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Патент USA US2136693

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Nov. 15, 1938.
A2,136,693 '
Original Filed OCV’L. l0, 1930 » 2 Sheets-Sheet
iw /M/l;
Nov. 15, 1938;
w. H. KNlsKgRN
Origin'a.;- Filed Oct. 10, 1953
2 Sheets-Sheet 2
f BY-íw
Patented Nov. 15, 1938
Walter H. Kniskern, Petersburg, Va., assignor, by
mesne assignments, to The Solvay Process Com
pany, New York, N. Y., a corporation. of New
Original application October 10, 1930, Serial No..
487,887, now Patent 2,062,095. Divided` and
this application November 1, 1934, Serial No.
4 Claims.
This invention relates to relays and more par
ticularly to relays for control apparatus for main
taining a substantially constant level of liquid
>in a vessel into and from which liquid is intro
duced and discharged. The relay of> the present
invention has been found particularly useful in
. connection with controls for maintaining a sub
stantially constant liquid level in apparatus un
derpressure such, for example, as the intercool
ers, scrubbers and separators utilized in the syn
thesis of ammonia. This application is a divi
sion of my application Serial No. 487,887, filed
October 10,1930, issued as Patent No. 2,062,095,
Nov. 24, i936.
An object of this invention is to provide an
improved relay structure which, while particu
larly applicable to control apparatus for semb
ber and other analogous apparatus, is of general
application. vOther objects and advantages, will
appear from the following detailed description.
In the accompanying drawings forming a part
- of this specification and showing for purposes of
exampliflcation a prefered form of this invention
but without limiting the` claimed invention to
such illustrative instance:
Fig. 1 is a somewhat diagrammatic view partly
in section of control apparatus embodying the
present invention;
(Cl. 121-41)
as in vessel'lß.
'I'he adapter column provides an
indirect connection between weigh bottle I9 and
tower or vessel I0.
If desired, direct connections
between weigh bottle and the gas and liquid
spaces in vessel I0 may be used. The weigh
bottle I9 preferably in the form of a cylinder has
its top connected by flexibles 2l with the top of
the adapter column i6 and its base connected by
flexibles ‘22 with the liquid space in the column
I6. Hence, the level of liquid within the weigh 10
bottle is the same as in the adapter column and
in the vessel I0.
Weigh bottle I9 is pivoted to one end of balance
beam 25. The balance beam may be fulcrumed
on any suitable bearings.
In Fig. 2 a preferred 15
type of suspension is illustrated. This suspenn
sion consists of tensioned spring steel strips l,
one at each side of the balance beam. The bot
tom of each of these strips is clamped between
blocks Ii and 6', which are riveted together, and
the tops between blocks 5 and 5', which are riv
eted together, leaving an intermediate free flex
ible portion 4. Blocks 5 and 6 are suitably se?
cured to standard 3. 'I'he free flexible portion «i
of the strip constitutes the fulcrurn point 28 of 25
the balance beam. This type of suspension is
nearer frictionless than a journal bearing, a ball
bearing or a knife edge bearing and consequently,
Fig. 2 is a fragmentary vertical section partly is preferred. It will be understood, however, that
in elevation of the relay embodying this inven ' other types of bearing may be used. Stops 2l' 30
tion taken in a'plane passing vertically through (Fig. 2) mounted on standard 3 and extending
therelay housing and relay piston, a` portion of over the top of fulcrum >point 28 of the balance
the relay needle and relay piston being broken beam 25 limit the rocking movement of the beam ‘
away as indicated to permit illustration of the
in both directions.
