Note: Descriptions are shown in the official language in which they were submitted.
CA 02788853 2012-09-06
Canada
HEATING AND DISPENSING APPARATUS
Field of Invention
This Application relates to apparatus for heating and dispensing meltable
materials
generally, and in particular in respect of heating and dispending depilatory
wax.
Background of the Invention
In a conventional method, depilatory wax is heated in a container. The
attendant uses
a spatula, which may have a form similar to a wooden tongue-depressor, to
dispense the
depilatory wax. Each time wax is taken from the reservoir a new spatula is to
be used to
prevent the spread of disease. There are many problems that arise from this
approach. First,
maintenance of proper hygiene depends strongly on the diligence of the
attendant. Second,
even if diligent, the process may tend to result in the creation of a good
deal of waste. The
subject is addressed in US Patent 7,315,691 of Palkie, for example.
Summary of Invention
The following summary may introduce the reader to the more detailed discussion
to
follow. The summary is not intended to, and does not, limit or define the
claims.
In an aspect of the invention there is a depilatory wax dispenser assembly. It
has a
first accommodation, a second accommodation, and a heater. The first
accommodation
defines a chamber in which to contain molten wax. The first chamber having a
discharge
through which molten wax may flow upon demand. The second accommodation
defines a
seat in which to heat a reserve supply of molten wax for replenishing the
chamber. The
heater is mounted to the second accommodation. The dispenser has a heat flow
path from
the heater to the second accommodation, and therefrom to the first
accommodation.
In a feature of that aspect of the invention the second accommodation is
linked to the
first accommodation by a thermal conduction bridge. In another feature, the
assembly
includes a third accommodation defining a second seat in which to heat a
second reserve
supply of wax for replenishing the chamber. In a further feature, the assembly
includes a
second heater mounted to the second seat, and the second heater also
indirectly heats the first
accommodation. In another feature, the first and second seats are mounted
symmetrically to
the first accommodation. In still another feature, the first accommodation has
a body
defining a surrounding wall of the chamber. The second accommodation is
mounted adjacent
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to the first accommodation. The body has a lower region and an upper region;
and the
thermal conduction bridge is mounted to the upper region of the body.
In still another feature, the discharge includes an infeed, and the infeed
draws from
the chamber in the lower region of the body. In a yet further feature, the
assembly includes
an outflow catchment accommodation, and the outflow catchment accommodation is
also
heated. In a further feature, the outflow catchment accommodation defines a
seat for a liner
in which to hold molten wax received from the discharge of the body. In
another further
feature, the outflow catchment accommodation is heated indirectly by thermal
conduction.
In still another feature, a heat flow path is defined from the heater of the
second
accommodation to the first accommodation, and from the first accommodation to
the outflow
catchment accommodation. In yet still another feature, the discharge has an
outlet mounted
above the outflow catchment accommodation such that, in use a vertical
projection of the
discharge projects onto the outflow catchment accommodation.
In another feature, the assembly includes a lid for the first accommodation,
the lid is
movable between open and closed positions, and, when in the closed position,
the lid
obstructs entry of contaminants into the first accommodation. In a further
feature, the
discharge of the chamber is mounted to the lid, such that when the lid is
removed, the
discharge is also removed, whereby cleaning of the discharge is facilitated.
In another
feature, the assembly includes a pressure source operable to raise pressure
inside the first
accommodation above external ambient. In still another feature, the pressure
source is an air
pressure source mounted to pressurize an air space in an upper region of the
chamber,
thereby also pressurizing wax therein.
In another aspect of the invention there is a depilatory wax dispenser in
which the
outlet of the discharge stands proud of all adjacent structure and thereby
facilitates cleaning
thereof. In still another aspect of the invention there is a depilatory was
dispenser apparatus
that has a discharge and a receptacle support structure in which to hold a
disposable
receptacle, and in which the receptacle support structure stands proud of all
adjacent
structure, thereby facilitating cleaning thereof. In another aspect, the
receptacle support
structure is positioned beneath the outlet of the discharge assembly. In
another aspect the
receptacle support structure is heated. In a feature of that aspect the
receptacle support
structure (and thereby the receptacle itself) is heated by conduction of heat
from a heat
source remote from the receptacle support structure.
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In another aspect of the invention there is a depilatory wax dispenser. It has
a
reservoir for accommodating a charge of flowable wax; a heater operable to
heat the
reservoir; and a discharge by which the wax may exit the reservoir. The
discharge has an
inlet and an outlet. There is a temperature sensor mounted adjacent to the
discharge inlet.
In a further aspect of the invention there is a depilatory wax dispenser. It
has a
reservoir for accommodating a charge of flowable wax; a heater operable to
heat the
reservoir; and a discharge through which wax may exit the reservoir. There is
a pressure
source, the pressure source being operable to establish a positive pressure in
the reservoir
relative to external ambient pressure.
