close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2130458

код для вставки
Patented Sept. 20, 1938
2,139,453
UNi'i‘ED
2,130,458
POWER CONTROL FOR PNEUMATIC CON
VEYER- SYSTEMS
Herman Busch, Long Island City, N. Y., assignor
to Airmatic Systems, Inc, New York, N. Y., a
corpcration of New York
Application February 29, 1936, Serial No. 66,504
Renewed August 1, 1933
15 Claims.
(Cl. 243-15)
This invention relates to power ‘or motive ?uid
controllers for pneumatic conveyer systems and
more particularly to the general type of controll
ers, the purpose of which is to reduce the total
5 amount of motive ?uid or power required to op
erate such systems. An early prior art controller
of this type is disclosed in Patent No. 968,576
granted to Libby on August 30, 1910.
In the Libby type of controller a main motive
l0 ?uid valve opens for aperiod during which trans
mission is accomplished and closes at the end of
the period, remaining closed until transmission
is again desired. During this period of no trans
mission a so called minimum flow of ?uid is
15 maintained in the transmission line by means
such as a by-pass around the main valve. For
accomplishing the opening of the valve at the be
ginning of a transmission period, pneumatic
means, designed to respond to pressure changes
‘30 in the transmission line, opens a port to admit
operating fluid to a motor which in turn opens
the main ,valve. When the main valve reaches
full open position, the pressure responding means
is rendered inoperative whereupon the main valve
termined by leakage of the operating ?uid from
the motor. As the main valve reaches‘ closed
position, the response means is reconditioned or
30
'
Heretofore the construction of a control mech
anism in which the sequence of operation just
described would be carried out with just the right
interval and overlap to assure stable perform
ance of the valve over long periods has been
35 fraught with great dif?culties. A particularly dif
?cult sequence to carry out in the operation of
this mechanism has been to close the main valve
and restore the response mechanism without the
latter responding to the transmission line pres
40 sure existing just prior to the complete closure
of this valve, causing it to be reopened before
complete closure.
The primary object of this invention is to pro
vide a power control apparatus which will carry
0 out sequences of operation required in the Libby
type of valve with certainty and over long periods
of operation without readjustment.
Another object is to provide a means of restor
50 ing the pressure response control valve to re
sponding condition in a manner such that it will
- not respond to reopen the main valve before it
has completely closed.
Another object is to produce a control valve
55 in which a very low minimum flow may be em~
Another object is to produce a control device
employing a very low minimum ?ow and yet
which is very sensitive to-the insertion of articles 6.
to be conveyed which do not completely ?ll the
conveyer line such as loosely ?tting or badly worn
carriers in a carrier system.
Still another object is to provide a control valve
with means for quickly closing the same at the 10
end of its stroke.
A further object is to provide a control valve
with means for increasing its speed of travel dur
ing the latter part of its closing stroke.
A further'object is to produce a control valve 15
which will operate as e?ectively and economical
ly on long lines as so called “carrier closed” valves,
that is, closed by means responding to pressure
variations incident upon carrier discharge.
A still further object is the construction of a 20
control mechanism of the type to which this'in
vention relates ~in which the various operating
parts are so located on the structure as to ‘func
tion in the best manner and at the same time pro
vide a structure which is simple, having few parts, 25
25 closes by movement over a time interval de
restored for the next transmission cycle.
ployed so that the power saving will be increased
to a maximum.
and presenting a pleasing appearance.
These and other objects will be apparent from
the following description taken in connection with
the accompanying drawings in which:
Fig. 1 is diagrammatic view of a single conveyer‘ 30
line showing where the control mechanism is usu
ally placed therein;
Fig. 2 ' is a sectional view showing the parts
when the main valve is in closed position;
Fig. 3 is a sectional view showing the parts in 35
the position they assume when the main valve is
in full open position; and,
-
Fig. 4 is a fragmentary View showing a modi
?ed form.
.
_
While the use of this invention is not necessarily
restricted to conveyer systemsof the pneumatic
carrier type employing a tube through which car
riers are transmitted by the ?ow of an air cur
rent through the line either under pressure or
vacuum, this invention will be described for illustrative purposes as applied to the vacuum type
of pneumatic carrier systems.
Referring now to Fig. 1 of the drawings, that
portion of a pneumatic carrier system pertaining
to a single conveyer line is diagrammatically illustrated. From a central station desk ill dispatch
lines extend out to various substations. A single
line employing a control device comprises a send
ing tube H having a dispatch terminal l2 and a
return tube l3 provided with the usual delivery
‘10
45
50
‘55
2
2,130,458
terminal l4.