End 29 of the balance beam
apparatus on a somewhat larger scale than would , is provided with an adjustable counterweight 3I. 35
be possible otherwise; and
Fig. 3 is a section through the relay needle
taken in a plane indicated by the line 3--3 of
Variations of liquid level in the vessel I0, it will
be noted, cause corresponding variations of level
in bottle I9, consequently increasing or dimin
Fig. 2.
ishing the effective weight of the bottle andthus
In the drawings referring „to Fig. 1, I0 indicates ' rocking end 29 of the balanceybeam either up 40
the scrubbing tower or other vessel having an wardly or downwardly.
inlet line I I through which liquid under pressure
The relay comprises a relay housing 32 having
or a mixtureI of liquid and gas under pressure
stepped piston 33-34 therein, the stepped piston
passes into the vessel I0. Gas inlet line is indi
being made up of piston 33 and hollow rod 34.
cated by the reference numeral 9 and the'gas The area of the upper surface of the piston 33 45
outlet line by the reference numeral 8. The dis
bears a definite“ ratio to the-area of the lower
charge line I2 leads to the high pressure side I3
surface, usually about one-half. The piston 33
of Valve I4 which controls the flow of liquid from remains stationary within 'the housing 32 only
the vessel. Dotted line I5 in'vessel I0 indicates when the pressure of ñuid in chamber 35 above
the height of the level of liquid it is desired to ~ the piston 33 bears a definite ratio to the pres 50
maintain in the vessel. . Adapter column I6 has
sure in the chamber 36 beneath the piston 33;
its top connected by tube I1 to the gas space
depending on the ratio between the areas of the
in the vessel I0 and` its base connected by tube I8 upper and lower surfaces of the piston. Cham
bers 35 and _36 are supplied with pressure ñuid
to the base of the tower or vessel I0 so that the
level of liquid in the adapter column is the same preferably oil through inlet pipe 31 and inlet 55
» i
oriñce 38 respectively, both communicating with
the pressure fluid supply line 39.
The inlet orifice 38 is preferably made approxi
mately one-half the size of the outlet orifice 43
hereinafter described. A drop in pressure of the
.pressure fluid, oil, entering chamber 38 takes
place due to its flow through the `inlet orifice 38,
and the drop varies as the square of the flow.
'I'he pressure within the chamber 36 is con
10 trolled by relay needle 4| suspended from end 29.
of the balance beam.
The conical pointed end
42 of the relay needle regulates the discharge
through orifice 43 in the chamber 36. With the
needle, in a definite position lwith respect to the
15 discharge orifice, in the embodiment herein dis
closed, so that the discharge orifice is approxi
matelyequal to the inlet orifice, the upward and
downward forces on the piston are in equilibrium
and the piston 33 remains stationary at a definite
20 point in the relay housing intermediate the top
and bottom thereof. Movement of the needle
4| away from the definite position in a down
ward direction causing end 42 to restrict the
discharge through orifice 43 causes pressure to
25 build up in chamber 36 with a consequent upward
movement of piston 33. As soon as the equilibri
um between forces above and below the piston 33
openings permits an increased rate of iiow of
fluid from one side of the dash pot piston to
the other and consequently results in a more
rapid movement of the >stepped piston 33. Con
versely, decreasing the extent of the cross drill
‘openings 59 by moving the collar 6| thereover,
retards >the movement of the stepped piston 33.
Relay needle 4| is connected with balance
>beam 25 by the flexible joint 66 involving bolt
61 threaded into the interior of the top of needle
4| and engaging pin 88 integral with or secured
to the balance beam. A spring 89 is confined in
the housing 10 within the needle 4|, the spring
contacting with the pin 88 and thus providing
a flexible connection between the needle 4| and
the balance beam.
As above indicated, end 42 of the needle is
formed of conical configuration, the cone, when
seated within the discharge orifice completely
closing this orifice. Portion 12‘of the needle
merges into portion 14 of greater diameter which
in turn merges into a portion 15 of greatest
In practice it has been found that the usual
cylindrical needle vibrates in the discharge orifice
in Va manner similar to an organ reed vibrating
in a current of air. Vibrations of the needle
>is restored, the piston stops moving. Conversely
upward movement of relay needle 4| by the up
introduce a disturbing influence inthe opera
tions of the control and interfere with satis
away from the aforesaid definite position causes
factory operation. I have found that vibration
of the needle may be eliminated b-y providing the
an increase in the escape of pressure fluid
needle with extensions or wings, such as are
through orifice 43 with consequent decrease in
pressure in chamber 36 and descent of the piston
shown at 18, Figs. 2 and 3. These wings operate
in a bath of oil maintained below overflow pipe
11. These wings are located as near the point
of the needle as may be convenient and in the
embodiment disclosed are about four inches long
30 ward rocking of end 29 of the balance beam 25
35 33.
