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Патент USA US2118248

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May 24, 1938.
G. KEINATH
2,118,248
HYDRAULI C GOVERNOR
Filed Sept. 15, 1956‘
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2,118,248
Patented May 24, 1938
UNITED . STATES
PATENT OFFICE
2,118,248
HYDRAULIC GOVERNOR
Georg Keinath, Berlin-Charlottcnburg, Germany,
assignor ‘to Siemens & Halske, Aktiengescll
schatt, Siemensstadt, near Berlin, Germany, a
corporation voi.’ Germany
Application September 15, 1936, Serial No. 100,876
In Germany September. 28, 1935
-
" 5 Claims. ~<c1. 236-84)
My invention relates to improvements in hy
draulic governors controlled by electric measur
ing instruments.
'
,
It is well-known in the art to maintain an op
5' erating condition, such as a temperature pre
vailing in a furnace, measured with the aid of
electric means at a constant or variable value
by correspondingly adjusting a control member,
for instance, a valve for the supply of the heat
10 ing agent. As a rule, valves with a hydraulic
'drive by compressed air, oil under pressure or the
like lend themselves particularly to a continuous
control.
‘
I
‘
The design of such governors present great dif
35 ?culties, since the regulating power or the torque
of the electric measuring instruments hitherto
employed is not su?icient to control a hydraulic
governor in a sufficiently reliable manner. =' ‘
20
These di?‘iculties. may be removed according to
the invention by associating the movable system
of a differential galvanometer with a hydraulic
control device, one coil of the movable system
being connected in series with ya resistor varying
automatically in accordancewith the condition
of the object to be controlledand the other coil
of the movable system being ‘series-connected
with a resistor serving to adjust the desired vvalue
of control. As coupling member a strip or tape
may be particularly employed which is connect
30 ed, on the one hand, to the movable system of
the differential galvanometer and on the other
hand, to a lever or the like forming the actu
ating part of the hydraulic control device.
In the accompanying drawing is illustrated an
embodiment of my invention in diagrammatic
form, in which Fig. 1 shows the connection of
the electric parts; Fig. 2 the connection of the
differential galvanometer with the hydraulic con
trol device and Fig. 3 a modified form of the elec
40 tric connection according to Fig. 1.
According to Figs. 1 and 2 a diiierential galva
nometer l is employed for the control of a hy
draulic governor system, both coils la. and lb
of the galvanometer being wound in such a man
ner that the winding planes coincide with each
other. The coil system is rotatably mounted in
_ the field of a strong permanent magnet 2.
Each
of the two coils la and lb of the measuring in
strument l is series-connected'with a variable
resistor 3 and 3 respectively lying in two cir
"cuits, connected to a direct-current source 5.
~The resistor 3 serves to continuously check up
I on ‘er respond to the prevailing operating con
dition. If it is the case of controlling ‘a tem
perature, the resistor 3 is designed in the form
v
of a resistance thermometer. The resistor 4
may be regulated by hand and serves to adjust
the desired operating condition to be maintained.
If it is the case of regulating a temperature to
a de?nite constant value the resistor may be ad
justed either by hand to the desired value or by
means of a clockwork, synchronous motor or the
like.
.
Both coils la and lb of the diiierential galva
nometer I produce opposed torques. The in 10
strument operates, consequently, in response to
the di?erence of the ampere turns or in the
case of an equal number of turns of both coils
in response to the difference in the intensity of
current.
In order to secure the zero position an
outer controlling force is necessary which in the
embodiment according to the invention is given
by a spring 6. The spring 6 is connected to a
lever ‘I which is pivotally mounted as indicated
at 8. One end of‘ the lever l is connected to the 20
shaft of the di?erential galvanometer I through
a small tape 9.
At the other end of the lever is
secured a small plate it! which in?uences the
hydraulic control member, for instance, a con
trol throttle fed preferably with compressed air.
The control throttle consists‘ of the casing H,
the throttle l2 and the nozzle l3, the outlet of
which is varied upon the movement of the lever
‘l by the so-called impact plate 10. The control
member II is connected by a hydraulic conduit 30
54 with a valve l6, which forms the actually con
trolling element of the governor system. In this
‘case a variable pressure of the operating ?uid
is created in the space between the throttle l2
and the nozzle l3, the pressure acting on the
diaphragm piston ii of the valve l6 through the
conduit ll, thereby adjusting upon the de?ection
of thelever l the valve in the desired manner.
