Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Danfoss A/S, Nordborg, Denmark
Fitting for a thermostatic valve
The invention relates to a fitting for a thermostatic valve
comprising a housing with a building-in nipple, as an extension
thereof a cylindrical bore leading to a connector and, between
these, a chamber connected to at least one further connector,
and comprising a valve insert which is for securing to the
building-in nipple, engages in the building in nipple with an
inner portion, carries at an outer portion a coupling device for
securing a thermostat attachment, and is subdivided into a shank
carrier and a seating carrier of which a tube extension is
provided with a sealing head with a circumferential seal for
engaging in the cylindrical bore, particularly for plate radiator
valves.
Such an armature is known from DE-AS 25 27 132. This des-
cribes a thermostatic valve of which the housing is disposed
between two plate radiators and of which the horizontally extend-
ing building-in nippLe terminates within the limits of the
radiators. The shank carrier carrying the closing member is
screwed into the seating carrier. The seating carrier is secured
to the building-in nipple by a coupling nut, projects outwardly
beyond the end of the plate radiators and at this position has
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the coupling device for securing the thermostat attachment. The
coupling nut presses an abutment of the seating carrier against
the end face of the building-in nipple, a seal being interposed,
whereby the axial length of the seating carrier is fixed. The
axial length of the cylindrical bore only slightly exceeds that
of the sealing head of the tubular extension of the seating
carrier. This takes into account any tolerances occurring
during the installation. The use of such a valve insert consist-
ing of a seating carrier and shank carrier has the advantage
that the housing need only be coarsely machined (screwthread,
axial bore) whereas all the components requiring precision
machining are combined in the valve insert. Consequently, the
valve housing can already be welded to the radiator during
manufacture whereas the valve insert is built in only after the
radiators have been installed.
It is also already known to insert the shank carrier directly in
the building-in nipple of the housing and to apply the coupling
device to the housing. However, in this case the valve seat is
in the housing so that fine machining of the housing is indis-
pensable.
It is further known (DE-PS 22 53 462) to separate the seating
carrier from the shank carrier for the purpose of setting the kv
value, a ring carrying the coupling device engaging the building-
in nipple by way of an externaL screwthread and loading the
shank carrier axially, the shank carrier pressing the seating
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carrier against an abutment face provided in the region of the
seat.
In practice, a large number of very different thermostatic
valves is employed. For example, they differ from one another
with regard to the length of the building-in nipple (because the
connections to the plate radiators have a different spacing from
the end of the radiators), with regard to the thermostat attach-
ment (the coupling devices are not standardi~ed) and so on.
Consequently, a particular valve insert is provided for each
application and a corresponding multiplicity of constructions
must be made and held in stock.
The invention is based on the problem of providing a fitting of
the aforementioned kind of which the components are as versatile
as possible to result in large numbers and corresponding manufac-
turing advantages.
This problem is solved according to the invention in that the
separating gap between the shank carrier and seating carrier is
disposed in the inner portion of the valve insert, that the
outer portion carrying the coupling device is formed by the
shank carrier, that the shank carrier is secured to the building-
Ln nipple, that the seating carrier has retaining means within
the building-in nipple for securing its axial building-in length,
and that the axial length of the cylindrical bore is considerably
longer than that of the sealing head.
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In this construction, one and the same valve insert can be
employed for building-in nipples of different lengths because,
for a shorter length, the sealing head simply engages more
deeply in the cylindrical bore. The precise length of bore
depends on what length variations of the building-in nipple
occur in practice. In any case, a single type of seating carrier
can cope with all or a considerable range of these length varia-
tions.
Since the coupling device is carried by the shank carrier, it is
possible to replace or modify the shank carrier for adapting to
different thermostat attachments. This can likewise cover a
large range of variations in the coupling diameter because the
external diameter of the shank carrier can be kept smaller in
the coupling zone than if the coupling device were formed on a
component surrounding the shank carrier.
