Refrigeration and Air Conditioning Technology 8th Edition Tomczyk Solutions Manual
Refrigeration and Air Conditioning Technology 8th Edition Tomczyk Solutions Manual
Refrigeration and Air Conditioning Technology 8th Edition Tomczyk Solutions Manual
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part. 3
4 Unit 2
V1 V2 UNIT 2 ANSWERS TO REVIEW TEST
29. The pressure is constant so .
T1 T2 QUESTIONS (lAB MANUAl)
V1 T
2
V
2
1. C. 5. D. 8. C. 11. D.
T1
2. A. 6. A. 9. C. 12. D.
3. B. 7. D. 10. D. 13. C.
(3000 ft3 )(55 460)°R 4. C.
V2 2887.8 ft3
(75 460)°R
PV
1 1 P2 V2
30.
T1 T2
PV
1 1T2
P2
T1V2
(10 psig 14.696) (10.5 in3 )(180° 460)°R
P2 COMPlETED ChART FROM EXERCISE 2-1
(65 460)°R(1.5 in3 )
Line P1 V1 T1 P2 V2 T2
3 3
1 50 psig 20 ft 100°F (25 psia) 50 ft 80°F
3 3
2 50 psia 2,000 ft 75°F 50 psia (2291 ft ) 130°F
3 3
3 40 psia 30 in 80°F 50 psia (24 ft ) 80°F
3 3
4 (100 psia) 20 ft 500 R 200 psia 12 ft 600 R
3 3
5 100 psia 10 ft 600 R 100 psia 25 ft (1500 R)
6 80 psia (150 ft3) 400 R 150 psia 100 ft 3
500 R
7 150 psia 100 ft3 (700 R) 300 psia 50 ft3 700 R
3 3
8 80 psia 500 ft 600 R (160 psia) 100 ft 240 R
© 2017 Cengage Learning®. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
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Papuan Blacksmiths.
But to be a blacksmith in ever so rude and humble a way, certain
tools are absolutely necessary; the ambitious one must have a fire, a
hammer, an anvil, and last, though most important of all, a pair of
bellows. A fire he has; for a hammer his old stone-headed club does
service; a handy bit of rock serves as an anvil; it is the bellows which
is the toughest obstacle; and there can be little doubt that many a
grand notion of blacksmithery has been nipped in the bud because
of the projector’s inability to find anything animate or inanimate of so
accommodating a nature as to hold and husband for his
convenience so slippery a thing as the wind. Wonderful are the
devices resorted to, all however more or less tedious and imperfect;
of all sorts and sizes, from the bottle-like bag which the blacksmith
holds under his arm, extracting therefrom a feeble blast as a
Highlander manufactures bag-pipe music, to the elaborate machine
in vogue in certain parts of Polynesia. Take that used by the
Papuans as an example. Here we find two hollow pillars of wood
fixed close together and furnished within a foot of the ground with a
connecting pipe terminating in a nozzle. The interior of the pillars are
perfectly smooth and furnished each with a “sucker” consisting of a
sort of mop of finely-shredded bark; squatting on the top of these
pillars the bellows-blower takes the mop-handles in hand and works
them up and down, causing a tolerably strong and regular blast to
emit from the nozzle.
It is related by the missionary Ellis, that King Pomare entering one
day the shed where an European blacksmith was employed, after
gazing a few minutes at the work, was so transported at what he saw
that he caught up the smith in his arms and, unmindful of the dirt and
perspiration inseparable from his occupation, most cordially
embraced him, and saluted him according to the custom of the
country by touching noses.
Le Vaillant, while travelling in Southern Africa, on one occasion
saw a number of Caffres collected at the bottom of a rocky
eminence, round a huge fire, and drawing from it a pretty large bar of
iron red-hot. Having placed it on the anvil they began to beat it with
stones exceedingly hard and of a shape which rendered them easy
to be managed by the hand. They seemed to perform their work with
much dexterity. But what appeared most extraordinary was their
bellows, which was composed of a sheepskin properly stripped off
and well sewed. Those parts that covered the four feet had been cut
off, and placed in the orifice of the neck was the mouth of a gun-
barrel around which the skin was drawn together and carefully
fastened. The person who used this instrument, holding the pipe to
the fire with one hand, pushed forwards and drew back the extremity
of the skin with the other, and though this fatiguing method did not
always give sufficient intensity to the fire to heat the iron, yet these
poor Cyclops, acquainted with no other means, were never
discouraged. Le Vaillant had great difficulty to make them
comprehend how much superior the bellows of European forges
were to their invention, and being persuaded that the little they might
catch of his explanation would be of no real advantage to them,
resolved to add example to precept and to operate himself in their
presence. Having dispatched one of his people to the camp with
orders to bring the bottoms of two boxes, a piece of a summer kross,
a hoop, a few small nails, a hammer, a saw, and some other tools,
as soon as he returned our traveller formed in a very rude manner a
pair of bellows about as powerful as those generally used in
kitchens. Two pieces of hoop placed in the inside served to keep the
skin always at an equal distance, and a hole made in the under part
gave a readier admittance to the air, a simple method of which they
had no conception, and for want of which they were obliged to waste
a great deal of time in filling their sheepskin. Le Vaillant had no iron
pipe; but as he only meant to make a model he fixed to the extremity
a toothpick case after sawing off one of its ends. He then placed the
instrument on the ground near the fire, and having fixed a forked
stick in the ground, laid across it a kind of lever, which was fastened
to a bit of packthread proceeding from the bellows, and to which was
fixed a piece of lead weighing seven or eight pounds. The Caffres
with great attention beheld all these operations, and evinced the
utmost anxiety to discover what would be the result; but they could
not restrain their acclamations when they saw our traveller by a few
easy motions and with one hand give their fire the greatest activity
by the velocity with which he made his machine draw in and again
force out the air. Putting some pieces of iron into the fire he made
them in a few minutes red-hot which they undoubtedly could not
have done in half an hour. This specimen of his skill raised their
astonishment to the highest pitch: they were almost convulsed and
thrown into a delirium. They danced and capered around the
bellows, each tried them in turn, and they clapped their hands the
better to testify their joy. They begged him to make them a present of
this wonderful machine and seemed to wait for his answer with
impatience, not imagining that he would readily give up so valuable a
piece of furniture. To their extreme satisfaction he granted their
request, and they undoubtedly yet preserve a remembrance of that
stranger who first supplied them with the most essential instrument
of metallurgy.
PART X
INCIDENTS OF PERSONAL PERIL AND DISCOMFORT OF TRAVELLERS AND
EXPLORERS.
CHAPTER XXV.
A night’s lodging at Brass—Delightful bedfellows—Sleeping out on the
Gambia—“Voices of the Night”—Lodging “up a tree”—Half a cigar
for supper—The “leafy couch” abandoned—The bright side of the
picture—Dr. Livingstone no washerwoman—An alarming
“camping out” incident—The terrible tsetse—The camp in the
wilderness—The privileges and perquisites of a Pagazi—No
finery worn on the road—Recreation on the march—Daily life of
an Eastern African—His sports and pastimes—Approaching a
cannibal shore.