Note: Descriptions are shown in the official language in which they were submitted.
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A WATER-METERING INSTALLATION PROTECTED AGAINST FROST
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a water-
meterinq installation which is protected against frost
hazards.
Description of the Prior Art
In water-metering installations, the water
meter is connected to a water inlet pipe and to a water
outlet pipe which are buried in the ground.
The water meter is located either above ground
level or within a well, the well being preferably closed
at the top by a removable cover-plate which serves to
gain access to the meter.
In the first case, that is to say when the
meter is above ground level, it can be protected
externally by a box-type housing or enclosure which also
makes it possible to gain access to the meter.
In all cases, it is necessary to protect the
meter and the water inlet and outlet pipes against frost
hazards.
To this end, various techniques have been
proposed.
In accordance with one of these techniques, it
has been proposed to protect the water pipes connected
to the meter by means of heat pipes buried in the ground
and put in a condition of heat exchange with the water
pipes.
In accordance with another known technique, it
has been proposed to line the interior of the well in
which the water pipes extend as well as the interior of
the enclosure in which the meter is located with
elements of insulating material such as expanded
polystyrene or polyurethane foam.
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~ owever, the practical use of these frostprotection means is complicated and consequently costly.
Moreover, in these known designs, thermal
bridges remain between the meter and the exterior, with
the result that total frost protection is not ensured.
French patent No. 8~ 03453 in the name of the
present Applicant describes a water meter pivotally
mounted on a base having two waterways connected
respectively to the water inlet and outlet pipes.
By virtue of this arrangement, opening and
closing of the water inlet are controlled by rotating
the meter with respect to the base in order to bring
the waterways of the base in or out of register with
those of the meter.
An installation of this type is particularly
convenient to use but nevertheless gives rise to
problems of protection against frost as mentioned above.
The object of the present invention is to
overcome the disadvantages of known designs by proposing
a water-metering installation which is both convenient
to use, easy to install in the ground and efficiently
protected against frost hazards.
SUMMARY OF THE INVENTION
The invention is thus directed to a water-
metering installation protected against frost hazards,comprising a water meter connected to a water inlet
pipe and to a water outlet pipe, a base on which said
water meter is mounted, said water inlet and outlet
pipes being adapted to open into said base and to
extend within a trench dug in the ground, a casing
formed essentially of heat-insulating material which
surrounds the pipes and is open at the lower end thereof.
The invention is distinguished by the fact
that the top portion of said casing has a vertical
passage in which the base of the meter is engaged, said
base being attached directly to the insulating material
by means of cramps so as to prevent the formation of a
thermal bridge between the base and the exterior, the
water meter being located above the casing, and that the
meter is covered by a cap of insulating material, the
bottom edge of which is in contact with the top portion
of the insulating material of said casing.
The casing is essentially formed of heat-
insulating material which continuously surrounds the
pipes and the base and thus protects them against frost.
The bottom opening is located in a zone which
is not exposed to frost and is at a substantially
constant temperature, with the result that the casing
is maintained by heat exchange through said opening at
a substantially constant internal temperature at which
the pipes and the base are also maintained.
Moreover, attachment of the base by anchoring
directly in the heat-insulating material eliminates the
thermal bridges encountered in conventional
installations. While maintaining the same degree of
efficiency, this makes it possible to reduce the
thicknesses of heat-insulating material and thus to
reduce the external volume of the installation.
As a result of its small size, the
installation can accordingly be placed in position
without carrying out any special excavation and it is
thus possible to dig a simple trench comparable in
width to that required for laying pipes. This
consequently leads to the achievement of cost savings
in the realization of the construction project, both
in regard to the volume of soil displaced and in regard
to opexating times.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of an
installation in accordance with the invention.
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FIG. 2 is a sectional view taken along the
plane II-II of FIG. 1.
FIG. 3 is a longitudinal part-sectional view
to a larger scale showing the attachment of the water-
meter base to the heat-insulating material, this view
being taken along the plane III-III of FIG. 4.
FIG. 4 is a sectional view taken along the
plane IV-IV of FIG. 3.
FIG. 5 is a longitudinal part-sectional view
lG to a larger scale showing the housing which contains
the cap, this view being taken along the plane V-V of
FIG. 6.
FIG. 6 is a sectional view taken along the
plane VI-VI of FIG. 5.
FIG. 7 is a schematic longitudinal sectional
view of a buried installation in accordance with the
invention.
FIGS. 8 and 9 are schematic views similar to
FIG. 7.