The relay piston rod 34 moves in a sleeve
40 positioned within the relay housing 32.
The relay housing 32 and associated elements
are shown in structural detail in Fig. 2. To per
mit a ready assembly` of the hollow piston rod
40 34 and piston 33, a bolt 44 is utilized which makes
and project about one-quarter or three-eighths of
threaded engagement as indicated at 46 ywith
needle provided with the extensions or wings
herein disclosed does not vibrate, the extensions
an inch beyond the cylindrical portion of the „ .
In practice. it has been found that a
the interior of the hollow rod, the small end of
the bolt passing through opening 45 in piston or wings coacting with the fluid and exerting a,
33, and is secured by nut 44’. A dash pot 41 dampening effect.
45 is provided within the hollow piston rod to regu
The orifice-43, it will be noted, consists of al
late the speed of movement of piston 33 and rod ' member provided with a restricted opening 8 I, the
34. The dash pot stem 48 has its end 49 in member resting on shoulders 82 in chamber 16.
threaded engagement with the interior of casing A sleeve 83 extends through opening 84 in cover
50 suitably suspended from an arm 5| bolted or
50 otherwise secured to a support 52 carried by the
85 which secures the aforementioned bearing sup- ,À
yport 40 for the piston rod 34 within the relay
balance beam 25. `Stem 48 is connected to dash _ housing 32. 'I'he sleeve 83 extends the full length
pot piston 53 through ball joint 54, the` ball 55 of chamber 16, has one end brazed to orifice 43
integral'with or secured to rod 48 being held and the other end provided with a collar 86
in-pos|tion in its seat in the dash pot pistonI 53 threaded thereon and accessible from the top of _l
55 by nut 56.
, Íthe housing. -The sleeve extends concentrically
'I'he base of the dash pot piston isprovided about the needle and wings and is of suflicient
lwith a vertical opening 51 which aligns withl the .diameter to,avoid contacting the wings. Sleeve
vertical »channel or opening 58 passing through 83 permits ready removal of the orifice plate 43
ball 55 and the end'of dash pot rod 48. Cross for cleaning or other purposes. A similar sleeve,
d‘rill Vopenings 53 communicate with opening 5_8 construction may be provided in connection with
orifice 38, hereinbefore described, vto permit ready.
. and with the interior of chamber‘54 which pref
erably is filled with oil. A` collar 6| brazed or
removal 'of the orifice.
otherwise secured to a long sleeve 62 concentric
in the sleeve 83, above wings 18, and permit flowv
with the dash pot piston 48 is positioned in the
65 neighborhood of the cross drill openings and
is adaptedrto be moved to cover more or less of
the cross'` drill openings and thus regulate »the
effective> extent of openings 59. Collar 6| is
moved bythe long sleeve‘82, the interior of the
top 63 ofy which is in threaded'engagement with
threads 64 on the dash pot rod 48. . A lock nut
85 maintains the sleeve 82 in adjusted position.
»The long sleeve 82 provides an accessible means
of-regulating the extent of the'rcross drill open
75 ings 59. Increasing the extentof the crossdrlll
Openings 81 are formed
of oil or other pressure fluid through the orificel
43 into chanrber 16 out through the drain pipe 11.
Pivoted to the body of the piston rod 34 as
indicated at 9|, is- one end of a floating lever 92
(Fig. l). ’I'he other end of the floating lever 92
is pivoted, as indicated by the reference numeral
90, to the top of the cam rod stem 93 hereinafter
more fully described. A valve stem 94 is associ
ated with an intermediate point on the floating
lever. The stem 84 passes> through a block 95
integral with or secured to the lever 82. A spring'
88 is coiled abouty the stem 94l and has 'one end 7
contacting with the block 95 and the other en_d
bearing against head 91 of the stem 94. Collar
98 on the stem 94 contacts with block 95 when
of the stepped piston ||1 to force it to the right,
diminishing the valve opening with consequent
decrease in flow from vessel |0 through valve I4
it is moved downwardly, imparting downward
into discharge line |l9.
motion to the stem 94. A relay or pilot valve
|0| involves the usual valve housing |02 and has
the valve spool |03 slidably mounted therein.
