Fans and Ventilation

A Practical Guide

William Cory

• Publisher: Elsevier Science
• Year: 2010
• ISBN:
  9780080531588
• Topic: Tecnología e ingeniería
• Subtopic: Ingeniería mecánica

The practical reference book and guide to fans, ventilation and ancillary equipment with a comprehensive buyers' guide to worldwide manufacturers and suppliers.

Bill Cory, well-known throughout the fans and ventilation industry, has produced a comprehensive, practical reference with a broad scope: types of fans, how and why they work, ductwork, performance standards, testing, stressing, shafts and bearings.

With advances in technology, manufacturers have had to continually improve the performance and efficiency of fans and ventilation systems; as a result, improvements that once seemed impossible have been achieved. Systems now range in all sizes, shapes, and weight, to match the ever increasing applications.

An important reference in the wake of continuing harmonisation of standards throughout the European Union and the progression of National and International standards. The Handbook of Fans and Ventilation is a welcome aid to both mechanical and electrical engineers.

This book will help you to… •Understand how and why fans work •Choose the appropriate fan for the right job, helping to save time and money •Learn installation, operational and maintenance techniques to keep your fans in perfect working order •Discover special fans for your unique requirements •Source the most appropriate equipment manufacturers for your individual needs

• Helps you select, install, operate and maintain the appropriate fan for your application, to help you save time and money
• Use as a reference tool, course-book, supplier guide or as a fan/ventilation selection system
• Contains a guide to manufacturers and suppliers of ventilation systems, organised according to their different styles and basic principles of operation

1

Fan history, types and characteristics

Contents:

1.1 Introduction

1.2 Ancient history – “Not our sort of fan”

1.2.1 The advent of mechanical air movement using “air pumps” and fires

1.2.2 Early mine ventilation fans

1.2.3 The dawn of tunnel ventilation

1.2.4 The first Mersey road tunnel

1.2.5 Mechanical draught

1.2.6 Air conditioning, heating and ventilation

1.2.7 Developments from the 1930s to the 1960s

1.2.8 More recent tunnel ventilation fans

1.2.9 Longitudinal tunnel ventilation by jet fans

1.2.10 The rise of the axial flow fan

1.3 Definitions and classification

1.3.1 Introduction

1.3.2 What is a fan?

1.4 Fan characteristics

1.5 Centrifugal fans

1.5.1 Introduction

1.5.2 Forward curved blades

1.5.3 Deep vane forward curved blades

1.5.4 Shrouded radial blades

1.5.5 Open paddle blades

1.5.6 Backplated paddle blades

1.5.7 Radial tipped blades

1.5.8 Backward inclined blades

1.5.9 Backward curved blades

1.5.10 Reverse curve blades

1.5.11 Backward aerofoil blades

1.5.12 General comment

1.6 Axial flow fans

1.6.1 Introduction

1.6.2.2 Vane axial fan (downstream guide vanes – DSGV)

1.6.2.3 Vane axial fan (upstream guide vanes – USGV)

1.6.2.4 Vane axial fan (upstream and downstream guide vanes – U/DSGV)

1.6.2.5 Contra-rotating axial flow fan

1.6.3 Blade forms

1.6.3.1 Free vortex

1.6.3.2 Forced vortex

1.6.3.3 Arbitrary vortex

1.6.4 Other types of axial flow fan

1.6.4.1 Truly reversible flow

1.6.4.2 Fractional solidity

1.6.4.3 High pressure axial fans

1.6.4.4 High efficiency fans

1.6.4.5 Low-pressure axial fans

1.7 Propeller fans

1.7.1 Impeller construction

1.7.2 Impeller positioning

1.7.3 Diaphragm, ring or bell mounting

1.7.4 Performance characteristics

1.8 Mixed flow fans

1.8.1 Why the need - comparison of characteristics

1.8.2 General construction

1.8.3 Performance characteristics

1.8.4 Noise characteristics

1.9 Miscellaneous fans

1.9.1 Cross flow fans

1.9.2 Ring shaped fans

1.10 Bibliography

In an age when political correctness has become the state religion, it is perhaps courting disaster to tell a joke about our fellow human beings. That it might be interpreted as racist by the professional do-gooders is doubly worrying. However, as a man of English-Scottish ancestry and with Welsh-Irish wife I feel impervious to such slings and arrows.