From the latter terminal an ex
tension tube l5 passes down through the central
desk l6 and connects with the power control de
vice |6 at what will hereinafter be referred to
as the transmission line side of the device. From
the suction line side of the device |6 a suction tube
|'| connects with the usual suction or header H3
in which a vacuum is continuously maintained by
means of a suitable exhauster, not shown. In
10 other words, the exhauster is the common power
source and the device |‘6 controls the power ex
pended in a single line. A continuous air pas
sage or conduit is formed by the parts enumerated
from the dispatch terminal I2 through the dis
15 patch and return tubes II and I3 and the con
troller I6 to the exhauster.
Referring to Figs. 2 and 3, the controller I6
comprises a casing 2| divided by a septum 22 into
two chambers, 23 and 24. Chamber 23 is in com
munication with the transmission line and cham
ber 24 is in communication with the suction
header. The septum 22 is provided with two
ports, a large port 25 which is controlled by a
main valve 26 and a small port 21 which is con
trolled by an auxiliary valve 28. The auxiliary
valve is opened by a screw threaded stem 29 and
is set normally off its seat to provide a small air
passage through which is maintained acontinu
ous stream of air ?owing from the transmission
30 line. This continuous ?ow of air will be herein
after referred to as the “minimumflow”.
A motor 30 having a housing 3| is provided
at the side of casing 2| for operating the main
valve 26. This motor is comprised of diaphragm
35 32 connected to the main valve by means of a
stem 33 which the motor reciprocates through a
bearing 34 in the inner wall of the motor hous
ing. The housing 3| comprises a saucer shaped
base section 35 and a similar shaped cap 36 at
40 tached to the base with the rim of the diaphragm
32 held between these two elements.
The diaphragm divides the housing into inner
and outer chambers 31 and 38. The inner cham
ber 31 communicates freely with the suction or
45 low pressure chamber 24 through a relatively
large unrestricted opening 39. The chamber 38
communicates with chamber '31 through restrict
ed ports 4| and 42. The size of the opening of
port 4| is regulated by needle valve 43. This port
50 constitutes a continuous leakage connection be
tween chambers 31 and 38 by means of which the
closing time of the main valve is determined as
will hereinafter appear.
The auxiliary port 42 and a connecting passage
55 44 provides a supplementary leakage connection
between these two chambers. The passage 44 ex
tends inwardly of the stem 33 from the outer end
through the. diaphragm 32. This passage is
formed at its outer end to admit a plug 45 which
60 carries a reciprocating valve 46. Several air pas
sage ways 41 extend through the plug to permit
the passage 44 to communicate with the chamber
38 when the valve 46 is open but which are closed
by the valve when it is seated upon the inner face
of the plug. A spring 48 urges the valve toward
seated position.
The valve is opened when its
the outer end of the stem have been omitted.
The port 42 is opened and closed by becoming
covered and uncovered as it moves back and
forth through bearing sleeve 34. The port 42
is positioned along passage 44 at a point such
that during the closing stroke of the valve it will
pass out at the right end of the bearing sleeve
34 at the point in the stroke where it is desired
that increase in closing speed is to begin. This
point may be varied by adjusting the sleeve 34 10
longitudinally in its supporting boss in wall 35.
As already indicated the stem 33 extends
through the main valve 26. At its outer end the
stem is carried in the central opening of a boss
member 52 disposed at what is the rear of the
structure viewed as it is ordinarily installed in
service. This boss, as will presently be described,
forms the base or seat element of a pilot valve
which is employed to condition the mechanism
for proper sequence of operation. The inner face 20
of boss 52 carries a recess in which is seated the
outer end of compression spring 53. The inner
end of the spring is secured to stem 33 and ex
er'ts a force su?icient to hold valve 26 normally
on its seat.
ed according to this invention for experimental
use the shoulder moves out a distance of about
1/8 of an inch or less. At the outer face of plate
55 is secured a disc 51 which surrounds the re
duced portion of the stem. In the normal posi 40
tion of plate 55 this disc is positioned at the outer
end of sleeve 54. When the stem moves outward
ly, the disc is engaged by shoulder 56 moving
plate 55 out a distance corresponding to the
protrusion of the'shoulder portion 56. The outer 45
end of the stem extends beyond disc 51 and car
ries an adjustable collar 58. This collar is set so
that when the main valve 26 is moved to its seat,
the plate 55 is brought against the face of the
boss 52. It will be noted that shoulder 56 and
collar 58 form a lost motion connection between
the stern and plate 55. A spring pressed plunger
56 set in one side of plate 55 bears upon sleeve
54 to form a friction bearing for the plate to pre
vent accidental movement thereof when in its 55
outer position as shown in Fig. 3.
The valve opening movement of motor 36 is
determined by a control valve 6| disposed to nor
mally close a passage 62 leading from atmos
phere (see Fig. 1) through valve seat 63 to cham 60
ber 38. However, it might be spring loaded to
vary gravity action or it might be so positioned
that gravity does not act upon the valve at all.