Valve stem 94 is connected with spool |03 >through
ball joint |04.
The relay valve is formed with pressure inlet
port |05, which communicates with pressure fluid
supply line |06 in turn connected with pressure
fluid pipe 30. Port |01 in the valve housing com
municates through pipe line |08 with port |09l in
the servo-motor |||. A drain port ||2 in the
base of the relay valve communicates with the
drain line ||3 into which the drain pipe 11 from
the relay-housing also leads. Flange ||4 on the
valve spool is~ of an extent suiiicient to close the
The restoring or compensating mechanism as-`
sociating the servo-motor `| || with the relay to
prevent over-travel of the valve and further to
prevent hunting within the system, will now be
described. The restoring mechanism involves a
cam |25 having a horizontal surface indicated at
|26 and an upwardly inclined surface |21. The
cam is secured to bracket |20 suitably fastened to
stepped piston at |29 so that the bracket |28 and
connected cam reciprocate with the piston | |1.
Guide _roll |3| provided with ñanges between
which the cam moves, provides a guideV and sup
port for the reciprocating cam |25.
A cam follower |33, carried by the cylindrical
stem |34 slidably guided in housing |35 rides
valve port |01 as indicated in Fig. 1. Movement of - on the cam |25. The base of housing |35 is pro
the valve spool downwardly places ports |05 and
|01' into communication resulting in flow ofpres
sure fluid from pipe |03` into ports |05, |01,
vided with vertical slots |36 permitting move
ment of the inclined portion |21 of the cam
therethrough. A rod |31 suitably secured to stem
through pipe |08 into port |09 into the servo
|34 extends therefrom and is pivoted as indi
motor |||. Movement of the valve spool |<03 in ' cated at |38 to the cam rod stem 93. Spring |39
an upward direction places port |01 into com
coiled about stem |31 contacts with the top in
terior of housing |35 and with the cylindrical stern
munication with exhaust port | l2 and causes ex
haust of pressure fluid from servo-motor ||,|
|34 and functions to hold cam roller |33 carried
through port |00, pipe |08, ports |01 and ||2 into by the stem |34 into engagement with the cam
track on cam |25. Movement of the stepped 30
exhaust pipe || 3.
Movement of the valve spool is effected through piston toward the left (Fig. 1) from the position
stem 94 and the floating lever 02 which is in turn indicated occasioned by the valve spool |03 being
moved by the piston rod 34. Thus, when the rod lowered causing pressure fluid to flow through
34 moves up, it rocks the floating lever 92 about ports |05. |01 and |09 into servo-motor, causes
the pivot point 90 and through spring 96 pulls up the cam |25 to move toward the left with a conse
on stem 94, causing the stem and connected valve quent elevation of stem |34, |31 and 03 raising
spool |03 to move upwardly. When the piston the floating lever 92 about pivot point 9|, re
rod 34 descends, it causes downward rocking of storing the valve spool |03 to its original position
lever 92 about the pivot point 90,l moving stem and thus preventing further introduction of pres
90 and the connected valve spool downwardly sure fluid into the servo-motor and consequently 40
through contact of block 95 with the collar 9B. avoiding over-travel of valve sterri ||0 and hunt
As above indicated,.movement of the piston r'od ing within the system. 'I‘he converse of the above
30 up or down is caused by changes of liquid operations takes place when the stepped piston is
level in vessel |0 and weigh bottle i9 which move vmoved to the right.4 Thus the restoring mech-ß
anism prevents over-travel of the valve stem after 05
the relay‘needle 4| to Vary the pressure in cham
each impulse imparted to the weigh bottle which
ber 36 below the piston 33.
The servo-motor | | i is of sufñcient size to exert is in turn transmitted to the relay controlling the
the necessary forces for moving the valve stem operation of the servo-motor.
