Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE OF THE INVENTION
Hydraulic valve
BACKGROU21~ OF THE INVENTION
Field of the Invention
The present invention proceeds from a hydraulic
valve in accordance with the first part of claim 1.
Discussion of Backaround
~ydraulic valves which can release or cut off
the flow of a fluid are known. These valves are
frequently actuated by an electromagnet. An accumulator
ensures that these valves close in the event of failure
of the electric energy. Such a valve has a sealing
point which i~ constructed in accordance with the
particular requirements. An axially movable piston
carries the movable parts of the ~ealing point, while
the fixed parts are let into a housing of the valve.
The fluid of which the flow i~ released or cut off is
under pressure, but this pressure energy is not used as
a rule to actuate the valve, 80 that an additional
energy ~ource i~ further alway~ required.
SUMMARY OF T~ INVENTION
Accordingly, the object of this invention as
typified in the claim~ is to provide a novel solution
to the task of creating a hydraulic valve which
requires no additional energy source.
The advantages achieved by means of the
invention are essentially to be seen in that no
separate line must be built for an additional energy
supply for actuating the valve.
The further embodiments of the invention are
the subject~ of the dependent claiMs.
The invention, it~ further development and the
advantage~ achievable therewith are explained in more
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detail below with reference to the drawing, which
represents only one possible embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention
and many of the attendant advantages thereof will be
readily obtained as the ~ame become~ better understood
by reference to the following detailed description when
considered in connection with the accompanyin~ drawing,
wherein one embodiment of the invention i~ shown.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawing, the single figure
shows a diagrammatic representation of a hydraulic
valve 1, which i8 accommodated in a bipartite housing 2
having an upper part 3 and a lower part 4. The
bipartite hou~ing 2 i9 held together by screws (not
represented), and sealed against escaping fluid at the
separation location by a ~eal 5. Moreover, a ring 6 of
metal, which is constructed a~ a stationary part of a
sealing seat, is fixed between the upper part 3 and
lower part 4. The aseociated movable part is worked as
a ring surface 7 onto the top of a lower piston part 8.
The lower pieton part 8 i~ cylindrically constructed
and slides in a cylindrical bore 9 of the lower part 4
of the housing 2. The lower piston part 8 is guided
tightly by the bore 9. In the region inside the bore 9,
the lower piston part 8 has hydraulic centering grooves
10 distributed on the surface, of which some are
indicated. The lower piston part 8 taper~ ~omewhat
downwards, and a ring surface 11 which i8 constructed
as a movable part of a further sealing seat is worked
onto its lower end. The opposite fixed part of the
sealing seat is designed here as a part of the lower
part 4 of the housing 2. Howe~er, it is also possible
for this purpose to let a special ring into the lower
part 4. This ~ealing seat ~huts off a feed line 12 from
a valve chamber 13 in the interior of the lower part 4.
2042~i3:~
A discharge line 14 leadQ out o~ this valve chamber 13.
Both the feed line 12 and the discharge line 14 are
configured such that pipes can be screwed into them. A~
indicated diagrammatically by an arrow 15, the fluid
then flows in through these pipes when the ring surface
11 lifts from the fixed part of the sealing seat, and
leaves the valve chamber 13 through the discharge line
14 in the direction of an arrow 16.
A cylindrical bore 20, the center axis of which
extends parallel to the center axis of the bore 9, is
provided in the upper part 3 of the housing 2. The bore
20 has a step 21, from which a blind bore 22 having a
smaller diameter than that of the bore 20, but having
the same center axis, is introduced into the upper part
3. Guided in the ~lind bore 22 iB a cylindrically
constructed upper piston part 23, which in the region
of the bore 20 has a flange 24 which i~ guided through
the inner wall of the bore 20, so that the upper piston
part 23 cannot tilt. The end 25 of the upper piston
part 23 that faces the lower piston part 8 is
constructed convexly and bears on a flat surface 26 of
the lower pi~ton part 8. It i8 pressed against the
lower pi~ton part 8 by a plate spring assembly 27 which
is supported, on the one hand, against the atep 21 and,
on the other hand, against a shoulder of the flange 24.
The lower piston part 8 transmits thi~ force to the
sealing seat by means of the ring surface 11, which
shuts off the feed line 12.
The upper piston part 23 has a bore 28 which
connects the residual volume of the blind bore 22 to a
volume 29 below the flange 24. The flange 24 ha~ bores
30 which connect the interior, stressed by the plate
~pring assembly 27, of the bore 20 to the volume 29.
