The design of an industrial agitator involves a series of sequential mechanical and chemical engineering calculations to ensure efficient mixing and structural integrity. A "repack" typically refers to consolidated spreadsheet tools that automate these formulas for quick process design or bidding. 1. Calculate the Impeller Reynolds Number ( NRecap N sub cap R e end-sub
The first step is determining the flow regime (laminar, transition, or turbulent) based on the fluid properties and impeller speed.
NRe=D2⋅N⋅ρμcap N sub cap R e end-sub equals the fraction with numerator cap D squared center dot cap N center dot rho and denominator mu end-fraction : Impeller diameter ( : Rotational speed ( : Fluid density ( : Dynamic viscosity ( 2. Determine the Power Number ( Npcap N sub p
The dimensionless Power Number depends on the impeller type (e.g., turbine, propeller, anchor) and the presence of tank baffles. Fully Turbulent Flow: Npcap N sub p is typically constant for a given geometry. Viscous Fluids: An actual Npcap N sub p is calculated by applying a viscosity power factor ( fμf sub mu ) based on the NRecap N sub cap R e end-sub 3. Calculate Power Requirements The basic power requirement ( ) is derived from the power number and fluid properties.
P=Np⋅ρ⋅N3⋅D5cap P equals cap N sub p center dot rho center dot cap N cubed center dot cap D to the fifth power
Total Motor Horsepower: To find the final motor size, standard losses must be added: Agitator Design Spreadsheet - PVtools
Agitator Design Spreadsheet. Page 1. Agitator Design Spreadsheet. Version 1.5. pvtools.weebly.com. 1/5. Page 2. Details. Version : Agitator design calculation xls
To create an agitator design calculation sheet, you need to structure your Excel workbook to handle four primary stages: Geometry definition, Fluid properties, Power requirement calculations, and Shaft/Impeller sizing. 1. Define Reactor & Impeller Geometry agitator design calculation xls repack
Input the physical dimensions of your vessel and the desired agitator setup. Tank Diameter ( : The internal diameter of the reactor vessel. Liquid Level ( : The height of the fluid in the tank. Impeller Type
: Choose from common designs like Pitched Blade Turbines, Rushton 6-Blade, or Propellers. Impeller Diameter ( : Typically calculated using a ratio, often ranging from 0.3 to 0.5. 2. Enter Fluid Properties
These variables are critical for determining the flow regime. : Measured in Viscosity ( : Measured in Pascal seconds ( ) or Centipoise ( 3. Core Calculation Formulas
Set up your Excel cells to automatically compute these values: Reynolds Number ( cap N sub cap R e end-sub : Determines if the flow is laminar or turbulent. is agitator speed in revolutions per second ( Power Requirement ( cap N sub p
(Power Number) is a dimensionless value specific to each impeller design. Motor Selection
: Add a safety margin (often 20-30%) to the calculated power to select a standard motor size. 4. Mechanical Design (Shaft Sizing) Ensure the shaft can handle the torque and bending moments. cap T sub m Bending Moment ( cap M sub m : Calculate the force at the point of jamming. Shaft Diameter (
: Use the equivalent bending moment formula to find the minimum diameter based on the material's yield stress (e.g., Stainless Steel). Available Resources & Templates The design of an industrial agitator involves a
If you prefer not to build from scratch, you can find pre-made templates through these sources: Chemical Process Engineering
: Offers a professional "Agitator Power Calculation" template (HCPE-MMP-0030) that includes power curve data for paddles, turbines, and propellers. Scribd - Agitator Design & Power Calculations
: A detailed guide for calculating mixing intensity and reactor geometry. Scribd - Agitator Shaft Diameter Calculation
: Focused specifically on the mechanical integrity of the agitator shaft. cap N sub p
for different impeller types to include in your spreadsheet? Agitator Design and Power Calculations | Chemical Reactor
Agitator design calculations, often implemented via Excel spreadsheets, determine critical parameters including Reynolds number, power number, and motor power requirements based on impeller type, flow regime, and vessel baffles. These tools facilitate essential mechanical design by calculating torque and ensuring shaft speed operates safely below the first critical speed. Technical guides and full design calculations are available for review on Scribd. Tank agitator power calculation - My Engineering Tools
Agitator design calculations are fundamental for ensuring efficient mixing, heat transfer, and structural integrity in chemical reactors and blend tanks. An Excel-based "repack" approach typically streamlines these complex mechanical and process variables into a user-friendly automated template. Core Design Components Diameter: 1
Designing an agitator involves balancing the process fluid requirements with mechanical constraints.
Process Parameters: Defined by the fluid properties (density and viscosity) and the required mixing intensity.
Impeller Selection: Choosing the type (e.g., Pitched Blade Turbine, Rushton, or Marine Propeller) based on whether axial or radial flow is needed. Vessel Geometry: Dimensions such as tank diameter ( ), liquid height ( ), and the presence of baffles to prevent vortex formation. Key Calculation Steps
A standard design workbook, such as those found on PVtools or Scribd, follows these steps: Types of Agitators, Agitator's Design and Significance
[ Re = \frac\rho \cdot N \cdot D^2\mu ] Determines turbulence level for power correlation.
Click a button (non-VBA, using Excel's Goal Seek or Solver add-in). The sheet adjusts impeller speed to reach a target power per volume (e.g., 2 kW/m³).
Unlike media files, engineering spreadsheets often contain VBA macros that:
When a “repack” cracks these protections, the cracker must modify VBA project passwords or patch compiled code. This frequently introduces:
Several industrial incidents (reported in CFM magazine) traced miscalculated agitator shafts to pirated spreadsheets.