The valve seat and stem and the shape of the '
||0 in the valve |4 against the high pressure oc-»
curring in chamber i3 of the valve through cam |25 is designed as shown in Fig. l to prevent 50
which the liquid from vessel i0 flows into the low wire drawing in the valve i 4 and to insure prompt
pressure chamber ||6 of the valve |4. The valve opening of the valve from closed position with
stem ||4 is preferably made integral with rod gradual movement of the valve o-nce it is opened.
| |5 which extends Vthrough the low pressure The valve seat is cylindrical as indicated at |4|
chamber | |6 and is suitably secured as indicated and is provided with a conical seating portion
|42. Valve stem_ | Hl‘comprises a conical seating
at ||8 to the stepped piston ||1 of the servo
motor. Discharge line ||9 leads from the low portion |03 adapted to register with and seat in
|42, a cylindrical closing portion |40 of substan
pressure chamber ||6 of the valve to a suitable
point- of disposal for the liquid flowing from the tially the same diameter as |4| and arranged to
vessel i0.
Oil is supplied at constant pressure to the
small end of the stepped piston ||1 of the servo
" motor through inlet port |2| and pipe |22 which
communicates with the supply line 39. The oil
pressure on the small end of the stepped piston
functions to return the piston when‘ oil is ex
hausted from the large end. Admission' of pres
sure fluid to the large end of the serv'oémotor
through port |09 causes the servo-motor pistons
to> move to the left as viewed in Fig. 1, increas
ing the extent of opening of valve I4 and conse
_ouently‘increasing the flow through this valve.
`Contrariwise, the exhaust of pressure fluid from
fthe large end of _the servo-’motor through port
|09 permits the oil pressure on the small end
seat within |0| and a truncated conical portion 60
|45 in line with and extending from the closing
Assuming the valve is in seated
position. it will be noted that the high/pressure
. portion |704.
within chamber |3 acts upon the stem .and main
tains it in seated position. When thev valve stem 65
is moved towards the left (Fig. 1), lthe valve re-mains closed due to the cylindrical portion |00
remaining within ||| and ‘thus iiow through the
valve is prevented until the portion |04 is com
pletely removed from the seat |4|. Continued
movement of the stem causes cylindrical portion
|44 to leave its seat |4| and permits flow through
the valve. Hence the flow through the valve
upon opening same from closed position acts
upon the end of cylindrical portion |44 remote 75
from the seat |43 and wire-drawing on the seats
point indicated by the line l5, corresponding
|42 and |43 is eliminated.
changes of level take place in theadapter column
I8 and weigh bottle I9 which causes return of
the relay needle to position shown in Fig. 1, and
To permit pr^mpt opening of the valve from
closed position, the cam |25 is provided with the
horizontal surface |26. With the valve stem ||4
in seated position, cam roll |33 rests on surface
|20. Initial movement of the stepped piston with
a consequentI` movement of cam |25, causes no
movement of cam stem |35 due to the fact that
10 the cam does not cause an upward movement
ofthe roller |33, and consequently does not re
store the ñoating lever 92 and the valve spool
|03, hence permitting continued flow of. pressure
fluid into the servo-motor and a rapid opening
15 movement of the valve I4. Once the valve is
opened, the position of the parts is as shown in
Fig. 1, cam roller |33 resting on the'base of the
inclined surface |21. Further movement to the
left of the servo-motor piston causes the restor
ing mechanism to operate to prevent overtravel
of the valve stem ||4 and hunting within the
causes the parts of the control apparatus to be
brought back into equilibrium as shown in Fig. 1.
'I'he converse of the above operations takes
place when the level within the vessel |,0 falls
to a point below that indicated by the line I5.
'I'he invention as hereinabove described is em
bodied in a particular form of construction but
it may be variously embodied within the scope
of the following claims.