The valve is lifted by auxiliary motor 64. This
motor comprises a casing which is divided into 65
two chambers 65 and 66 by means of a small
stem 49 engages the inner face of the adjusting
diaphragm 6?, the latter being connected through
screw 5|. Although the supplementary leakage
a suitable operating stem to valve 6|.
The lower chamber 66 is continuously open to
means is shown in stem 33 it could as well be lo
cated elsewhere and the valve 46 operated in ac
cordance with the movements of the motor dia
phragm in some other ‘manner.
.~
7
In Fig. 4 a modi?ed form of the supplementary
leakage connection between chambers 31 and 38
is shown. In this form the valve and plug at
25
The central opening of boss 52 forms a bearing
for the outer end of stem 33 which extends
through a sleeve 54 formed at the outer facing
of the boss. A plate 55 is mounted to recipro
cate upon this sleeve. The outer end of the stem 30
33 is turned down to a smaller diameter to form
shoulder 56 thereupon. When the stem moves
to its extreme left position, the shoulder 56 moves
outwardly beyond the end of sleeve 54 a short
distance as shown in Fig. 3. In valves construct 35
the atmosphere through ports 68. The upper 70
chamber 65 has two passages ‘H and 12 leading
therefrom. The passage 1| connects through
tube 13 with chamber 23 on the transmission line
side of the valve, communicating the pressure in
chamber 23 to chamber 65. Adjustable restric
75
3
2,130,458
tion of this passage is provided by means of screw
14. The other passage 12 is connected by means
of a tube 15, which may be a ?exible hose such as
rubber, and nipple T6 to a recess TI provided in
boss 52. This recess has an atmospheric port
which is preferably faced with a soft resilient
ring 18 which may be live rubber or the like.
The ring is preferably of su?icient thickness to
valve 6| closed cutting off the atmospheric pres
be slightly compressed when plate 55 is brought
in the present case, the speed of the entire closing
stroke is slowed down by the employment of timed 10
closing. When the pilot valve is moved by the
10 into engagement with the face of the boss.
Plate
55 acting as the valve and ring 18 acting as the
valve seat on the atmospheric port form the pilot
valve for opening and closing passage 12 in ac
cordance with the position given to plate 55 by
the movement of'valve stem 33 as already de
scribed. The pilot valve will be designated gen
erally as 19. It is here to be noted that with the
relatively large passage and valve opening, a very
small movement of the valve face plate 55 is re
20 quired to give full opening to the passage. It may
be even less than 1A; inch, already given as the
distance employed in experimental controllers.
Having described the construction of a con
troller embodying the invention, it is believed that
25 a better understanding will be had of how this
invention not only makes such a simple construc
tion and operation thoroughly practical but also
highly desirable by now examining the di?iculties
sure to the main motor. Furthermore it is to be
noted that the full open position is not a critical
one and whether it is completely attained will
not affect the functioning of the valve.
on the other hand, as already pointed out the
primary di?iculties in prior controllers accom
pany the closing stroke, particularly where, as
main valve means, as it approaches the end of
its closing stroke, the main valve is still partly
open and even though the carrier has been dis
charged, su?icient air is passing through the
main valve to keep the pressure at the trans
mission side of the valve considerably below the
minimum flow pressure. It should be noted that,
even though in a decreasing amount, this low or
sub-minimum-flow pressure continues until the
main valve is-closed. And also that the increas
ing restriction upon the passage of atmospheric
air through the pilot takes place reaching com
plete cut-oif as the pilot valve closes.
However,
in these closure movements, as soon as the 25
amount of air entering chamber 55 through pas
sage 72 becomes less than that withdrawn through
passage ll, the pressure in chamber 65 tends
in substantially all arrangements where a por
tion of the main valve movement is employed to
to fall to the sub-minimmn-?ow obtaining on
the transmission side of the main valve. Since 30
the restriction of flow through the pilot valve
varies between full flow and zero flow, and since
provide the movement of the pilot valve, these
dif?culties may be amply illustrated by pointing
the point at which the flow through pilot valve
becomes less than that leaving the auxiliary motor
heretofore encountered.
While the dimculties of
30 simple direct operation of the parts are inherent
35 them out with relation to the type of valve chosen
as the embodiment of this invention. This
means, of course, that for this purpose the auxili
ary leak port 42 with its associated closing ap
paratus and the special form of the pilot valve
are to be considered as absent from the structure.
The operating difficulties grow primarily out of
the inherent characteristics of the main valve of
the prior art controllers to slow down in its travel
as it approaches closed position. This is particu
45 larly true of the double chamber positive action
type of motor where the chambers are separated
by the movable operating wall or diaphragm and
both chambers are normally under reduced pres
sure or vacuum and the forward stroke of the
50 motor takes place upon the controlled admission
of atmosphere or high pressure operating ?uid
to one chamber and the return stroke controlled
in accordance with the resumption of equal pres
sures in both chambers accomplished by means of
55 a controlled leak p-ort between the two chambers.
