FLOAT CHAMBER

CHAMBRE DE FLOTTEUR

English Abstract

A Jumper valve for use in the float chamber of a boiling water unit.
The valve consists of a body of circular horizontal cross section having a
vertical outer wall. The inner portion of the valve body includes a
central circular cut-out seat portion to accommodate a cylindrical seal,
the wall of the valve seat between the cut-out portion and the outer wall
being sloped in the manner of the surface of the frustrum of a cone.

Claims

The embodiments of the invention in which an exclusive property or privilege
is
claimed are defined as follows:
1. A boiling water unit comprising:
a nozzle adapted to permit ingress of water to the unit float chamber;
a temperature sensor:
a float:
a pivot arm tined at one end to the upper portion of the float and adapted to
pivot
about its opposite end: and
a valve seat affixed to the pivot arm, the valve seat having a central
hollowed
portion at least partially surrounded by a ramp surface, and a sealing member
shaped for
accommodation thereof in said hollowed valve seat portion, the arrangement
being such
that water entering said float chamber through said nozzle first contacts said
sealing
member along said ramp surface to contact and activate said temperature sensor
to control
a condition of the water in said float chamber for moving said float to
control the position
of said sealing member relative to said nozzle.
2. A boiling water unit as defined in claim 1 wherein said sealing member has
a substantially flat surface adapted for sealing contact with said nozzle.
3. The boiling water unit of claim 1 wherein said sealing member is of
such dimensions as to loosely fit within said hollowed valve seat portion at
normal
operating temperatures of the unit, but is adapted to expand under pressure
occasioned by
contact of said nozzle, forcing said sealing member against said valve seat,
to at least
substantially close said hollowed valve seat portion when said float rises in
said float
chamber causing said pivot arm to elevate said valve seat and sealing member
to close
said nozzle.
4. A boiling water unit as defined in claim 3 wherein the sealing member
is cylindrical and is of thickness greater than the width of the gap between
said nozzle and
said sealing member when said float rests on the chamber bottom.
5. The boiling water unit of claim 2 wherein said sealing member is of
rubber or a rubber substitute material.
6. A boiling water unit as defined in claim 1 wherein said ramp surface is
frusto-conical and completely surrounds said hollowed valve portion.

Description

CA 02040249 2000-03-29
Float Chamber
This invention relates to float chambers and is more particularly
concerned with float chambers useful in boiling water units such as
depicted and described in the specification of Australian Patent 531449.
In such a conventional boiling water unit, a float chamber is located
beside the upper portion of the boiling water tank, the arrangement being
such that the water level in the float chamber is identical with that in
the boiling water tank. When boiling water is drawn off from the tank, the
water level in both the float chamber and the boiling water tank is lowered
and a float, arranged to float on the water in the float chamber, falls
with the falling water level in the float chamber. A float arm connected
to the float opens a valve when the float has fallen to a predetermined
level, the valve when opened allows cold water under mains pressure to
enter the float chamber.
One problem associated with cistern fed type boiling water units
resides in the capacity to activate the thermostat sensor to switch on the
heating element in the boiling water tank as soon as possible after water
has been drawn from the boiling water tank.
In conventional such boiling water units, a jumper valve has been
provided to alternatively shut off and allow flow of water from the mains
supply to the float chamber. Above the maximum water level in the float
chamber conventional boiling water units incorporate a gauze sleeve housing
a sensor. This sensor is provided for the detection of water temperature
in the float chamber and is adapted to activate the heating element in the
main tank when a drop in water temperature in the float chamber is detected.
Conventional boiling water units have been provided with a tongue on
the float arm for the diversion of some of the water entering the float
chamber from the mains to the aforesaid gauze sleeve, whereupon the sensor,
once sensing the temperature of the water entering the float chamber from
the mains, will activate the aforesaid heating element. This arrangement
has proven satisfactory, but nevertheless is an arrangement which, for
optimum operation of the unit, might be improved upon. A further problem
which has arisen with conventional boiling water units resides in the fact
that the jumper valve adapted to close off the mains water supply has
incorporated a seal of rubber or a rubber substitute adhered to the valve
seat. This seal has tended, with closing pressure, to buckle, thus
providing a less than perfect seal with the mains water
_2_
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inlet. Clearly, this is undesirable and a further feature which can be
improved upon.
It is an object of this invention to ameliorate the above stated
disadvantages of conventional boiling water units.
This invention in one broad form provides a jumper valve
incorporating a central valve seat, a seal located in but not affixed to
said seat and a ramp surface at least partially surrounding said seat.
By way of example only one embodiment of apparatus in accordance with
this invention will now be described with reference to the accompanying
drawings wherein -
FIG. 1 is a section of a float chamber o~P a boiling water unit;
FIG. 2 depicts the jumper valve indicated at B in FIG. 1 in its open
position;
FIG. 3 depicts the .jumper valve of FIG. 1 in its closed position.
In the drawings, float chamber 1 contains water 2 at a level which
indicates that boiling water has been extracted from the main tank (not
shown>. Float 3 and float arm 4 operate by virtue of pivot 5. Jumper
valve shown generally at 15 is open as depicted in FIG. 2 so that water 10
is permitted to enter float chamber 1 through nozzle 11. Jumper valve 15
is provided with ramp surface 14 and side wall 12. Water 10 entering float
chamber 1 under pressure first strikes jumper valve sealing member 13 and
is then dissipated into float chamber 1, some of water 10 being included in
spray 8 which strikes gauze sleeve 6 which houses sensor 7. Some of the
water incorporated in spray 8 will strike sensor 7 which will operate the
heating element for 'the main tank.
As water continues to enter float chamber 1, float 3 will rise as the
surface level of water 2 rises. In due course, jumper valve 15 will assume
the position indicated in FTG. 3 relative to pipe 11, closing off ingress
of water to float chamber 1. Clearly, under the pressure of water 10,
seal 13 will expand and for this reason an expansion gap is left between
seal 13 and valve seat 16 as depicted in FIG. 2. Under expansion of
sealing member 13, this expansion gap will be fully occupied by the
expanded sealing member 13 which will nest against valve seat 16. When 'the
water level in float chamber 1 is again lowered, and water against enters
float chamber i from pipe 11, jumper valve 15 will again assume its
location relative to pipe 11 as indicated in FIG. 2 and seat 13 will
contract as
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shos~n in FIG. 2. The preferred thickness of sealing 13 is in the order of
2 millimetres and the preferred opening gap 17 is approximately 1
millimetre.

Representative Drawing