The mushroom cultivator. A practical guide to growing mushrooms at home

Paul Stamets. The mushroom cultivator. A practical guide to growing mushrooms at home. - Agarikon press, 1983

Содержание

FOREWORD by Dr. Andrew Weil

PREFACE

I. INTRODUCTION TO MUSHROOM CULTURE

II. STERILE TECHNIQUE AND AGAR CULTURE

III. GRAIN CULTURE

IV. THE MUSHROOM GROWING ROOM

V. COMPOST PREPARATION

VI. NON-COMPOSTED SUBSTRATES

VII. SPAWNING AND SPAWN RUNNING IN BULK SUBSTRATES

VIII. THE CASING LAYER

IX. STRATEGIES FOR MUSHROOM FORMATION (PINHEAD INITIATION)

X. ENVIRONMENTAL FACTORS: SUSTAINING THE MUSHROOM CROP

XL GROWING PARAMETERS FOR VARIOUS MUSHROOM SPECIES

XII. CULTIVATION PROBLEMS AND THEIR SOLUTIONS: A TROUBLESHOOTING GUIDE

XIII. THE CONTAMINANTS OF MUSHROOM CULTURE: IDENTIFICATION AND CONTROL

XIV. THE PESTS OF MUSHROOM CULTURE

XV. MUSHROOM GENETICS

APPENDICES

GLOSSARY

BIBLIOGRAPHY

INDEX

PHOTOGRAPHY AND ILLUSTRATION CREDITS

ACKNOWLEDGEMENTS

OCR
350/Appendix II: Laminar Flow Systems
greater capacity for holding dust. As the filter traps dust, it increases in weight and airflow declines.
Generally a HEPA filter is not reused but discarded when, as a rule of thumb, the resistance or
"pressure drop" doubles. Extended surface filters are used in hospital surgery rooms as well as culture laboratories and nuclear facililties. Since its efficiency is somewhat dependent on the impact
velocity of the particle striking the media web, an appropriate fan must be matched with this type of
filter.

The Fan
When constructing a laminar flow hood, the filter size must be precisely fitted with a high pressure fan. All fans are rated by the manufacturer according to the volume of air (CFM or cubic feet
per minute) they can push past materials of specified resistance. The type of high pressure fans
needed in a laminar flow hood are usually of the squirrel cage type ("furnace blowers").
In turn, the resistance of all micron filters are measured in inches of static pressure at a certain
air speed. A standard resistance for a micron filter of this type is .75-1 .00 inches of static pressure.
Because extended surface filters have a high initial resistance, the housing must tightly hold the
HEPA filter so that impure air is not sucked into the exiting airstream.

To calculate the correct fan/filter combination, take the net CFM of the fan at the filter's rated
level of resistance and divide that number by the square footage of the filter face. Ideally, that number will be 100 feet per minute, the optimum range for air velocity in laminar flow systems. An example will more clearly illustrate this basic principle.
IF a micron filter measures 2 feet long by 2 feet high by 6 inches deep and has a static pressure
rating of 1 .0 inches of resistance, the fan required would have to be capable of pushing 400 CFM
at 1 inch of static pressure.

IF X = the desired net CFM of a fan at 1" S.P. and
Y = 4 square feet (the square footage of the filter face)

THEN X = 100 feet per minute x Y
X = 100 feet per minute x 4 square feet
X = 400 cubic feet per minute
This means that a fan capable of pushing 400 cubic feet per minute at 1 inch of static pressure
is needed to yield the optimum air velocity of 1 00 feet per minute. (Note that different filters have
different static pressure ratings and suggested CFM's). In selecting a fan, it is best to choose one that
can deliver more than a 1 00 feet per rriinute air velocity. Install a solid state speed control to regulate the fan as needed.
As the filters become laden with particulafes, the resistance increases and the airflow declines. If

the airflow falls below 20% of the suggested optimum, the 99.99% efficiency rating can not be
guaranteed. Filters of the size in the example above can hold four or more pounds of dust and
spores before needing replacement! With a few hours of use every week (the time most home cultivators spend conducting sterile transfers), the micron filter should last many years, depending of
course, on the ambient spore load in the laboratory.

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