DETAILED DESCRIPTION OF T~E INVENTION
In the embodiment of FIGS. 1 to 4, the
water-metering installation comprises a water meter 1
connected to a water inlet pipe 2 and to a water outlet
pipe 3 of polyethylene, for example. The water meter 1
is mounted on a base 4 into which said water inlet and
outlet pipes 2, 3 open.
Said pipes 2, 3 extend within a trench dug in
the ground and penetrate into the ground at the bottom 5
of the trench.
In accordance with the invention, the
installation includes a casing 6 of heat-insulating
material which forms the support stool of the
installation, surrounds the pipes 2, 3 and is open at
the lower end. The top portion 7 of said casing 6 has
a vertical passage 8 in which the base 4 of the meter is
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engaged. Said base 4 is attached directly to the
insulating material of the casing 6 by means which will
be described in detail below and are intended to prevent
the formation of a thermal bridge between the base 4 and
the exterior. The thickness of insulating material
which surrounds the base 4 is greater than the thickness
of insulating material which surrounds the pipes 2 and 3.
Moreover, the thickness of insulating material
which surrounds the means for fixing the base 4 in the
insulating material is at least equal to the thickness
of insulating material which surrounds the pipes 2 and 3.
The casing 6 of heat-insulating material
comprises a molded outer shell 9 of rigid plastic, the
internal face of which is lined with heat-insulating
material 10.
Said heat-insulating material 10 is preferably
expanded plastic such as a polyurethane foam.
Moreover, the meter 1 is covered by a cap 11
of heat-insulating material of the same type as the
casing 6. The bottom edge of said cap 11 is in contact
with the top portion of the heat-insulating material of
the casing 6.
The insulating cap 11 is in turn enclosed
within a plastic housing 12, the bottom edge 12a of
which is rigidly fixed to the top edge of the insulating
casing 6. Said housing 12 is provided with a lateral
door 12b.
In addition, the air space 13 which surrounds
the pipes 2, 3 communicates with the air space 14
located between the insulating cap 11 and the meter 1
via air ducts 15 formed in the top wall 7 of the
insulating casing 6.
It is also apparent from FIG. 1 that the
mating edges of the insulating cap 11 and of the
insulating casing 6 have complementary annular shoulders
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16b which fit one inside the other.
In the example illustrated, the meter 1 is
rotatably mounted on the base 4 so as to be capable of
displacement between a position of opening and closing
of the water supply. This arrangement is already known
and described in French patent No. 87 03453. In
consequence, the connection between the insulating cap
11 and the top portion of the insulating casing 6 is
adapted to permit rotational displacement of the meter 1
between the two above-mentioned positions as well as to
permit disassembly and replacement of the meter 1.
As can be seen in FIG. 3, the attachment
between the base 4 and the passage 8 formed in the top
portion 7 of the insulating casing 6 is achieved by
means of metal cramps 16a anchored in the insulating
material 10 of said casing. The ends of said cramps 16a
are located at a sufficient distance from the outer face
of the casing 6 to prevent any formation of thermal
bridges between the base 4 and the exterior.
The base 4 is made of molded metallic material
such as brass, for example. The base is provided with
a central annular tube which cooperates with a heat pipe
18 in order to carry out heat transfer. Said tube is
rigidly fixed to two vertical partition-walls which are
oriented along a diameter and ensure mechanical strength
- -and rigidity of the base.
At right angles to said diameter, provision is
made for two diametrically opposite cylindrical sleeves
which permit tight engagement of the pipes 2 and 3.
It can also be seen in FIG. 1 that the bottom
portion 9a of the rigid outer shell 9 is flared-out at
the lower end in order to achieve enhanced anchoring of
the casing 6 in the ground.
Moreover, the bottom edge of said flared-out
portion 9a has two diametrically opposite openings 17a,
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17b through which the water inlet and outlet pipes 2, 3
are intended to pass.
In the embodiment shown, the insulating casing
6 also surrounds a heat pipe 18 which extends vertically
between the base 4 and the floor 5 of the trench which
has been dug in the ground. Said heat pipe 18 penetrates
into the ground to a predetermined depth in order to
extract heat therefrom and thus to maintain the base 4
and the meter at a temperature which minimizes the risks
of frost.
In FIGS. 5 and 6, it is apparent that the cap
11 is so shaped as to be capable of pivoting about a pin
12c, which also permits opening and pivotal displacement
of the door 12b.
The door 12b opens and pivots about the pin
12c through an angle of 180.
Means for retaining the cap 11 in the top
position comprise a resilient metallic strip 12d.
When the cap 11 is disengaged by lifting it
above the shouldered portions 16b, it can be raised to
a higher position in which it will be retained by the
resilient strip 12d.
