The West Virginian. [volume] (Fairmont, W. Va.) 1914-1974, 1922-11-17
CRITICIZE BY W S
sMAYERSPRINTED
IN TRADE PAPER
Increased Demand for Power
l in Glass Industry Shown
e. by Local Man.

by Local Man.
this months issue OF the Glass
Industry, a technical trade journal
devoted primarily TO glass tech
nology, engineering, raw materials
and glass factory equipment and
operation, appears an article on
Modern Glass Factory Equip
ment," written by W. S. Mayors.
mechanical engineer OF the MonoE'
gah Glass Co. Of this city, This is
the second article written by Mr..
Myers for this magazine, the first
hfying been published in the octo-
Der issue OF the journal.
The advent Of pressing and
blowing machines, displacing hand
work, has created a necessity for
numerous, pieces of auxiliary equip
inent such as air compressors,
blowers, vacuum pumps, gas com.
pressors, ETC., and these have great
lYincreased the demand for power, :
says the article.
The air pressure required is
generally under sixty pounds and
the selection and installation OF
compressors for this service usua'
~ present no great difficulties.
fNgh speed single stage com.
prVl tors with short belt motor
drives are favored generally on &C.
Count Of their comparatively low
first cost and small floor space re.
fiuirements, but where steam a:
co1Jtant pressure is available the
Kye2r round, steam driven com.
ptessprs offer some advantages, es.
|snecS ally in cases where the ex.
hakat can be utilized for factory
beeting.
THE demand for compressed air
us usually fluctuatlng, depending
upon the number OF machines at
work, and tho argument for one
large unit in promotion OF eff.
Ancy and continuity OF service
k'does not hold in this case.
AsIn designing compressor lay.
out to supply air to several ma.
cines IL Is good plan to divide
the installation into two or more
units having capacities which are
muitiples Of the requirements OF I
single machine. all being intercon.
nected. For example. In a plant
with eight machines each requiring
$50 cubic feet OF free air minute,
q desirable installation would com.
prise three $50, two 500 and one $50
e -. NJ. comnressors, by which the
demands Of any combination OF the
eight machines can be met.
The combined capacity OF these
SIX compressors is rs per cent
ebpSee the maximum demand and
tltis reserve capacity is usually
AYosth paying for, as with the eight
lfnRchtpes running and no reserve
Apacity ii would be practically. i'm
nossible to maintain constant com.
5tessor service Indefinitely.
Each compressor must have n
reliable automatic unloading device
m order that, although running, It
may pot function as a compressor,
after Z predetermined pressure ha4
been reached. These devices never
femove all the load, and us a rule
bot more than from 30 to so per
cent Of 1t, during the unloaded per.
iods. For this reason, in the inter.
est OF power conservation, It is i'm
portant that the compressor output
Id maintained with but a small ex.
cess over the demand at all times.
In order to reduce the heavy flus.
tnations in the demand for power
due to unloading, 1t Is a good plan
to adjust the unloaders in such 4
manner that one compressor may
take care Of tho fluctuations in dc.
md for air, allowing the others to
operate without unloading.
.fEleetrfc power companies In re-
cent years have acquired the habit
bf placing on their power circuits
instruments which record peak
loads constantly during IS minute
periods, and the highest peak dur.
S1g the month is taken as a basis
sfig1iring the demand charge.
INnssif several compressors with
large oyer-capaclty should happen
totake their loads simultaneously
during one Of these Is minute per.
iods, and this is liable to happeu
after a temporary stoppage of ths
sornpressors, the power 1tfT for the
whole month would be consider.
ably. increased thereby.
In come Of the newer designs
otS compressors the unloading is &c.
tomplished by means OF increasing
SDd decreasing the cylinder clear.
ince automatically by pressure con.
Erol in small steps, thus doing away
With violent fluctuations in power
ieRand,
The intake pipe from each com,
iressor, should lead to a main IN.
axe which extends upward through
he roof in order that clean, Goa,
ir may be obtained. Dust laden
iir from producers, batch hand.
ing machinery and culIet crlshers
must not get into compressor in.
akes.
slns practice most compressorq
ian excess of cylinder oil and
r