“Excuse me, my good man”, said an Englishman lost in the wilds of Ireland. “Can you tell me the way to Ballykelly?” “If I were you, sir, I wouldn’t start from here.”

A perfectly correct and helpful answer. It’s just the same with the fan world. We shouldn’t have started when and where we did. But the die was already cast and a line from there to the present day shows us the path we trod. There were numerous setbacks and diversions, but an extension of that line, shows us the direction to the future. If we have studied that history, we may even avoid making the same mistakes twice, and will not have to suffer the old “Codger” in the corner saying “We tried that in 1961 and it didn’t work”.

To maintain the interest of those who like to classify and define, the Chapter continues with a description of the various fan types in what is hopefully a logical progression. It describes the shape of the characteristic curves, but the reader’s patience will be rewarded in the Chapters that follow.

1.1 Introduction

It is inevitable that the content of this chapter will reflect the personal experiences, and indeed preferences, of the author. Apologies are, therefore, proffered in advance to those companies whose products are conspicuous by their absence. The privilege of all historians is to be able to “slant” the investigations to suit their own individual prejudices – and I am no exception.

Mechanical fans are a particularly mature product – they have been around, and running most of the time, since at least the sixteenth century. Engineers will be the first to acknowledge that nothing is new, and most of the major design principles had been established by the early twentieth century. We, who have followed, have merely improved, tinkered with, or fitted theories to that which our fathers invented. We are but pygmies, standing on the shoulders of giants.

To appreciate the present and future developments, it is essential to know something of the past. Where we have come from gives us a direction as to where we might go in the future. It may also help to explain why there are so many different types of fan. The reasons for their existence are invariably that they met a customer need. Whilst managing directors may complain that they have half a million models in their manufacturing range, the chief engineer may reflect that if he or she were to meet all the requirements of flowrate, pressure and efficiency in the presence of hot, erosive and/or corrosive gases then an even larger range might be desirable.

1.2 Ancient history — “Not our sort of fan”

Few people ever pause to think that fan making is one of the oldest crafts in the world and that it dates back to the earliest times of which we have any clear record. The use of fans was already well established in the earliest Egyptian civilizations. This is made clear by the ancient bas reliefs in the British Museum, which depict women carrying feather fans. There is further evidence of the fact in the Cairo Museum, where there still exists the remains of a fan found in the tomb of Amenhotep, who died as far back as 1700 BC.

The royalty and notabilities of the ancient dynasties undoubted...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Foreword
• Dedication
• About the author
• Using this book
• Chapter 1: Fan history, types and characteristics
• Chapter 2: The properties of gases
• Chapter 3: Air and gas flow
• Chapter 4: Fan performance Standards
• Chapter 5: Fans and ducting systems
• Chapter 6: Flow regulation
• Chapter 7: Materials and stresses
• Chapter 8: Constructional features
• Chapter 9: Fan arrangements and designation of discharge position
• Chapter 10: Fan bearings
• Chapter 11: Belt, rope and chain drives
• Chapter 12: Shaft couplings
• Chapter 13: Prime movers for fans
• Chapter 14: Fan noise
• Chapter 15: Fan vibration
• Chapter 16: Ancillary equipment
• Chapter 17: Quality assurance, inspection and performance certification
• Chapter 18: Installation, operation and maintenance
• Chapter 19: Fan economics
• Chapter 20: Fan selection
• Chapter 21: Some fan applications
• Chapter 22: Units, conversions, standards and preferred numbers
• Chapter 23: Useful fan terms translated
• Chapter 24: Guide to manufacturers and suppliers
• Chapter 25: Reference Index
• Acknowledgments
• Index to advertisers