I claim:
- 1. A relay comprising -a housing provided with 16
an inlet orifice for admission of pressure fluid to
said housing and a discharge orifice for the dis
charge of pressure fiuid from said housing, a pas
sageway for flow therethrough of pressure ñuid
from said discharge oriñce and a relay needle for 20
controlling‘the discharge o_f pressure fluid through
said discharge orifice, said relay needle extending
It will be noted that any motion of the relay through said passageway and having longitudinal
piston 34 is followed by a corresponding motion ` wings on the portion thereof extending through
of the servo-motor piston ||1 and that -for each said passageway to prevent vibration thereof, said
system as above described.
position of the relay piston 34, there is a corre
wings being spaced from the walls of the passage
way to prevent contact therewith.
and consequently a corresponding extent of open-- ,
2. A relay comprising a housing having a piston
ing of the valve I4.
disposed in pressure fluid within said housing and
In operation, assume that all the parts are in provided with an inlet orifice for the admission 30
the position indicated in Fig. 1 and that oil pres
of pressure fluid to said housing and a discharge
sure is being supplied through pressure supply line ~ orifice for the discharge of pressure fluid from
39, and further assume that due to variations in said housing, a conduit for pressure fluid received
-pressure within the vessel |0 or due to an increase
from said discharge orifice, a relay needle for con
in the rate of flow'of liquid into the vessel I0, __ trolling the' discharge of pressure fluid through 35
the level rises to a point above the dotted line said discharge orifice, said relay needle extend
I5. The level correspondingly risesin the adapt
ing through‘said conduit in spaced relation and
er column -|6’and weigh bottle I9 causing the ef
having longitudinal wings positioned radially
fective 'weight of the bottle to increase. This re
thereof on the portion thereof extending through
suits in a downward thrust upon the end 24 of said conduit to prevent vibration of the needle, 4.0
sponding position of the servo-motor piston ||1
the balance beam 25 rocking it about the fulcrum ' the wings being spaced from the Walls of the con
Hence, end 29 of the balance beam and the ' duit to avoid contact therewith.
3. In a relay, a housing, a hollow piston in
said housing, pressure fluid entry ports above and
' consequently diminishing the pressure in cham
below said piston, a discharge oriñce in said hous 45
ber 36. Accordingly, piston 33 descends, pressure v ing, aneedle valve controlling the extent of dis
relay needle 4| _carried thereby is moved upwardly
increasing the discharge through orifice 43 and
ñuid flowing through cross drill openings 59, open
ings 59, 51'into the space beneath the'dash-pot
pistons. By adjusting the position of the collar
charge through said orifice for regulating fluid
pressures on said piston, means on the needle
valve co-acting with the fluid discharged through
6| to regulate the extent of the cross drill open~' ' said orifice to prevent vibration of the needle' 50
ings, the piston 33 is caused to move at the de
sired speed. The downward movement of the
valve and a dash-pot in said hollow piston con
piston rocks the floating lever 92 about pivot point
90, and moves the valve spool through block 95,
collar 98 and stem 94 downwardly, causing port
piston member disposed in said housing and hav
|05 to communicate with port |01. Pressure fluid
flows through ports |05 and |01 from the pressure
supply line 39 into pipe |08, port |09 into the
servo-motor |||, causing the servo-motor piston
||1 to move towards the left and increase the
opening of valve I4, hence increasing the dis
charge from vessel I0 to cause the level ofA liquid
within the vessel to return to the predetermined
point l5. As the stepped piston | |1 moves toward
the left, the cam |25 moves therewith.
-Cam sur- v
face |21 upon movement of cam |25 causes an
upward movement ofthe cam roller `|33 on the
trolling the movement of -said piston.
4. In a relay, a housing, a vertical reciprocable t
ing a hollow stem, a dash-pot in said stem com
prising a dash-pot piston and a dash-pot stem.
the base of said dash-pot piston having an open
ing therein and said dash-pot stem having a cross
drill opening which communicates with the open
ing in said piston, a sleeve mounted on said dash
pot piston stem arranged to control the extent
of cross drill-opening and thus control the flow
of fluid from one side of the dash-pot piston to
the other, said housing having pressure fluid en
try ports above and below said piston member
and also having a discharge orifice, a relay needle
controlling the extent of discharge through said
cam rod stem |31 and 93, causing the floating orifice, said relay needle 'having extensions po
lever 92 to move upwardly about pivot point 9|. sitioned radially thereon near the base portion
70 This returns the valve spool |03 to its closed po . thereof, and vmeans for maintaining fluid in said
sition, preventing further flow~of pressure fluid housingl at a level above the said extensions on
into the servo-motor. . _
the needle.
When the level within the vessel `|0 falls to a
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