The falling off of the closing speed at the end
of the stroke is due to the decreased ?ow capacity
of the leak port as the pressures on the opposite
sides of the port approach the point of equaliza
60 tion. This follows the well known laws of ori?ce
?ow.
On the other hand, it should be pointed out
that the main valve is opened by admitting sub
stantially full pressure atmospheric air for the
65 entire opening stroke. Consequently, the main
valve is opened with a relatively quick movement.
Yet, even though the pilot valve when opened
directly must begin to admit atmospheric air to
the operating chamber 65 of auxiliary motor 64
70 before the end of the stroke is reached, the time
required to ?ll chamber 65 with the differential
remainder of air from that admitted over that
withdrawn through passage "H is quite suf?cient
to permit the main valve to reach full open posi
75 tion before the auxiliary motor drops the control
chamber 55 is at some intermediate point of the 35
pilot valve closing, therefore this point will be
reached before. the
valve is entirely closed;
that is while it is still open and while the trans~
mission side is still at sub-minimum-fiow pres
sure. The auxiliary valve does not open, how 40
ever, simultaneously with the reaching of this
point. On account of the reservoir effect of op
erating chamber of the auxiliary valve motor a
moment is required for this “sub” pressure to
accumulate. Now if the response of the auxiliary 45
or control motor is made sensitive, as it must
be if the amount of minimum ?ow is to be kept
low so that a real saving is made by the use of
power controllers, the control valve 6! will be
opened up by the “sub” pressure before the main 50
valve is completely closed, causing it to repeat
edly open and never come to rest at closed posi
tion.
‘
It is to be noted that the relation of the ?ow '
capacity of evacuating passage ‘H and ?lling pas 55
sage l'Z can be modi?ed by an adjustable restric
tion means such as screw ‘it to change the point
at which the “sub” pressure is transferred to the
chamber of the auxiliary motor.‘ However, for
the opening portion of the main valve cycle it is 60
desirable to have the evacuating passage ‘ll rela
tively wide open so that the diiferential build-up
of atmospheric pressure takes place slowly in or
der to permit the main valve to open wide be
fore the control valve closes. On the other hand, 65
for the closing portion of the main valve cycle
it is desirable that the evacuating passage it be
considerably restricted in order to delay the
build-up of the transmission iine pressure. It
will be seen therefore that the adjustments favor
70
ing‘ the two portions of the main valve cycle are
in the opposite direction.
It is primarily because of these difficulties that
a large number of the designs employed for mini
mum ?ow power controllers have proven di?i
75
4
2,130,458
been accomplished primarily by the provision
sion line begins to be reduced and, as the valve
opens, is rapidly reduced by an amount su?i
cient to draw the carrier through the transmis
sion line.
The reduced pressure in the transmission line,
due to the opening wide of valve 26, draws air
of the supplementary leak port 42 opened as the
valve approaches the end of its closing stroke
through passage 'H from the chamber 65 and
would become established to hold the valve 6|
cult of adjustment and maintenance and have
become inefficient and obsolete from the stand
point of practical operation.
These di?iculties have been overcome by valves
constructed according to this invention. It has
thereby overcoming the tendency of the valve
10 to slow down and instead speeding up the travel
during this part of the stroke. By this means
the passages controlling the auxiliary motor may
be set for a median of adjustment, and no di?'i
culties be encountered with a sensitively bal
15 anced control valve and motor. When fast clos
ing of the main valve is provided, it has been
found that the flow capacity of these passages
may be adjusted to favor either the opening or
closing stroke and still employ a sensitive con
20 trol valve with ample margin of stability.
The operation of the controller constructed
according to this invention including the auxil
iary leak port, also the simple form of pilot valve,
and its placement will now be set forth.
When
the system is in operation, chambers 24, 31, and
38 are all subjected to the vacuum pressure in
the suction header l8. This is due to the fact
that when no air is entering chamber 38, ‘an
equalization of pressures in chambers 37 and 38
30 is maintained through the port 4! and these
chambers are in communication with the suction
side of the valve through the large opening 39.
Under normal conditions the valve parts take the
position shown in Fig. 2. The minimum. ?ow of
air through the transmission line takes place
through the by-pass port 21 and is regulated by
valve 28.
As already stated the control Valve SI and its
operating motor '64 are so designed and balanced
40 as to be very sensitive or, in other words, respon
sive to a relatively small vacuum. For the usual
conditions it may be designed to respond to a
vacuum of 3 to 31/2 inches of water. The mini
mum ?ow may then be regulated to a vacuum
45
of from 1 to 2% inches of Water according to
the type of line. At such minimum flow pres
sures it is obvious that the volumetric flow of air
is small and that a real saving in power is ac
complished. Although the minimum ?ow pres
sure is low and the margin of sensitivity of the
control valve small, the control has proven to be
very stable when adapted to widely varying con
ditions and has continued to function as set over
considerable periods of time without readjust
55 ment.