If the seating carrier is provided with a fixed throttle for
fixing the kv vaiue, a series of seating carriers with different
kv values can be provided without resulting in an excessively
large number of seating carriers to be kept in stock. This ls
because these seating carriers are independent of the length of
the building-in nipple and of the desired thermostat attachment.
In the simplest case, the shank carrier has an external screw-
thread engaging in an internal screwthread of the building-in
nipple. This permits the use of a comparatively small diameter.
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Beyond this screwthread, the shank carrier may have a section of
larger diameter with a circumferential seal held in a groove.
In addition to the sealing function, this can provide a step for
axially fixing the shank carrier.
It is particularly favourable for the shank carrier to be
provided with a securing device for holding the seating carrier
at least temporarily. The shank carrier and seating carrier can
therefore already be assembled before building-in and then
together inserted in the housing. This facilitates assembly.
The securing device of the shank carrier may be an internal
screwthread inta which an external screwthread of the seating
carrier is screwed. This provides a permanent attachment which
can also be utilised for fixing the seating carrier axially.
The securing device of the shank carrier may, however, also be a
circumferential groove in which lugs provided on the seating
carrier engage resiliently. To achieve this resilient movability,
the elasticity of the material will generally suffice but it may
also be obtained by additional axial slots.
It is favourable for the securing device of the shank carrier to
be disposed on the inside of a ring extension which carries the
external screwthread for securing to the building-in nipple.
This gives an axially short construction.
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The retaining device of the seating carrier can be particularly
formed by a circumferential flange which co-operates with an end
face of the shank carrler. For example, with a screwthreaded
attachment of the seating carrier to the shank carrier, the
circumferential flange may define the end position.
In a different embodiment, the circumferential flange can be
pressed by the end face of the shank carrier against a step in
the building-in nipple. This securely holds the seating carrier
axially.
The seating carrier may, as is usual, be of metal. In a parti-
cularly preferred embodiment, however, the seating carrier is of
plastics. Such plastics components can be very economically but
nevertheless precisely manufactured by injection moulding.
There is no danger of over-stressing the plastics material
during operation because only the forces exerted on the seat by
the closing member are transmitted as tensile forces.
In particular, the plastics material may be cold flowing and
annular beads may project on the end faces of the circumferential
flange, This results in secure clamping of the circumferential
flange when the shank carrier is scre~ed in.
The axial length of the cylindrical bore depends on the length
variations of the building-in nipple. In practice, the length
is at least 1.8 times but preferably more than twice the axial
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length of the sealing head. In particular, the cylindrical bore
has a length substantially equal to the height of the chamber in
the housing. The distance of displacement should be equal to at
least half the height of the chamber in the housing. The best
utilisation of space is obtained if the cylindrical bore has a
length substantially equal to the length of the tube extension.
In a preferred embodiment, the outer portion of the shank carrier
has a securing device for applying an adaptor ring carrying the
coupling device. To adapt to a different thermostat attachment,
therefore, it is merely necessary to applv or replace the adaptor
ring. In other respects, the shank carrier may remain unchanged.
This provides considerable rationalization advantages.
It is recommended for the adaptor ring securing device to have
an external screwthread associated with an annular abutment. By
tightening this adaptor ring against the abutment, one obtains a
defined position.
The adaptor ring securing device may be provided axially beyond
a coupling device that is permanently applied to the shank
carrier. The adaptor ring is therefore required for only some
of the applications.
In a preferred ernbodiment, a coupling device permanently applied
to the shank carrier is fortned by a coupling ring which is
mounted for rotation but only slight axial displacement on a
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cylindrical bearing surface of the shank carrier and is provided
with a radial lug for engaging in a radial groove at the end of
the building-in nipple. The rotatable coupling ring may have a
smaller radial thickness than a ring screwed thereon. The
radial lug will then provide the necessary security against
rotation.
In this case it is favourable for the cylindrical bearing surface
to have a flat circumferential groove and for the coupling ring
to be deformed into the circumferential groove at isolated
points. Such deformation at isolated points for the purpose of
axial fixing is simplest to bring about at thinner portions of
the ring such as those produced at the base of axial grooves.