The spring 6 serves at the same time to secure
the position of the lever ‘I. In the position
shown in Fig. 2 the spring 6 presses the impact
plate ill of the lever '! against the opening-of .
the nozzle H3. The pressure exerted by the op-‘
erating ?uid, particularly compressed air, issu
ing from the nozzle 13 acts in opposite direc 45
tion to the action of the spring 6 and decreases
the control torque acting on the di?erential gal
vanometer I.
The operation of the govemor'according to the
invention as applied‘ to the control of furnace
temperatures is as follows:
It‘ the furnace temperature which is measured
with the aid of the resistance thermometer 3
coincides with the temperature adjusted at the
resistor it, the parts i, 2 and 'i-l? assume the po- '
2,118,248
> 2
sition shown in Fig. 2; the governor is at rest.
If a change in temperature occurs in the‘ fur
nace the currents ?owing in both coils la and
lb of the differential galvanometer differ from
each other, thus causing the coil system to de
?ect. ‘The impact plate I0 'is moved away from
the nozzle l3 or approaches the same, according
to the difference in‘ temperature prevailing in the
furnace, by means of the parts 9, ‘I. The pres
sure of the operating ?uid acting on the valve
I6 is varied and adjusts the valve" in the desired
manner. If necessary, return motion control or
check-back device (not shown) I may be ‘arranged
on the governor in order to prevent an overreg
16
ulation.
‘
Tests have shown that a, sumciently great
torque of the differential galvanometer is avail-.
able already in the case 1of 9. very small change
in temperature so that the control of the tem
20 perature may be effected very accurately. If de
sired, the sensitiveness of- control may also be
still increased by causing the control throttle to
in?uence at ?rst a hydraulic relay through which
the control valve I6 is operated. The control
25 valve l6 varies in this case in a manner well
. known the supply of the heating agent to the
furnace. .
In cases in which the range of the desired
value should be adjusted within relatively wide
30 limits the resistor 4 and, therefore, in the state
of equilibrium of the governor also the resistor 3
varies considerably in accordance with the ad
justed desired value of control. Accordingly,
smaller currents ?ow in both coils la and lb
of the differential galvanometer at high tempera
tures than at lower temperatures. Thereby the
sensitiveness of the governor at high tempera
mum value corresponding to the minimum ad
justment of resistor 4. In case of Fig. 3, the
additional resistor can be so chosen that its maxi
mum resistance is equal to the difference of the
maximum values of’ the two above-mentioned 5
resultant resistances of the two-branch part of
the circuit between the + and —- lines 5.
It then
is possible to attain the result that the resultant
resistance of the three resistors 3, 4 and I1 and
therefore the current vflowing from the + to 10
the '-~ line ‘remains practically constant at all
possible adjustmentsof the resistor 4. The novel
‘governor system is not limited to the temperature
control = but it may be, for instance, also em-_
ployed for controlling a quantity. In this case it 15
‘is only necessary to vary the resistor 3_automat—. -
ically in accordance with the quantity of a liquid,
gas or vsteam.
The desired value of control is
again adjusted at the resistor 4. This instance
shows that the ‘novel governor is also applicable 20
to such cases-in which no direct electrical meas- -
urement of operating magnitudes is involved, but
any operating magnitudes otherwise measured
are reproduced'by an electric resistance. The
governor according to the invention may be also 25
employed for controlling the ratio of two mag
nitudes. For instance, when controlling boilers.
the novel governor may be‘ used for controlling
thequantity of fuel or air for combustion in ac-' cordance with the delivery of steam. In this case 30.
a suitable measuring instrument for the quantity
ofsteam adjusts the resistor 4, whereas a meas-‘
uring instrument for the fuel or the combustion
air adjusts the resistor 3 so that the capacity of .
the furnace may be adapted to the delivery of 35
steam. When controlling a gasmixture both re
sistors 4 and 3 may be, for instance, in?uenced by
tures is impaired in an undue manner, since a ' two quantity or pressure measuring instruments
predetermined maximum current should not be‘
which are connected to both gas supply conduits,
40 exceeded in order to avoid an overstressing of in one of which lies the valve.
40
'
the measuring instrument I.