The proper adjustments having been made ac
cording to line conditions, as soon as the head
of a carrier enters the mouth of a terminal, it
blocks the entrance of air to the line.
There
60 upon the air ahead of the carrier is exhausted
through minimum flow opening 21 reducing the
pressure in the transmission line and in cham
bers 23 and 55. As soon as a small pressure re
duction occurs in chamber 65, diaphragm 61 acts
65 to lift the valve SI from its seat admitting a rush
of atmospheric air through the passage 62 into
chamber 33. The rate of entrance of air through
this passage exceeds by a considerable amount
the rate of air leakage through both the leak
70 ports 4! ‘and 42. As the air ?lls chamber 38,
diaphragm 32 and attached stem 33 are forced
quickly to the left, moving main valve 26 to full
open position and pilot valve plate 55 to the po
sition shown in Fig. 3.
As soon as the main
75 valve cracks open, the pressure in the transmis
continuously open but for provisions to admit
air to the chamber through passage 12. How 10
ever, to provide the timed closing of the main
valve, control valve 6| must be closed to cut off
atmospheric airto chamber 38 after the main
valve has opened. This is accomplished by the.
opening of passage '52 by means of the pilot valve 15
:9 provided at the rear of the valve casing. The
pilot valve is opened as the main valve approaches
open position. The valve stem 33 near the end
of its stroke moves the disc 55 slightly to the left
uncovering the port in the bushing ring 18, there 20
by admitting a ?ow of atmospheric air through
the pilot valve to chamber 65. It is to be noted
that due to lost motion connection between stem
33 and plate 55 the latter is not moved until the
very last portion of the opening stroke of the 25
main valve. By providing a restriction in passage
‘it through the medium of screw 14, air entering
chamber 65 will not be exhausted through the
passage into the valve casing as rapidly as it en
ters through passage 12. This differential of ?ow
causes pressure in chamber 65 to rise within a
short lapse of time to substantially atmospheric
and since the pressure below the diaphragm is
also atmospheric, the valve 6| will quickly close,
due to gravity. During the above lapse of time, 85
however, the main valve continues to move to
ward full open position. However, when the
valve ‘6| has dropped upon its seat, and the ad
mission of atmospheric air to chamber 38 has
terminated, the opening movement of the main
valve 26 ceases. It is preferable to so time the
operation of the various elements that the main
valve ceases its opening movement before it
comes against any limiting stop member, thus
giving the effect of cushioned opening.
The atmospheric passage to motor chamber 38
having been closed, the pressures in chambers 31
and 38 begin to equalize and at a rate determined
by the setting of needle valve 43 controlling port
M. As the pressure in chamber 38 drops, spring
53 acts to close the main valve by moving the
stem 33 and parts having connection therewith
toward their normal or closed position.
To offset the tendency of the travel of the main
valve to slow down during the latter part of the
stroke the auxiliary leak port 42 is opened up near
the end of the stroke. The port is opened by the
stem 189 of the leak valve (is striking the inner end
of screw 5! or by the uncovering of the port in
the modi?ed form. The point in the travel of the
main valve 26 and the motor diaphragm 32 at
which the auxiliary port is opened is determined
by the length of the stem 49. This point may be
varied by the interchange of valves of various
stem lengths.
The same effect may be accom
plished by setting the screw 5i (shown in Fig. 3)
40
45
50
55
60
65
in or out.
Any desired characteristic of closure of the
main valve may be had by varying the size and
how capacity of the auxiliary leak port and inter 70
connected passage and by determining the point
in the closing stroke at which the port will be
opened up. These may be chosen as just su?i
cient to overcome the tendency of the valve to
slow down at the end-of the stroke so that the 75
5.
2,130,458
speed of the closing travel' will be substantially
period as if there were no intermediate valve
the same for the entire stroke or they may be
chosen so as to speed up the travel at the end of
the stroke.
In order that the controller may be in readiness
at the end of a transmission cycle for a succeed
closure. While at the same time the cuttingo?
of the air ?ow shortly after carrier delivery is
assured.
art di?iculties, the point at which the‘ pressure
been placed in front or on top, very vulnerable
' It is to be observed that a controller has been
provided with assured operation under all con
ing cycle the auxiliary valve 6! and its motor 64 ditions and having a wide latitude of application
must be restored to its normal condition of sen~ and yet which is simple in structure and marked
sitiveness to a drop of pressure in the transmis“ 1 by an absence of a large number of interlocking
and coacting parts. Further, due to the sim
10 sion line below minimum flow pressure. This .is
accomplished by the main valve during the latter piicity of its operation, it has been possible to
part of its stroke acting to close the pilot valve. shift the pilot valve and its operating parts to the
As already explained in the examination of prior rear of the casing, whereas heretofore they have
15 in the operating chamber 65 of auxiliary motor M
begins to assume the pressure in chamber 23 is
when the air entering chamber 65 through pas
positions for accidental damage to the parts. 15
This arrangement also gives a more pleasing ap
pearance to the eye.
