Westinghouse 5026 User manual

~
~i ~.
CROSS COMPOUND
STEAM DRIVEN
AIR COMPRESSORS
'i.'
INSTRUCTION PAMPHLET
No. 5026
~
JUNE, 1940
~
(SUPERSEDING ISSUE OF NOYEMBEl<. 1937)
t:;
COPYRIGHT. 1940 BY THE
WESTINGHOUSE
AIR' BRAKE COMPANY
PIITSBURGH, PA.. U. S. A.
om=. 1f®

.-
~
CONTENTS
"
TITLE PAGE
Cross Compound Air Compressors. . . . . . . . . . . . . . . . 5
8112" Cross Air 7
Description 9
Old and New Standard Air Compressors ....... , . 15
3
10112" Cross Compound Air Compressor. . . . . . . . .. 17
Operation of Cross Compound Air Compressors. . .. 18
Type "G" Air Filter. . . . . . . . . . . . . . . . . . . . . . . . . . .. 25
No. 54 Air
............................ 26
General Data 30
Installation and Operating Instructions ...... , . . .. 33
Type "F-I-A" Lubrieator ...................... 43
Repair and Road Tests. . . . . . . . . . . . . . . . . . .. 55
Test of Steam End ............ ............ 59
Disorders . . ........ ,......................... 62
Maintenance .................................. 65
Cleaning the Type "Gil Air Filter. . . . . . . . . . . . . . .. 70

~ \./'~'
,
Fig. 1. Front View of the 8Y2u Cross Compound Air Compressor
with "F-I-A" Lubricator and Type "G" Air Filter
4
~
Cross Compound Air Compressors
NOTE-The reference numbers shown herein are for con-
venience only and are not to be used when ordering repair parts.
See Part Catalog giving piece numbers. etc.
It is generally recognized that the duty imposed upon
the locomotive air compressor has very largely increased
from year to year,
but the extent of this increase is more
fully appreciated when the following factors are con-
sidered:-
(a) The development of locomotives of great
weight and tractive power and
in consequence longer
trains
of heavy, large capacity cars.
The large brake cylinders and reservoirs
required for the heavier cars, the longer brake pipe
due to the longer trains hauled, and the greater num-
ber
of flexible connections and fittings where leakage
may occur, combine to demand normally a larger
volume of compressed air than ever before.
(c) The growing use
of many pneumatically
operated auxiliary appliances, such as water scoops,
automatic ash pans, engine reversing appliances,
Pullman water raising system, bell ringers, etc.,
which
take their supply from the air compressor.
(d) The necessity
of avoiding delays at termi-
nals where traffic tends to congest, by a prompt
charging
of long trains. Present day service con-
ditions demand a compressor of ample capacity to
secure maximum brake efficiency.
5

l
(
Fig. 2. Rear View of the 8%/1 Cross Compound Air Compressor
with "F-I-A" Lubricator •
6
SJ;2"
CROSS COMPOUND
AIR COMPRESSORS
The Westinghouse 8%" Cross Compound Compressor
was developed for the specific purpose of combining
maximum capacity and highest efficiency,
by compouna-
ing both the steam supplied and the air compressed to
the extent
that, while this compressor has a capacity
over three times greater
than the well known 9%" single
stage compre3sor, the steam consumption per 100
fpet of air compressed is
but one-third.
The
8%" compressor is supplied in two sizes. The
8%"-150, ordinarily used in steam road service, has a
normal displacement of 150 cubic feet when operating on
200 pounds steam pressure. The
8%"-120 was designed
to operate on a lower steam pressure, and has a normal
displacement of 120 cubic feet when operating on 160
pounds steam pressure.
While the cross compound air compressor was orig-
inally designed to operate on saturated steam
at a
maximum of 200 pounds pressure, the introduction of
superheat steam and higher pressures was later respon-
sible for modifications providing operation on steam
pressures up to
275 pounds.
The present recommended
standard 8%"-150-D air
compressor is suitable for use with both
saturated and
superheat steam up to
300 pounds pressure.
A Special air compressor, known as the
8%"-150-S,
is available for steam pressures up to 400 pounds
pressure.
7