Desirably, the c~lindrical bearing surface has a larger diameter
than the external screwthread of the adaptor ring securing
device and the end of the coupling forms the annular abutment.
This permits simple manufacture of the shank carrier without
having to form the annular abutment on it.
Further, a circumferential groove with a conical side wall can
be provided between the adaptor ring securing device and the
coupling device permanently applied to the shank carrier so as
to axially fix the thermostat attachment.
With particular advantage, the building-in nipple and the end
part of the housing carrying the cylindrical bore are welded
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into a central portion of the housing bounding the chamber. The
building-in nipple and the end part of the housing are therefore
made separately. This is permissible without any machining
being required after welding because the sealing head balances
out most tolerances in the cylindrical bore. aeyond this, it is
merely necessary to use a building-in nipple of different length
without altering the other valve cornponents for adapting to a
particular radlator.
The invention extends to a shank carrier and a seating carrier
having the features necessary for using with the previously
described fitting. These components can be marketed separately
and adapted to a particular application. Nor do the features
for adaptation influence the use of the shank carrier without a
seating carrier, i.e. in conjunction with a valve seat fixed in
the housing. If one adds this use of the shank carrier, one
achieves still larger numbers.
Preferred examples of the invention will now be described in
more detail with reference to the drawing, wherein:
Fig. 1 is a longitudinal section through a first ernbodiment.
Fig. 2 is a longitudinal ~ection through a like embodiment
having a longer building-in nipple.
Fig. 3 is a section through the region of the seat and tube
extension of the seating carrier.
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Fig. 4 is a longitudinal section through the outer part of the
shank carrier with the adaptor ring placed over it, and
Fig. 5 is a plan view of Fig. 4.
The fitting illustrated in F'ig. 1 for a thermostatic valve
comprises a housing 1 having a central portion 2, an end portion
3 and a building-in nipple 4. The housing is extended for
installation between two adjacent plate radiators, the connec-
tions 5 and 6 being welded to an aperture in the front or rear
wall of one of the radiators. A passage 7 in the housing end
portion 3 leads to a supply connector. The building-in nipple 4
is welded to the central portion 2 along a seam 8 and the end
portion 3 along a seam 9. A chamber 10 is then formed in the
interior.
lnto this housing there is inserted a valve insert 11 consisting
primarily of a shank carrier 12 and a seating carrier 13. The
shank carrier 12 carries a closing member 14 with the aid of the
shank lS. The latter is pressed into the open position by a
return spring 16 supported by a step 17 on the shank and a plate
18 on the shank carrier 12. A sealing insert 19 through which a
pin 20 passes is screwed into the free end of the shank carrier.
8y means of this pin, the actuating shank of a thermostat attach-
ment (not shown) can act axially on the vaLve shank 15. The
shank carrier 12 has a cylindrical extension 21 provided with an
external screwthread 22 for engaging an internal screwthread of
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the screw-in nipple 4 and an internal screwthread 24 for co-
operating with an external screwthread 25 of the seating carrier
13. Still further outwardly, there is a section 26 of larger
diameter with a circumferential seal 27 held in a groove. This
section 26 secures the axial position of the shank carrier 12 by
abutment against a step 28 of the screw-in nipple 4.
The seating carrier 13, which is of metal, for example brass,
has a circumferential flange 29 which co-operates with an end
face 30 of the shank carrier 12 and in this way secures the
axial position of the seating carrier 33. Beyond the seat 31, a
tube extension 32 extends into a cylindrical bore 33 in the end
portion 3 of the housing. The tube extension is provided with a
sealing head 34 having a circumferential seal 35.