'
sage ‘F2 is restricted by the pilot valve to an
amount less than that leaving through passage
20 ‘H. It was also pointed out that the point at
It is to be understood that the form of the
structure shown is merely illustrative and that
while the invention has been shown in but two 20
forms, it will be apparent to those skilled in the
art that it may be embodied in many other forms
and modi?cations without departing from the
tion with a large aperture seat 78 and large faced
25 valve moving normal to the seat, the restricture
of the ?ow therethrough takes place with a very
small movement of the valve. This would take
place in about one-half or less of the travel given
the valve as shown in Fig. 3.
With a pilot valve having the above character
30
istics combined with the feature of increased
speed of travel of the main valve at the end of the
‘stroke, no dii?culty is experienced with. the aux
iliary motor building up to its condition of sensi
35 tivity to pressures on the transmission side of the
main valve before the latter has completely closed
spirit thereof and it is desired, therefore, that
only such limitations shall be placed thereon as
are imposed by the prior art or by the appended
which this begins is reached before completed
closure of the pilot valve. However, when the
pilot valve is constructed according to this inven
and the transmission line pressure has come up
to the normal minimum ?ow pressure. In this
manner complete closure of the main valve is
40 assured at the end of each cycle and repeated
opening or “pumping” of the valve will not occur
when there is no carrier in the transmission line.
The result of the fast closure of the main valve
is that a simple form of pilot valve may be em
45 ployed and may be operated directly from the
stem of the main valve and yet stable and certain
operation be assured and maintained over long
periods of time.
Fast closing of the main valve enables the tim
50 ing function to be restricted to the ?rst portion
of the stroke or the portion in which the valve
has little or no restrictive effect on the flow of
transmission line motive ?uid. 0n the other
hand, the restrictive portion of the stroke is
55 traversed relatively quickly. This is advantageous
in cases where the carrier is heavily loaded or
worn or, for some other reason does not traverse
the transmission line in the normal period re
quiring two or more time cycles to complete the
60 transmission. In such a case the shortness of
the restrictive travel time of the main valve causes
only a slight hesitation of the carrier instead of
a substantially complete stoppage with its attenci~
ant delay.
These features of the power control give it op
erating characteristics equalling the so called
“carrier closed” valves. It is well recognized that
for short lines time control is adequate, the in
frequent unusual condition being taken care of
70 by a reopening of the valve. On the other hand,
for long lines the valve may be set for two or
more time cycles for the required travel period
of the average carrier and the carrier will travel
with substantially undiminished speed and be
75 delivered in within substantially the same time
25
claims.
What I claim is:
.
1. Power control apparatus of the minimum
?ow type for a pneumatic conveyer line having 30
a transmission line tube and an exhaust line tube
and a main valve between said tubes for con
trolling carrier propelling'airv?ow through the
line, means for establishing a minimum ?ow of
air through the line when the main valve is closed,
means for opening the main valve in response to ’
the presence of a carrier in the transmission line,
and time controlled means for closing the valve,
said response means including a pneumatic with
a diaphragm constantly exposed on one side to 5.1.0
atmospheric pressure and means for sensitizing
it to the presence of a carrier in the transmission
line by normally exposing its other side to trans
mission line pressure, and means for desensitiz
ing said diaphragm after a response including 45
means for establishing atmospheric pressure on '
said other side of the diaphragm at the
opening stroke of the main valve and
ing the said pressure until the end of
closing stroke of said valve.
2. Power control apparatus of the
end of the
maintain
the timed
minimum
?ow type for a pneumatic conveyer line having a
transmission line tube and an exhaust line tube
50
and a main valve between said tubes for con
trolling carrier propelling air flow through the 55
line, means for establishing a minimum ?ow of
air through the line when the main valve is
closed, means for opening the main valve in
response to the presence of a carrier in the trans
mission line, and means for closing the valve 60
after a period of time has elapsed, said response
means including a pneumatic with a diaphragm
continuously exposed on one side to aconstant
pressure, means for sensitizing it to the presence
f a carrier in the transmission line by normally
exposing its other side to transmission line pres- '
sure, and means for desensitizing said diaphragm
after a response including means for establishing
a pressure equal to said constant pressure on
the other side of the diaphragm at the end of the .70
opening stroke of the main valve and maintain
ing said pressure until the end of the timed clos
ing stroke of said valve.