The volume 29 reaches downwards as far as the surface
26 of the lower piston part 23. The volume 29 is
connected via a bore 31, into which a pipe connection
can be screwed, to a di~charge device (not
represented), 80 that gases and residual fluids can be
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removed from the volume 29 in the direction of an arrow
32.
The single figure may be examined in more
detail in order to explain the mode of operation. The
hydraulic valve 1 shown can be u~ed, for example, in a
hydraulic safety and control system for the steam feed
of a turbine. In thiR case, a hydraulic oil, for
example, would be used as the fluid. The valve 1 is
firstly closed, and the oil present in *he feed line 12
under pressure cannot flow. However, the hydraulic
safety and control system is filled with oil via a
bypass (not represented). As a result, the pressure in
the discharge line 14, which leads into the hydraulic
safety and control system, rises with increasing
filling level. As soon as half the nominal operating
pressure has been reached in the valve chamber 13, the
force on the lower piston part 8, which is generated by
the pressure in the valve chamber 13, i~ sufficient in
conjunction with the force generated by the pressure in
the feed line 12 to move the lower piston part 8
upwards against the force of the plate spring assembly
27. The valve 1 opens and, as indicated by the arrows
15 and 16, oil flows under pressure through the valve 1
and feed~ the safety and control system.
During the build-up of pressure in the valve
chamber 13 the lower and upper piston parts 8, 23 are
in the position represented. Oil i8 pressed upwards
through the gap between the lower piston part 8 and the
inner wall of the bore 9 into the volume 29 from where,
as the arrow 32 indicates, it is conducted into a
discharge device. Consequently, this gap may only be
small, because otherwise the oil flowing off would
render a build-up of pressure in the valve chamber 13
impossible.
In the open position of the valve 1, the ring
surface 7 pressed against the ring 6 seals off the flow
of oil into the volume 29. The openinq of the valve l
must take place rapidly, and therefore the blind bore
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22 i~ ventilated through the bore 28 and the bore 20
through the bore 30 into the volume 290 and further
through the bore 31 into the discharge device. Upon
clo~ure of the valve, these bores are correspondingly
aerated, in order to achieve a rapid clo~ing movement
in this way. The surface of the lower piston part 8 i8
provided with centering grooves 10, a~ a re~ult of
which it i~ the case that the lower pi~ton part 8 i~
always well centered in the bore 9 and is therefore
prevented from jamming.
The mounting of the valve 1 i8 facilitated due
to the fact that it can be assembled from two
component~. One component consist~ of the upper part 3
of the hou~ing 2 with the installed upper piston part
23, the plate spring assembly 27 and the ring 6. The
other component consists of the lower part 4 of the
hou~ing 2 with the installed lower piston part 8.
Joining the two components is pos~ible comparatively
e~ily, since there i9 no continuou~ piston to demand a
aomplicated alignment of the two parts of the housing
to a common longitudinal axi~. The convexly constructed
end 25 of the upper piston part 23, and the ~urface 26
of the lower pi~ton part 8 interact perfectly, even if
the particular longitudinal axes are offset with
respect to one another, if they form an angle with
respect to one another, or if both are the case.
Jamming of the valve 1 is excluded in any ca~e. The
upper piston part 23 is guided twice, once in the bore
22 and once via the outside of the flange 24 in the
bore 20, 80 that even here jamming is excluded.
When the valve 1 i~ open, which i~ alway~ the
ca~e in normal operation, oil flows through the valve
chamber 13 into the discharge line 14. This part of the
valve i~ constructed ~uch that this flow process is not
impeded, in particular reductions of the flow cro~q-
section are avoided. If, now, a pressure drop occur~ in
the safety and control system, for example because of a
leak in the form of a pipe fracture, the pres~ure in
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the valve chamber 13 also immediately drops to values
below half the nominal pressure. Consequently, the
force exerted by the plate spring assembly 27 prevails
and immediately closes the valve 1. Feeding of oil via
the feed line 12 i8 interrupted immediately, so that no
oil can be pressed out under pressure from the point of
leakage, 90 that consequential damage can be kept low.
It is particularly advantageous that there is no need
to bring up external energy to actuate the valve 1, so
that it always operates reliably independently of any
possible external energy that is ~ubject to failure.
Obviously, numerous modifications and varia-
tions of the present invention are po~sible in light of
the above teachings. It is therefore to be understood
that within the scope of the appended claims, the
invention may be practiced otherwise than as
speaifically described herein.
