Flow regulating valve

A flow regulating valve combines two throttle locations in a valve housing. One throttle location is always so adjusted that a constant differential pressure prevails across the other throttle location. Therefore at that second throttle location the through flow depends only on the degree of opening and not on the differential pressure. A cone of the second throttle location comprises at least two individual portions which are displaceable relative to each other and by the spacing of which the effective cross-section of the throttle location is variable. That provides a through-flow limiting effect which is not in the form of a stroke movement limitation. Therefore the full adjusting range is available for adjusting the flow. This flow regulating valve is suitable for controlling flows of liquids in heating solutions.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates generally to a flow regulating valve, and may be 
applied in particular to a flow regulating valve of the type having a 
first throttle location by means of which a differential pressure across a 
second throttle location can be regulated to a constant value, wherein 
said regulation is effected by means of a hydraulic drive having a 
diaphragm of which one side forms a wall of a first pressure chamber which 
communicates with an inlet chamber of the flow regulating valve and of 
which the second side forms a wall of a second pressure chamber which 
communicates with a chamber behind the second throttle location, wherein 
said diaphragm is connected by way of a rod to a regulating cone which is 
a component of the first throttle location. 
2. Description of the Prior Art 
In heating installations there is a need to regulate flows of liquid. In 
that situation the volume flow should be independent of the prevailing 
differential pressure. In order to perform that function, it is specified 
as for example in "Recknagel, Sprenger, Honmann: Taschenbuch Fur 
Heizung-und Klimatechnik", edition 92/93, page 433, FIG. 223-25, to 
provide a series connection of a pressure-reducing device and a 
quantitative regulator. The pressure-reducing device in that arrangement 
is a valve which nullifies so much pressure that there is a constant 
differential pressure obtained across the quantitative regulator. If that 
is the case, then in the valve used as the quantitative regulator there is 
a defined relationship between the valve position and the through flow. 
The valve used as the quantitative regulator has a given nominal flow 
therethrough, at maximum opening. That maximum through flow is too great 
for many situations of use. For that reason in many cases such 
quantitative regulators have a device for limiting the flow therethrough. 
Through-flow limitation in that case is achieved by a stroke limitation 
action. However, that stroke limitation action only affords a relatively 
small adjustment range, and that is disadvantageous in terms of the 
regulating properties. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a compact flow regulating 
valve which, as a pressure regulating valve, makes the through flow 
independent of the differential pressure so that the through flow is a 
clear function of the degree of opening of the valve, and the through-flow 
limitation is of such a nature that the full adjustment range is retained. 
In accordance with the invention there is provided a flow regulating valve 
comprising: a valve housing; an inlet chamber; a first throttle location, 
including a regulating cone, disposed in the valve housing; a second 
throttle location disposed in the valve housing; a hydraulic drive 
comprising a diaphragm and first and second pressure chambers, the 
diaphragm having a first side which forms a wall of said first pressure 
chamber and a second side which forms a wall of said second pressure 
chamber, said first pressure chamber communicating with said inlet chamber 
and said second pressure chamber communicating with a chamber located 
behind said first throttle location, a differential pressure across said 
first throttle location can be regulated to a constant value, said 
regulation being effected by means of said hydraulic drive; and wherein 
said first throttle location comprises an opening, and a cone which is 
steplessly axially displaceable relative to each other to vary the spacing 
thereof and thereby to vary the effective cross-section of said first 
throttle location. 
Advantageous configurations are set forth in the appendant claims.

In FIG. 1 reference numeral 1 denotes a flow regulating valve through whose 
inlet chamber 2 the flow medium passes into the flow regulating valve 1 
and through whose outlet chamber 3 the flow medium leaves the flow 
regulating valve 1 again, as is also illustrated by arrows. Disposed 
between the inlet chamber 2 and the outlet chamber 3 are two throttle 
locations which are connected in series. A first throttle location is 
formed by a cone 4 which cooperates with a first opening 5 of a 
double-seat cage 6. The cone 4 is movable relative to the double-seat cage 
6, which permits adjustment of the degree of opening of the valve. 
The double-seat cage 6 is fixedly connected to a valve housing 7. At the 
side opposite the first opening 5, the double-seat cage 6 has a second 
opening 8. A regulating cone 9 is movable relative to that opening 8. The 
regulating cone 9 is connected by means of a rod 10 to a diaphragm 11. The 
diaphragm 11 is part of a hydraulic drive 12 which controls the regulating 
cone 9 relative to the opening 8. That control action is made possible by 
virtue of the fact that on one side the intake pressure and on the other 
side the pressure within the double-seat cage 6 act on the diaphragm 11. 
In order to achieve that action, there is a first pressure chamber 13 
which is connected to the inlet chamber 2 by way of a conduit 14. A second 
pressure chamber 15 is connected to the space 18 within the double-seat 
cage 6 by way of a bore 16 in the rod 10 and a transverse bore 17. 
Connected to the valve housing 7 is a guide housing 19 which serves on the 
one hand to guide the regulating cone 9 and which serves on the other hand 
as a support for a regulator spring 20. The regulator spring 20 determines 
the reference value in respect of the differential pressure, the reference 
value being the value to which this device regulates. The force thereof is 
added to that force which the regulating cone 9 applies to the diaphragm 
11. Acting in opposition to that force is the force which results from the 
pressure p1 obtained in the inlet chamber 2. If the pressure p1 in the 
inlet chamber 2 rises, then the pressure in the pressure chamber 13 also 
rises. That rising pressure moves the diaphragm 11 towards the regulator 
spring 20 until once again a force equilibrium prevails. At the same time 
the regulating cone 9 is moved towards the opening 8 by the movement of 
the diaphragm 11 by way of the rod 10 so that the pressure p2 within the 
double-seat cage 8, that is to say, in the chamber 18, rises to the same 
extent as the pressure p1 in the inlet chamber 2. Accordingly the 
differential pressure between the inlet chamber 2 and the chamber 18 
remains constant. 
