Grizzly G5954 owner manual Calculating Duct Resistance, Duct Approximate Dia, Loss Per Foot

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Calculating Duct Resistance

Adding duct work, elbows, branches and any other components to a duct line increases airflow resistance (static pressure loss). This resistance can be minimized by using rigid (smooth) pipe and gradual curves, as opposed to flexible pipe and 90˚ elbows.

The purpose of calculating the resistance is to determine if it is low enough from the machine to the dust collector to meet the given CFM require- ment for the machine. Use the charts in Figure 22 to calculate the resistance of duct work.

Duct

Approximate

Approximate

Dia.

Static Pressure

Static Pressure

 

Loss Per Foot of

Loss Per Foot

 

Rigid Pipe

of Flex Pipe

 

Main

Branch

Main

Branch

 

Lines

Lines

Lines

Lines

 

at 3500

at 4000

at 3500

at 4000

 

FPM

FPM

FPM

FPM

 

 

 

 

 

2"

.091

.122

.35

.453

 

 

 

 

 

2.5"

.08

.107

.306

.397

 

 

 

 

 

3"

.071

.094

.271

.352

 

 

 

 

 

4"

.057

.075

.215

.28

 

 

 

 

 

5"

.046

.059

.172

.225

 

 

 

 

 

6"

.037

.047

.136

.18

 

 

 

 

 

7"

.029

.036

.106

.141

 

 

 

 

 

8"

.023

.027

.08

.108

 

 

 

 

 

9"

.017

.019

.057

.079

 

 

 

 

 

 

 

 

 

 

Fitting

90˚

45˚

45˚

90˚

Dia.

Elbow

Elbow

Wye(Y)

Wye(Y)

 

 

 

 

 

3"

.47

.235

.282

.188

4"

.45

.225

.375

.225

5"

.531

.266

.354

.236

6"

.564

.282

.329

.235

 

 

 

 

 

7"

.468

.234

.324

.216

 

 

 

 

 

8"

.405

.203

.297

.189

 

 

 

 

 

Figure 22. Static pressure loss charts.

In most small/medium shops it is only necessary to calculate the line with the longest duct length or the most fittings (operating under the assumption that if the line with the highest resistance works, the others will be fine).

G5954 5HP Dust Collector

To calculate the static pressure of any given line in the system, follow these steps:

1.Make a list of each size duct in the line, includ- ing the length, and multiply those numbers by the static pressure value given in Figure 22.

2.List each type of elbow or branch and multiply the quantity (if more than one) by the static pressure loss given in Figure 22.

3.Add any additional factors from Figure 23.

Note: Always account for a seasoned filter, so you don't end up with a system that only works right when the filter is clean.

Additional Factors

Static Pressure

 

 

Seasoned (well used)

1"

Dust Collection Filter

 

 

 

Entry Loss at Large

2"

Machine Hood

 

 

 

Figure 23. Additional static pressure factors.

4.Total your list as shown in Figure 24 to come up with your overall static pressure loss.

Note: When determining static pressure loss over multiple lines, only count the main line numbers once.

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Figure 24. Totaling static pressure numbers.

5.Compare the total static pressure loss for that line to the closest CFM given in the Performance Curve section on the data sheet for your machine (located toward the front of this manual).

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Contents Model G5954 HP Dust Collector Page Table of Contents Introduction ForewordContact Info Machine Data Sheet 21.9 cu. ft Max CFM Max SP Volts Amps Inlet Dia Impeller Dia Static Pressure Inch/H2OSafety Instructions for Machinery SafetyAlways Lock Mobile Bases if Used Before Operating Machinery Additional Safety for Dust Collectors Circuit Requirements 220V Single-PhaseInventory SET UPSmall Component Inventory Figure Qty Other Components and Hardware QtyCleaning Site ConsiderationsWorking Clearances Base and Motor/Fan To attach the collectors to the motor/fan assemblyCollector Components and Hardware Needed QtyCollection Bags To set up the collecton bagsOperations Operation Safety GeneralDuct Material Metal DuctFlexible Duct Plastic Duct Decide Who Will Design System Design Sketch Your Shop Layout Sketch a Basic Duct LayoutDetermine Required CFM of Each Machine Machine ApproximateMachine Determining Main Line Duct Size Determining Branch Line Duct SizeTotal CFM Branch Line Size Duct Approximate Dia Calculating Duct ResistanceLoss Per Foot Fitting 90˚ 45˚ Dia Elbow WyeYFlex-hose grounded to machine System GroundingReducers & Adapters AccessoriesElectrical Components Model G5954 Switch WiringWiring Diagram G5954 Parts Breakdown Description G5954 Parts ListWarranty and Returns Page Page