1
!kcl;(ll'l A-A i:A!SfUed
Sectron DD
Rekef Vahe
Fig. 3. Sectional View of Compressor Showing the Present
Standard Piston Type Reversing Valve
Description
As in the case of the standard Westinghouse Single
Stage Air Compressors, the steam cylinders are placed
vertically above the air cylinders and connected by a
common center piece, see exterior views, Figs. 1
and 2.
The sectional assembly view, Fig. 3, serves to illus-
trate the simplicity of this design and emphasize the
the cross compound compressor
is a serial
arrangement of two standard single stage compressors,
actuated by the same controlling mechanism,
and
moving uniformly in opposite directions. This
illustration also the few moving parts employed,
which comprise
(a), the high pressure steam and low
pressure air pistons, connected by a Nickel-Chrome steel
piston rod drilled for the reversing valve rod which oper-
ates the reversing valve,
and which in turn actuates the
main
piHton valve controlling the admission of steam to
and the exhaust from both the high and low pressure
steam cylinders; and
(b), the low pressure steam and
high pressure air pistons connected by a solid Nickel-
Chrome steel piston rod having
no mechanical connection
with the valve gear.
The drain cock
63 is intended to draw off any con-
densation in the steam passage and should always
be
opened when the compressor is first started. The drain
cocks 64, connected to both steam cylinders, are for
the
same purpose and should also be opened for a short time
before the compressor is started
so that any condensation
of steam in the cvlinder
may be removed.
9

10
CROSS COMPOUND AIR COMPRESSORS
•
-----A
i- PIPE FOR DRAIN PIPE
$ECTION TAKEN AT
B·SB.B
FRONT OF
COMPRESSOR
Fig. 4. Views of Center Piece, Showing Drainage and Location
of Oil Hole for High Pressure Air Cylinder
""
DESCRIP'fION 11
Fig. 4 shows partial sectional views of the center
piece of the compressor, illustrating the provision made
for draining
off from the center piece the water which
drips from the stuffing boxes. The water which thus
accumulates
is drained through passages a' and c' to b'
and them~e through the drain pipe connection on the
lower flange to some convenient point, as between the
engine frame.
Fig. 4 also shows the present location
of oil hole for
the high pressure air cylinder. Whereas the oil hole was
formerly located ncar the discharge passage from the
pressure cylinder, an oil hole is now located at a
point where
the oil will feed directly into the inlet pas-
sages to the high pressure air cylinder. The center
is tapped for %-inch pipe on both the front and
back
of the rear wall, thus permitting of attaching the
oil pipe
at either the front or the back. Our standard
practice, however, is to connect the oil pipe
at the front
for the sake
of accessibility, with the back opening
plugged. Interchangeability is not affected in any way
since the old connection
is still
The arrangement of holes, as illustrated, enables the
oil passage in the center piece to
be cleaned out merely
by removing the plug
at the top of the angular hole a
and introducing into it a straight inflexible rod.
Plates 1 and
2, are diagrammatic views in which the
piston valve and reversing valve are turned
90
horizontally from their aetual position in order to make
the operation more easily understood, and all ports and
passages are connected in the simplest possible manner,
without regard to the actual construction
of the com-
pressor.