In that way the pressure across the above-mentioned first throttle location 
which is formed by the cone 4 and the first opening 5 of the double-seat 
cage 6 also remains constant. That means that the adjustment of the degree 
of the opening of the valve becomes independent of differential pressure. 
That first throttle location serves as the actual adjusting member for the 
flow through the valve. In accordance with the embodiment that first 
throttle location is of such a configuration that a limitation of the flow 
is possible without a stroke limitation, so that the full stroke movement 
can always take place, which is advantageous in terms of the regulating 
properties. That is achieved by virtue of the configuration of the cone 4. 
The adjusting member for the through flow comprises that cone 4 which is 
fixed to a valve spindle 21. The flow can be varied in a known manner by 
axial movement of the valve spindle 21. A valve drive of any kind (not 
shown in FIG. 1) serves for that purpose. The valve drive permits a strike 
movement H of the spindle between the two limit positions of "closed" and 
"fully opened". The valve drive is generally continuous so that any 
intermediate positions as between the two limit positions are possible. 
In accordance with the embodiment the cone 4 comprises a first cone portion 
22 which is rigid on the valve spindle 21 and a second cone portion 23 
which can be axially differently positioned relative thereto. The spacing 
between the first cone portion 22 and the second cone portion 23 is 
thereby variable. The way of producing such relative positionability may 
be different. FIG. 1 shows a possible configuration in that respect. In 
that arrangement the valve spindle 21 has a screw thread 24 in that region 
in which the second cone portion 23 is carried thereon. In its internal 
bore the cone portion 23 has a screw thread which matches the screw thread 
24. Fixed in the cone portion 23 is a pin 25 engaging into a guide 26 
which is provided in a post member 27. The post member 27 is fixedly 
connected to the double-seat cage 6. 
This arrangement provides that, upon a rotary movement of the valve spindle 
21, the spacing between the first cone portion 22 and the second cone 
portion 23 is altered. Upon rotation in one direction the spacing is 
increased and upon rotation in the opposite direction the spacing is 
decreased. 
FIGS. 2a and 2b (in which the same reference numerals as in FIG. 1 also 
denote the same components) show different spacings which have been 
produced in that way between the cone portions 22, 23. With the lower cone 
portion 22 which is connected to the valve spindle 21 in the same 
position, the positions of the upper cone portion 23 are different. In 
FIG. 2a the spacing between the two cone portions 22, 23 is large while in 
FIG. 2b it is substantially smaller. It follows there from that, in spite 
of the same spindle position, the flow through the valve is less in the 
case shown in FIG. 2b than in the case shown in FIG. 2a. 
Adjustment of the spacing between the cone portions 22, 23 by a rotary 
movement of the valve spindle 21 is produced (FIG. 1) by virtue of the 
fact that a gear 28 is fixedly connected to the valve spindle 21. A worm 
gear 30 which is fixed on a shaft 29 engages into the teeth of the gear 
28. The shaft 29 is driven either by hand or advantageously by an 
adjusting motor (not shown). Motorisation of the adjustment permits remote 
adjustment. In that way a regulator can produce the adjustment. This is 
advantageous in larger installations if a plurality of flow regulating 
valves are to be controlled. In that way it is possible for example to 
provide for limitation of the volume flow under remote control from a 
central location. That solution affords new options in regard to the 
central control of larger installation. Thus for example a district 
heating installation may influence the maximum limitation of the volume 
flow at the consumers and thus react to particular situations such as 
extremely cold periods or a reduction in output in the district heating 
installation. 
The illustrated flow regulating valve 1 is so designed that when the valve 
drive is not actuated, the valve automatically moves into the limit 
position of "closed". A compression spring 31 serves for that purpose in 
known manner, the compression spring being supported at one end against 
the valve housing 7 and at the other end against a pressure plate 32 
connected to the valve spindle 21. 
For the sake of completeness it should also be mentioned that the 
regulating cone 9 has bore 33 which serves for relief of pressure. The 
force acting on the regulating cone 9 is compensated in known manner by 
that pressure relief effect. 
FIG. 3 shows a flow diagram. The dependency of the flow on the spindle 
strike movement is illustrated by line curves. A first curve A shows the 
flow characteristic when there is a large spacing between the two cone 
portions 22, 23 as illustrated in FIG. 2a and a second curve B shows it 
when there is a smaller spacing as shown in FIG. 2b. 
The nominal flow through the flow regulating valve I is given by the 
largest spacing which can be set in respect of the cone portions 22, 23 
with the stroke movement of the valve spindle 21 which is the greatest 
relative to the closed position. A reduction in the flow, which is 
effective over the entire adjusting range of the valve spindle 21, occurs 
by reducing the spacing of the cone portions 22, 23. 
The full stroke movement of the valve spindle 21 is available both when the 
cone portions 22, 23 are at the largest possible spacing and also at any 
smaller spacing. That provides that the full adjusting range of the valve 
spindle 21, that is to say the full regulating range, is always available. 
Although illustrative embodiments of the invention have been described in 
detail herein with reference to the accompanying drawings, it is to be 
understood that the invention is not limited to those precise embodiments, 
and that various changes and modifications can be effected therein by one 
skilled in the art without departing from the scope and spirit of the 
invention as defined by the appended claims.