3. Power control apparatus for pneumatic con
veyer lines of the vacuum minimum ?ow type 7.5
6
2,130,458
having a transmission line tube and an exhaust
line tube and a main valve between said tubes
for controlling carrier propelling air ?ow through
the line, means for establishing a minimum ?ow
of air through the line when the main valve is
closed, a main pneumatic for opening the main
valve, an auxiliary pneumatic embodying a con
trol valve for initiating the opening and closing
action of the main pneumatic and a diaphragm
for operating the control valve, said diaphragm
and valve being biased toward the normal posi
tion of the valve, one side of said diaphragm
being constantly exposed to atmospheric pres
sure, means for normally exposing the other side
to transmission line pressure, said control valve
being arranged so that a pressure drop due to
the presence of a carrier in said line operates the
control valve to cause said main valve to open,
and means operated by movement of said main
20 valve for establishing atmospheric pressure on
said other side of the diaphragm at the end of
the opening stroke of the main valve for equaliz
ing the pressures on opposite sides of said dia
phragm so that said bias means will restore the
25 control valve to normal position and cause the
main valve to close.
4. Power control apparatus of the minimum
‘ ?ow type for a pneumatic conveyer line having
a transmission line tube and an exhaust line tube
30 and a main valve between said tubes for con
trolling carrier propelling air ?ow through the
line, means for establishing a minimum flow of
air through the line when the main valve is
closed, a main pneumatic for opening the main
35 valve and including means for timing the closing
of the valve, an auxiliary valve for controlling
the operating ?uid ?ow to the main pneumatic,
an auxiliary pneumatic comprising two chambers
separated by a diaphragm movable to operate
40 said auxiliary valve, one of said chambers being
constantly open to the atmosphere, ?rst and sec
ond passages leading to the other chamber, the
?rst passage being in constant communication
with the transmission line, the second passage
45 being normally closed, and means for opening
the second to atmosphere at the end of the open
ing stroke of the main valve and for closing the
same at the end of its closing stroke.
5. Power control apparatus of the minimum
?ow
type for a pneumatic conveyer line having a
50
transmission line tube and an exhaust line tube
and a main valve between said tubes for control
ling carrier propelling, air?ow through the line,
means for establishing a minimum flow. of air
55 through the line when the main valve is closed,
a main pneumatic for opening the main valve
and including means for timing the closing of the
valve, an auxiliary valve for controlling the oper
ating ?uid flow to the main pneumatic, an aux
60 iliary pneumatic comprising two chambers sep
arated by a diaphragm movable to operate said
auxiliary valve, one of said chambers being con
stantly open to the atmosphere, ?rst and second
passages leading to the other chamber, the ?rst
65 having a determined flow area, the second hav
ing a flow area larger than the ?rst, the ?rst
passage being in constant communication with
to hold said valve closed, a ?uid motor arranged
to open the valve against the action of said resil
ient means; said motor comprising a housing em
bodying a motive ?uid chamber having a movable
side wall and means for operatively connecting
said wall and the valve, a controlled inlet port
for admitting motive ?uid to said chamber for
opening the valve, a continuously open regulata
ble leak port for bleeding the motive ?uid out of
said chamber at a determined rate for permitting
the valve to close, a valve closed leak port and
a rod reciprocated by the movement of the main
valve for opening said port valve as the main
valve approaches closed position to increase the
determined leakage rate and closing the valve at 15
increased speed, and an adjustable stop for the
rod for determining the point in the closing stroke
of the main valve at which the pOrt valve opens.
7. In a power controlling apparatus for a
pneumatic conveyer line, a pneumatic motor hav 20
ing a chamber provided with a movable wall, a
stem extending from said wall to said valve for
operating the latter, a normally closed control
valve in said stem arranged to provide a vent
to said chamber for modifying the operation of
said motor, and means operative by the inward
movement of said wall and stem for opening said
control valve.
8. In a power control apparatus for a pneu
matic conveyer line, a main valve for controlling
the flow of motive ?uid in the line, means for
opening and closing the main valve, an auxiliary
valve for controlling the main valve, a pilot valve,
opened and closed in accordance with the move
ments of the main valve, for conditioning the
auxiliary valve, means for increasing the speed of
travel of the main Valve as it approaches the
end of its closing stroke, and means operated
by the main valve for causing the pilot valve to
be closed in accordance with the modi?ed move
ment of the main valve.
9. Power control apparatus for a pneumatic
conveyer line having a main valve for controlling
the line ?uid ?ow, meansfor opening and clos
ing the main valve, a diaphragm normally sensi 45
tive to the pressure incident to the introduction
of a carrier in the line for controlling the main
valve opening means, a chamber enclosing one
side of the diaphragm, means providing a pilot
port in communication with said chamber for 50
controlling the sensitivity of said diaphragm,
means operated in accordance with the opening
movement of the main valve at the end of its
opening stroke for opening said port and desensi
tizing said control diaphragm, and means acting 55
at the end of the main valve closing stroke in
cluding the portion in which the pilot port is
closed to import a relatively quick movement to
the main valve while the pilot port valve is being
closed.
