiency, which accounts for how completely the rotor pockets fill and empty. Product followability, pressure differential, type of feed to the valve, and rotor design can all affect this. Efficiency typically ranges between 65% and 85% (expressed as a decimal, e.g., 0.75 for 75%).

Valve Efficiency (E):

Step2: Calculate Required Swept Volume per hour

Use the following formula to determine the necessary volume per hour:

C=[R] / [D×E]

Where:

C = Required swept volume per minute (ft³/hr or m³/ hr)
R = Conveying rate (lb/hr or kg/hr)
D = Bulk density (lb/ft³ or kg/m³)
E = Valve efficiency (as a decimal)

This calculation provides the volume that the valve must handle per hour to meet the desired flow rate.

Valve Volume Capacity Required	Cubic feet / Hr	J
	Cubic meter / Hr	K
	Cubic feet / Min	M
	Cubic meter / Min	N

Once the sizing calculator provides the required valve volume capacity based on your input parameters, refer to the table below to identify the optimal combination of airlock size and valve RPM that meets or exceeds your requirement.

Example:

Let’s say your input parameters are:

Material Flow Rate (R): 10,000 lbs/hr
Bulk Density (D): 50 lbs/ft³
Valve Efficiency (E): 0.65
Using the sizing formula or calculator, you get:
Required Valve Volume Capacity = 307.69 ft³/hr

Next, refer to the sizing table below to find the smallest valve that can handle this volume at a practical operating speed — typically around 20 RPM.

In this example, an 8-inch airlock operating between 17 to 20 RPM would fulfill the requirement effectively.

✅ Tip: Always account for potential increases in future demand. It’s often advisable to select a valve with slightly higher capacity to ensure long- term scalability and performance.

Airlock Valve Capacity (Cubic Feet/Revolution)
Valve RPM		6	8	10	12	14	16
Cubic Feet / Rev.		0.15	0.31	0.58	1.11	1.63	2.50
Valve Capacity in Cubic Feet / Hr.
Valve RPM	10	93	188	349	666	978	1502
	11	102	207	384	733	1076	1652
	12	111	226	418	799	1173	1802
	13	120	245	453	866	1271	1953
	14	130	264	488	933	1369	2103
	15	139	282	523	999	1467	2253
	16	148	301	558	1066	1564	2403
	17	157	320	593	1132	1662	2553
	18	167	339	628	1199	1760	2704
	19	176	358	663	1266	1858	2854
	20	185	377	697	1332	1956	3004
	21	194	395	732	1399	2053	3154
	22	204	414	767	1466	2151	3304
	23	213	433	802	1532	2249	3455
	24	222	452	837	1599	2347	3605
	25	231	471	872	1665	2445	3755
	26	241	490	907	1732	2542	3905
	27	250	508	942	1799	2640	4055
	28	259	527	976	1865	2738	4206
	29	268	546	1011	1932	2836	4356
	30	278	565	1046	1999	2933	4506

Actual pocket fillage varies based on application. For optimum selection, please contact us; For feeding applications, 10 to 20 RPM generally provides most uniform discharge of product at greater fill efficiency

selection

Choose from the Following Rotary Airlock Valves

Heavy Duty Universal CI Series Heavy Duty Universal Stainless Quick Disconnect HD CI Series Quick Disconnect HD CI Series