As a coupling device 36 for securing a thermostat attachment,
there is a coupling ring 37 which has axial grooves 38 on the
outer periphery and which is rotatably held on a cylindrical
bearing surface 39 of the shank carrier 12 as long as the latter
has not yet been built in. It is prevented from dropping off in
that the material of the coupling ring 37 is deformed into a
flat circumferential groove ll1 by means of a pimple or the like
at several positions 40 indicated by an arrow. The coupling
ring is therefore pre~rented from falling off with a slight axial
play. The coupling ring also has a radial lug 42 engaging in a
radial groove 43 at the end of the building-in nipple 4. In
this way, the shank carrier 12 can be screwed into the housing
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but the rotary position of the coupling ring 37 is nevertheless
secured. This coupling ring is preceded by a circumferential
groove 44 with an oblique side wall 45. When a thermostat
attachment has been pushed on to the coupling device 36, a
radially adjustable element of the thermostat attachment can
engage in the circumferential groove 44 and secure the axial
position.
This circumferential groove 44 is preceded by an external screw-
thread 46 having a slightly smaller diameter than the bearing
surface 39. An adaptor ring can be screwed on to this screw-
thread as will hereinafter be described in conjunction with
Figs. 4 and 5.
The example of Fig. Z consists of much the same components as
that of Fig. 1. Accordingly, corresponding parts are indicated
by reference numerals increased by 100. The following are the
essentlal differences. The building-in nipple 104 is longer
than in Fig. 1. Accordingly, the sealing head 134 is no longer
at the lower but at the upper end of the cylindrical bore 133 in
the housing end portion 103. The possible displacement is
substantially equal to half the height of the chamber 10. On
the ~hole, the cylindrical bore 133 may correspond to the height
of the chamber 10.
The seating carrier 113 and thus also the seat 131 are of plas-
tics materlal. It is provided at its outer encl with axial slots
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47 so that the sections 48 therebetween can be flexed inwardly.
They carry cams 1Z4 which can lock in a corresponding circum-
ferential groove 125 of the shank carrier 112. This produces an
at least temporary attachment of the seating carrier to the
shank carrier, as is desirable for installation. The circum-
ferential flange 129 has an annular bead 49 so that, when the
shank carrier 112 is screwed tight in the building-in nipple
1041 this annular bead 49 is pressed against a step SO of the
housing 101, the plastics being partially deformed by cold flow.
The Fig. 3 embodiment illustrates a seating carrier 213 with
seat 231 and closing member 214, the difference from the seating
carrier of Figs. 1 and 2 only being that a throttle bore 51 is
provided concentric to the seat for determining the k value of
the valve. Accordingly, by replacing the seating carrier, one
can select the maximum flow according to the data of the radiator
installation. In the embodiment of Figs. 4 and 5, the shank
carrier 12 of Fig. 1 is merely supplemented by an adaptor ring
52 screwed on to the external screwthread 46. This adaptor ring
is screwed on so far until it strikes the abutment surface 53
formed by the end face of the coupling ring 37. The adaptor
ring 52 has numerous axial grooves 54 at the periphery that are
adapted to a different thermostat attachment than those of the
coupling ring 37. The adaptor ring may of course also have a
different form, for example be provided with an external screw-
thread or a much larger diameter.
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The coupling device 36 can for example be used in conjunction
with a thermostat attachment of the kind known from DE-PS 32 36
371. The coupling device with the adaptor ring 52 can be used
in conjunction with a thermostat attachment according to DE-PS
31 12 138.
With the aid of the fitting as described, a valve housing 101
suitable for the selected radiator can be chosen by the manufac-
turer. Regardless of this, the mechanic installing the radiator
can select a particular make of thermostat attachment as desired
by the customer whilst using much the same components and he can
select a particular kv value according to the data of the
installation. Nevertheless, manipulation is simple because the
shank carrier and seating carrier can together be built-in and
removed.
The tube extension 32 may also have the same or substantially
the same external diameter throughout. In this case, the "seal-
ing head" is merely regarded as the sealing zone around the
circumferential seal 35 which, at most, has three times the
width of the circumferential groove.
The fitting is not restricted to welded housings but can also
be applied to cast housings. It has particular advantages with
plate radiators but may also be employed for other radiators and
for other purposes.