’
60
10. In a power control apparatus for a pneu
matic conveyer line, a control valve disposed to
travel between extreme open and closed positions
for releasing and restraining the flow of motive
fluid in the conveyer line, said valve being ar 65
ranged so that in a ?rst portion of its travel,
which lies between an intermediate position and
said open position, substantially no restraining
e?ect of the fluid ?ow occurs, while in a second
portion’ of its travel, which lies between said 70
the transmission line, the second passage being
normally closed, and means for opening the sec
70 ond to atmosphere at the end of the opening
stroke of the main valve and for closing the
same at the end of its closing stroke.
6. In combination, a valve for controlling the
flow of motive ?uid through a pneumatic con
a motor having a motive ?uid chamber including
a wall movable between extreme positions by mo
75 veyer line or the like. a resilient means tending
tive ?uid, means for coupling the wall and the 75
intermediate position and said closed position,
substantially all of the restraining e?ect occurs,
7
2,130,458
valve for moving the valve through its travel,
said chamber being provided with regulated ports
for the escape of the motive ?uid for timing the
closing of the valve, one of said ports being open
a regulated amount throughout the closing stroke
of the valve, an auxiliary valve for opening and
closing another of said ports for speeding up the
closing travel of the main valve, means for open
ing said auxiliary valve during the latter part of
10 the closing stroke of said main valve, said valve
opening means being adjustable so that the open~
ing of the auxiliary may be regulated to include
said second portion of its closing travel.
13. In a power control for a pneumatic con
veyer line having a housing, a main pneumatic,
a reciprocating stem extending therefrom and
protruding through one side of the housing, a ,
sleeve extending from said housing parallel with
the protruding portion of the stem, a disk pilot
valve surrounding the sleeve, lost motion‘con
a valve casing being interposed therebetween, a
nections between the stem and the pilot valve for
giving a limited movement to the valve along the
sleeve, a pilot port eccentric of said sleeve and 10
arranged to be covered by the face of said disk
at one extreme position of the valve; and means
for providing frictional engagement between the
pilot valve and the sleeve for restricting the
movement of the valve to that‘ imparted to it
through said lost motion connections.
motor for operating the valve and a controller
therefor carried by the casing, a pilot valve for
14. In a power control apparatus for a pneu
matic conveyer line, a motive ?uid power source,
conditioning the controller, said pilot valve being
a valve casing being interposed therebetween, a
motor for operating the valve and a controller 20
therefor carried by the casing, a pilot valve for
11. In a power control apparatus for a pneu
15 matic conveyer line, a motive ?uid power source,
embodied in a boss disposed at the rear of the
casing and carrying a rearwardly extending
sleeve, said boss having a port formed in its outer
face and arranged to provide the seat portion of
the pilot valve, a disc ?tted to reciprocate upon
25 said sleeve, the inner face of said disc being ar
ranged to form the pilot valve face and acting
when brought against the outer face of the boss
to close said port by seating upon'the rim of the
same, and a lost motion connection between said
conditioning the controller, said pilot valve being
embodied in a boss disposed at the rear of said
casing and carrying a rearwardly extending
sleeve, said boss having a port formed in its outer
face, said port having a rim of resilient material
and arranged to provide the seat portion of the
pilot valve, a disc ?tted to reciprocate upon said ~
sleeve, the inner face of said disc being arranged 1
30 disc and said motor for operating the pilot valve.
12. In a power control apparatus for a pneu
to form the pilot valve face and acting when 30
brought against the outer face of the boss to close
matic conveyer line, a motive ?uid power source,
a valve casing being interposed therebetween, a
motor for operating the valve and a controller
35 therefor carried by the casing, a pilot valve for
said port by seating upon and slightly compres-v
sing the material forming the rim of the same,
conditioning the controller, said pilot valve be
and a lost motion connection between said disc
and said motor for operating the‘ pilot valve.
ing embodied in a boss disposed at the rear of
veyer line having a housing, a, main pneumatic,
said casing and carrying a rearwardly extending
sleeve, said boss having a port formed in its outer
40 face and arranged to provide the seat portion of
the pilot valve, a disc being arranged to form the
pilot valve face and acting when brought against
the outer face of the boss to close said port by
a'reciprocating stem extending therefrom and
seating upon the rim of the same, a lost motion
connection between said disc and said motor for
operating the pilot valve, and means for apply
ing a restraining friction between the disc and
sleeve for guarding against untimely movement
of the disc.
35
15. In a power control for a pneumatic con
protruding through one side of the housing, a
sleeve surrounding the protruding portion of the 40
stem, a pilot valve surrounding the sleeve and
arranged to slide thereupon, means to set up fric
tional resistance to the sliding of said valve upon
said sleeve for holding the valve in slid position
and lost motion connections between the stem and 45
the pilot valve for sliding the latter upon said
SIGGVE.
'
HERMAN BUSCH.
Документ
Категория
Без категории
Просмотров
0
Размер файла
1 262 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа