Title: Unit 5 Outline
Course: HET 230 - Spring 2015 > Section: HET 230 - Spring 2015

Unit 5 Outline

Unit 5 Outline
Unit 5 Outline

Introduction:

Last week, we discussed sizing and calculating pressure losses in ductwork.  It is important that a technician have a very good understanding of these principles when working with this week’s topics. Along with safety, knowing pressures losses are important for the technician to determine the proper sizing and the specific type of fan for a system.

This week, you will become familiar with fan safety and discover the many types of fan configurations, as well as their use, including common vocabulary terms.  In addition, you will be provided a PowerPoint a presentation, weekly study materials. You will also participate in weekly discussions and complete all assignments and a content assessment quiz.  A proficient technician understands the hazards of working on, not only smaller fans, but also larger fan assemblies.  There can be many dangers consisting of stray airflow that can create the rotation of the fan blades, not using proper blocking procedures and not properly using locking out or tagging out procedures.  Understanding the many different types of fans, blade configurations and rotation is particularly important to the technician, who needs to know when confronted with diagnosing a certain airflow problem.  Learning these subjects will allow you to form a solid foundation for the next week’s session, Fan Curves and Fan Tables & System Effects.

Objectives:

On completion of this week’s assignments, the student should be able to:

- demonstrate the proper procedures for preforming Lockout/ Tagout
- become familiar with how to safely Block Out fan blades while working on motors
- understand the dangers of moving and rotating parts
- explain the importance of Belt Guards and why they must be installed
- describe the proper safety procedures and precautions before entering and leaving a Plenum; and why it can be extremely dangerous area to work
- understanding electrical safety while working in a Plenum
- describe the two general types of fans found in air systems
- identify what Centrifugal and Axial Fans are; and how to identify the differences between them
- name the four values used to describe the operating characteristics of a fan
- describe and name the components which make up Centrifugal Fans
- list the different types of blades of Centrifugal Fans
- explain the difference between an Airfoil-Blade and a Radial-Blade Fan
- describe what a Tubular and Plug Centrifugal Fans
- become familiar with the designations of Centrifugal Fans; identify impeller rotation and airflow direction
- understand the difference between clockwise (CW) and counterclockwise (CCW) fan rotation
- discuss classes of construction of Centrifugal Fans
- distinguish between Tubeaxial and Vaneaxial fans and difference between belt driven and direct drive
- explain the differences between a fixed and a variable pitch blade

Key Vocabulary:

Airfoil-blade Fan

Axial Fan

Centrifugal Fan

Clockwise (CW)

Counterclockwise (CCW)

Close Quarters

Cut-off

Backward-curved-blade (BC)

Backward-inclined-blade (BI)

Belt Guards

Block Out

Blower

Direction of Flow

Disconnect Switch

Double Width, Double Inlet Fans (DWDI)

Fixed Pitch

Forward-curved-blade (FC)

Housing

Inlet cone

Lockout/Tagout

Paddle-wheel Fan

Pitch

Plug Fan

Propeller Fan

Radial-Blade Fan

Rotating Equipment

Single Width, Single Inlet Fans (SWSI)

Squirrel Cage

Tubeaxial Fan

Tubular Centrifugal Fan

Vaneaxial Fan

Variable Pitch

Vortex

Wheel