12
•
eHOSS COMPOUND AIIt COMPHF:SROHH
I' I.";'
Fig. S. Outline of Compressor with Sectional Assembly Views IIf
the Standard Design Main Valve and Housing
~
DESCRIPTION
13
Referring to Plate 1, steam inlet passage a, communi-
cating with cavity K and the two chambers A and A',
conveys the steam from the source of supply to the
operating valves, of which there are two, namely: the
reversing valve 22,
and the piston valve 25. The piston
valve
is a multiple piston device, consisting of a large
piston
at one end, with four smaller intermediate pistons
of uniform size, which will
be referred to hereinafter
as numbers
1, 2, 3, and 4, numbering from the small
piston end of the piston valve.
It is evident, that with five pistons working in a
cylinder,
we have, including the ends, six separate
chambers.
In this particular construction, five of these
chambers have permanent connections as follows:
The first chamber, E, behind the outer end of the
first small piston, to the atmosphere.
The.second chamber
A, between the first and second
pistons, to passage
a.
The third chamber F, between the No.2 and No.3
intermediate pistons, to the lower end of the low pres-
sure steam cylinder (passage
f).
The fourth chamber D, between the No.3 and No.4
intermediate pistons, to the upper end of the low pres-
sure steam cylinder (passage
d).
The fifth chamber A' between the fourth intermediate
and the inner side of large piston, to steam inlet passage
a.
The reversing valve 22 moving vertically, controls
the admission and exhaust of steam from cavity N, be-
hind the outer end of the large piston of the piston valve,
causing it to operate horizontally, the intermediate pis-
tons moving as follows:

15
14 CROSS COMPOUND AIR CuMPRESSORS
Intermediate piston No, 4 crosses a connecting
with passage
c, controlling the flow of steam to the upper
end of the high pressure steam cylinder, and also the ex-
haust into the upper end of the
low pressure steam cyl-
inder,
Intermediate piston No, 3 crosses a port connecting
with passage
e, controlling the exhaust of steam from
either end of the
low pressure steam
Intermediate piston No, 2 crosses a port connecting
with passage
g, causing steam to be admitted to the lower
end of the high pressure steam cylinder or exhausting
steam from this cylinder into the lower end of the low
pressure steam
The recent addition of four grooves to the inner end
of the large main valve bushing
107 (Fig, 5) serves to
prevent possibility of vibration of the main valve when
the compressor
is operating under a very restricted
throttle, Under this condition should the reversing valye
fail to supply
and maintain steam pressure on the outer
of
the large piston equal to that on the inner side,
these by-pass grooves serve
to equalize the pressure on
the large piston before the by-pass grooves in the small
piston cylinder balance the pressures
at that end, The
large piston is thus brought into full balance regardless
of the condition of the reversing valve and related parts,
thereby preventing rebound of the main valve and
vibration,
The piston reversing valve is a multiple
device (similar to the main valve) consisting of four
pistons of the same size except the upper piston which
is slightly smaller (see Fig.
3). A port z through the
piston valve equalizes the pressures
at each end and the
DESCRIPTION
difference in size of the end pistons is such as to com-
pensate for
the weight of the reversing valve and rod so
that these parts are always in balance,
Chamber B between
the two upper pistons is
in communication with the exhaust port e, Chamber K,
between the two lower. pistons is
at all times connected
to the steam inlet passage a, The reversing valve cap
serves as a bush for the upper piston and permits re-
moval of
the reversing valve,
Relief valves
155 (section B-B) and 156, Fig. 3,
which are constructed as shown by the small section
at
the foot of Fig. 3, are for the purpose of preventing ex-
cessive pressure development in the low pressure air
cylinder, due to leakage
past the high pressure or inter-
mediate discharge valves which might otherwise interfere
with normal operation of the compressor.
Old and New Standard Air Compressors
The preceding description applies to the two new
standard
81/2" air compressors which are intended for
use with steam pressures up
to 300 and up to 400 pounds
as already stated. The principal difference between the
present standard and the former standard compressor
steam pressures up to 275 pounds)
is that the new
compressors employ materials suitable for the
steam pressures and temperatures,
and new type top
heads. A piston type reversing valve performs the same
function as the slide valve
type but is subject to less
friction, resulting in less strain
on the reversing valve
rod
and insuring better performance. The main valve
in the new top head is of one piece construction and the
small end piston is
the same size as the intermediate