When it is desired to lower the cap 11,
pressure is exerted on the strip 12d so as to permit
sliding and downward displacement of the cap 11 along
the pin 12c.
The mode of operation is as follows :
- the operator opens the door 12b after having unlocked
it, and swings it back through an angle of 180 about
the pin 12c ;
- the operator lifts the cap 11 until it is held in the
top position by the strip 12d ;
- the operator causes the cap to pivot through 180~
about the pin 12c and carries out a servicing operation
on the meter ;
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- the operator performs the reverse operations in the
reverse order so as to re-close and lock the door.
The door 12b is fitted with a member 12e which
is adapted to cooperate with the cap 11 in order to
ensure that said cap is positioned and engaged on the
shouldered portions 16b when the door is closed again.
The member 12e is formed by a horizontal rib
located just above the top face of the insulating cap 11
when the cap is engaged and the door is closed again.
If the cap 11 is not correctly engaged, the
rib 12e is applied against the upper portion of the cap
11 and prevents the door 12b from closing.
In the embodiment of FIGS. 7 to 9, the
installation is completely contained within a well 19
which is formed in the ground and is of variable depth.
~ he well 19 is closed at the top by a
cover-plate 20 which serves to gain access to the meter
1. The upper portion of the well is provided with a
top extension 21 in the form of a sleeve, the top edge
21a of which is adapted to receive the cover-plate 20.
The internal surface of the top extension 21
is adapted to the external surface of the casing 6
which forms a support stool in order to permit relative
sliding motion between said top extension 21 and the
casing 6. It is thus possible, as shown in FIGS. 7, 8
and 9, to position the installation at variable depths
without having to modify the length of the casing 6.
It is only necessary for this purpose to ensure that the
axial length of the top extension corresponds at least
to the difference between the maximum and minimum depths
of the well 19.
The technical effects and advantages of the
installation in accordance with the invention are as
follows :
The continuous insulating material of the
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casing 6 delimits with the engaged insulating cap 11 a
substantially isothermal volume of air without any
thermal bridge, which protects the entire internal
hydraulic circuit of the installation against frost.
The opening at the bottom of the casing 6
which forms a support stool in fact permits heat
exchange with the ground by convection of air within
the internal space of the support stool and with the
internal space of the cap via the air duct 15 provided
for this purpose. The temperature of said internal
space therefore becomes substantially equal to the
temperature prevailing at the depth of burial in the
ground, this temperature being constant and usually
within the range of 4C to 12C. The heat pipe 18
connected to the base 4 enhances this effect of
protection against frost'by producing a heat transfer
which starts from a greater depth and therefore a
higher temperature.
It has thus been made possible to protect the
entire hydraulic circuit against frost as well as to
reduce wear of the water meter which, in the embodiment
in accordance with the invention, is protected against
thermal shocks. The reliability of the installation is
accordingly enhanced.
The flared-out shape of the casing 6 at the
lower end ensures stability of the installation in the ,
ground by providing a good seating for the support stool
as well as better pull-out resistance.
By virtue of its small external volume, the
installation is very easy to place in position and the
scope of work on the construction site is comparable to
the laying of simple pipes. Moreover, the smaller
quantity of materials employed in this reduced volume
results in low construction costs.
Positioning of the installation in the ground
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thus involves the following steps :
- a trench is dug from the main to the consumer and has
the necessary width for pipe-laying ;
- a hole of adequate size is bored so as to house a heat
pipe 18 at the location chosen for the installation ;
- a bed of sand is deposited at the bottom of the trench;
- the installation is placed vertically within the trench
while positioning the heat pipe 18 within the housing
formed by its borehole ;
- the inlet pipe is connected to the water supply main
and the outlet pipe is connected to the consumer's
piping system ;
- after connection, the water circulation is established,
whereupon the operation of the device and leak-
tightness are tested ;- the trench is closed by re-filling to the desired
level while maintaining the installation in the
desired position.
The technical effects mentioned above reveal
the advantages of the invention over existing devices.
Thus the installation ensures better protection against
frost, is more economical to construct, easier to install
as well as to transport since it is of smaller bulk and
therefore of lighter weight.
As will be readily understood, the invention
is not limited to the embodiments described in the
foregoing and alternative forms of construction may
accordingly be contemplated.
It is possible in particular to place a fine-
mesh grid at the bottom of the trench in order to ensure
cleanliness of the space 13 within the casing and to
prevent entry of insects or small animals. This grid
is preferably rigidly fixed to the installation and
mounted in the factory.