'
I claim as my invention:_
To remove the above disadvantages it is pref- _
1. In a hydraulic governor system in combina- 7
erable to use for wide ranges of control the con
nection of the coils la and‘ lb of the, differential
galvanometer shown in Fig. 3. In this connec
tion an additional resistance l‘! is provided, the
control member l8 of which is connected to the
control member IQ of the resistor 4 as indicated
in Fig.3 by dotted lines. When adjusting re
50 sistor 4, the resistor l1 thus is adjusted simul
taneously. The resistor l'l lies in the common
current supply circuit leading to the two coils
la and lb so that upon the adjustment of the
control members l8 and IS the resistance of the
55 resistor l‘l varies inversely proportional to the
tion a hydraulic arrangement for effecting a de
sired control, said arrangement having a hydrau
lic actuating member, a differential galvanome
45
ter having its movable two-coil system-operative
ly connected with said, actuating member, an i
electric circuit including a variable resistor se
ries connected with one coil of said movable sys
tem for setting a predetermined value to be 50
maintained by the governor system, and a sec
ond variable resistor series connected with the
other coil of said movable system and disposed
to be varied automatically in accordance with
55
the condition of the object to be controlled.
2. In a hydraulic governor system incombina
tion an operating element governing the condi
tion of the object to be‘ controlled, a device for
resistance of'the resistor 4. The resistor l‘! is
preferably so dimensioned that in the state of
equilibrium of the governor the same current
?ows for all adjustments of the resistor 4, ‘so ‘controlling said operating element, said device
‘to that even at the maximum temperature which being hydraulically connected with said element 60
may be adjusted as'the desired value of control and having an actuating part and means for
also the permissible maximum current ?ows biasing said part so as to maintain a certain po
through the differential galvanometer, thus se
sition, a differential galvanometer having its
curing the desired sensitiveness of control also at movable two-coil system mechanically connected
65 high temperatures. This condition may be ful
with said part for counteracting said biasing
?lled in the following way. The current ?owing means, an electric circuit including a variable
within the circuit between the + and — lines 5 is, resistor series connected with one coil of said.
in case of Fig. 1, dependent upon the resultant movable system for setting a vpredetermined
resistance of the two resistors 3 and 4 of the two value to be maintained by the governor system,
70 interposed branches of this circuit. If the re
and a second variable resistor series connected 70
sistor 4lis adjusted to its maximum value, the with the other coil of said movable system and
resultant resistance of the two branches 3 and 4 disposed to be varied automatically in accord
shows in balanced state of the arrangement a ance with the condition of the object to be con
certain corresponding maximum value. Accord~ trolled.
. »
75 ingly this resultant resistance has a certain mini~
3. In a hydraulic system in combination an 25
231 were
operating element governing the condition of the
object to be controlled, a device for controlling
said element, said device being hydraulically con
nected with said element and having an actuat
ing lever and a spring tending to maintain a
certain position of said lever, a differential gal
vanometer, a tape operatively connecting the
movable two-coil system of said galvanometer
for moving said lever in counteraction to said
10 spring, an electric circuit including a variable
resistor series connected with one coil of said
movable system for setting a predetermined
value to be maintained by the governor system,
and a second variable resistor series connected
15 with the other coil of said movable system and
disposed to be varied automatically in accord
ance with the condition of the object to be con
trolled.
4. In a hydraulic governor system in combina
20 tion a hydraulic arrangement for effecting a de
sired control, said arrangement having a hydrau
lic actuating member, a di?erential galvanome
ter having its movable two-coil system operative
ly connected with said actuating member, an
26 electric circuit including a variable resistor se
ditional resistor arranged in a. common supply
branch of said circuit so as to carry the sum of
the currents ?owing through both coils of said
galvanometer, said additional resistor being vari
able in order to adjust the current which is
biasing said galvanometer in the balanced state
of the governor system.
5. In a hydraulic governor system in combina
tion a hydraulic arrangement for e?'ecting a de
sired control, said arrangement having a hydrau it)
lic actuating member, a diiferential galvanome
ter having its movable two-coil system operative
ly connected with said actuating member, an
electric circuit including a variable resistor se
ries connected with one coil of said movable sys 25
tem for setting a predetermined value to be
maintained by the governor system, a second
variable resistor series connected with the other
coil of said movable system and disposed to be
varied automatically in accordance with the con
dition of the object to be controlled, and an ad
diti‘onal variable resistor arranged in said circuit
so as to carry the sum of the currents ?owing
through both coils of_ said galvanometer, me
, chanical means o'peratively connecting said ad
ditional resistor with said ?rst-mentioned resistor
for simultaneously adjusting these two resistors,
maintained by the governor system, a'second said additional resistor being disposed to vary
variable resistor series connected with the other ‘ its resistance reversely proportioned to the re
30
sistance of said first-mentioned resistor.
30 coil of said movable system and disposed to be
varied automatically in accordance with the con»
ries connected with one coil of said movable sys
tem for setting a predetermined value to be
dition of the object to be controlled, and an ad
GEORG KEINATH. '
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