~
• ~
DESCRIPTION
17
pistons. The use of a bushed cover for the large piston
end, and a flat cover for the small piston end makes
it
possible to apply the main valve without danger of
breaking the rings since all rings can be observed.
The diagrammatic views, Plates 1 and 2, represent
the new
standard compressors but the slide valve revers-
ing valve is shown
by small supplementary views, and
the section
of this pamphlet under "Operation" applies
equally to both the old and the new standard com-
pressors.
lOY2" CROSS COMPOUND AIR COMPRESSOR
The use of compressed air in the industrial field
has been
so widely extended that the 10%" cross com-
pound compressor was developed for this particular
service, where ordinarily, steam is not available
at the
high pressure used in railway braking service, and the
air pressures used are not
so high.
The' 10%" compressor operates on the relatively
Imy
steam pressure of 100 pounds, with a normal displace-
ment of 150 cubic feet
of air at 80 pounds pressure. The
air cylinders are not water jacketed and no intercooler is
required.
In all essential details this compressor follows
the same general design as
that of the 8%" compressor
previously described.
General
data covering the principal dimen::;ions,
weight, etc.,
of the 10%" compressor is given on page 32.
General Instruetions for the installation and care of
10%" compressors in industrial service are eovered by
Fig. 6. Sectional Assembly View of the Old Standard 8%" Air
Compressor with Slide Valve Type Reversing Valve Descriptive Leaflet No. 2341.

OPERATION of C. C. Air Compressors
See Diagrammatic Views, Plates 1 and Z
When the high pressure steam piston 7 has nearly
completed its up stroke, the reversing valve plate
18
comes in contact with the shoulde.r on the reversing rod
21, forcing this rod
to its uppermost position, carrying
with it reversing valve 22, the movement of which, in
turn, not only blanks passage tn, thereby cutting off
means of exhausting steam from chamber N on the face
of
the large piston, but also opens passage n, filling this
with live steam from steam inlet passage
a.
The pressure thus exerted on the face of the large piston
added to the pressure on
the inner side of the small
1, is now greater than the pressure exerted against
the inner side of the large piston, and the piston valve
moves toward the left, or in the direction of chamber
E.
The small end piston cylinder bush is provided with
elongated grooves. These grooves have been considered
for the sake of simplicity as combined into one groove, p.
As the piston valve moves toward the left and uncovers
these grooves, live steam from chamber A by-passes to
chamber E back of the small end piston.
At the instant
these grooves are cut
off by the further movement of the
piston, port a leading to the exhaust is also blanked
which enables the small piston to. compress the steam
in chamber E, thus providing a high cushioning pressure.
This movement of
the main valve piston admits steam,
through passage
c, to the upper end of the high pressure
steam cylinder, starting the high pressure steam piston
18
OPERA'rTON
HI
on its downward stroke. All parts have now assumed the
position shown
in Plate l.
A direct communication is now established where-
by live steam
is supplied through passage a, chamber A',
and passage c to the upper end of the high pressure steam
cylinder, downward the high pressure steam pis-
ton 7 and low pressure air piston
9, which are rigidly
connected by a piston rod. The movement of the
valve to left, as described above, has
g to passage f through chamber F, thus permitting
steam in the lower end of the high pressure steam cyl-
inder to into the lower end of the
low pressure
steam cylinder under piston
8. The latter cylinder being
of materially larger volume
than the former, it will be
seen
that the steam is thereby made to do its work ex-
pansively
in the low pressure steam cylinder. At the
same
time-
(a) the low pressure air piston 9 is compressing
air
in the lower end of the low pressure air cylinder
and forcing same through the intermediate valves
40 and passage ttt into the lower end of the high
pressure air cylinder under piston
10, and-
(b) air at atmospheric pressure is being drawn
into the upper end of the
low pressure cylinder,
through the air strainer, upper inlet opening, and
past inlet valve
37.
It will be observed that the steam exhausted into the
lower end of the low pressure steam cylinder and
the
low pressure air forced into the lower end of the
pressure
air
sides of their pIstons.
results in an
on the lower
The force thus exerted
,.,