In a feature of that aspect of the invention, the source of pressure is an air
pump. In
another feature, the air pump is operatively connected to pressurize air in
the reservoir above
wax therein. In still another feature the discharge has an inlet located
proximate to a
lowermost location in the reservoir. In yet another feature the discharge has
an inlet and an
outlet, and the outlet is mounted at a higher elevation than the inlet.
In another aspect of the invention, there is a depilatory wax dispenser. It
has a
reservoir for accommodating a charge of wax; a heater operable to heat the
reservoir; and a
discharge through which wax may exit the reservoir. The discharge has an inlet
and an
outlet. The inlet of the discharge is located at a higher elevation than the
outlet.
In a feature of that aspect of the invention, the discharge includes a feed
conduit, the
feed conduit including the inlet; and the feed conduit is mounted
eccentrically in the
reservoir. In another feature, the reservoir has an upstanding sidewall and
has an hydraulic
diameter; and the feed conduit is mounted in the reservoir less than 1/4 of
the hydraulic
diameter from the sidewall.
In yet another aspect of the invention there is a depilatory wax dispenser. It
has a
reservoir for accommodating a charge of wax; a heater operable to heat the
reservoir; and a
discharge through which wax may exit the reservoir. The discharge has an inlet
and an
outlet. The inlet is located within the reservoir and is located lower than
the outlet. The
heater is mounted to heat an upper region of the reservoir distant from the
discharge inlet.
In a feature of that aspect of the invention, the assembly includes a pressure
source,
the pressure source being operable to maintain a pressure within the reservoir
greater than
ambient pressure. In another feature, the pressure source is an air pump. In a
further feature,
the air pump is operatively connected to pressurize an airspace above wax
contained in the
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reservoir. In another feature, the reservoir has a body defining a chamber in
which to hold
molten wax; and the reservoir has a lid mountable to the body in sealing
relationship. In still
another feature, the discharge is mounted to the lid, whereby when the lid is
removed the
discharge is also removed.
In another aspect of the invention there is a depilatory wax dispenser. It has
a
reservoir for accommodating a charge of wax; a heater operable to heat the
reservoir; and a
discharge through which wax may exit the reservoir. The discharge has an inlet
and an
outlet. The inlet is located within the reservoir and is located lower than
the outlet. The
reservoir has a body defining therewithin a chamber in which to contain molten
wax. The
reservoir has a lid mountable to the body. The discharge is mounted to the lid
whereby when
the lid is removed from the body the discharge is also removed.
In a feature of that aspect, the discharge includes a feed conduit, the feed
conduit
includes the inlet, and, when the lid is mounted atop the body the inlet is
located distant from
the lid in a lower region of the reservoir. In another feature, the wax
dispenser includes a
pressure source operably mounted to maintain a positive pressure within the
reservoir.
In another aspect of the invention there is a method of operation. The method
of
operation may include one or more of the steps of: heating a main reservoir of
wax from a
remote heat source by thermal conduction from adjacent structure. The method
may include
keeping a re-supply of wax, such as an unopened canister (or canisters) of wax
heated and
ready while using was from the main reservoir. The method may include heating
both the
main reservoir and the re-supply from the same heat source. The method may
include
heating a receptacle or receptacle support structure of heated wax that has
been dispensed for
use. The method may include using a disposable receptacle and disposing of
that receptacle
after use thereof. It may include repeated use of a spatula, the spatula and
the disposable
receptacle being used for only one customer, and then disposed after use. The
method may
include controlling operation of the heater based on temperature sensed at the
inlet of the
discharge assembly. The method, in any combination of the foregoing steps may
include
keeping a lid on the main reservoir while in use, thereby discouraging
contamination of the
wax in the reservoir. The method, in any combination of the foregoing steps,
may include
maintaining the inside of the reservoir at a pressure higher than ambient. The
method in any
combination of steps may include urging wax through the discharge with air
pressure.
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Brief Description of the Illustrations
These and other features and aspects of the invention may be explained and
understood with the aid of the accompanying illustrations, in which:
Figure 1 is a perspective view of a dispensing apparatus according to an
aspect of the
present invention;
Figure 2a is a top view of the dispensing apparatus of Figure 1 with lid on;
Figure 2b is a top view of the dispensing apparatus of Figure 1 with lid off,
and one
of the side resupply canisters removed from its seat;
Figure 3a is a front view of the dispensing apparatus of Figure 1;
Figure 3b is a longitudinal section of the dispensing apparatus of Figure 1
taken on
section `3b ¨ 3b' of Figure 2a;
Figure 4a is a side view of the dispensing apparatus of Figure 1; and
Figure 4b is a side section through the main central chamber taken on section
`4b ¨
4b' of Figure 2a.
Detailed Description
The description that follows, and the embodiments described therein, are
provided by
way of illustration of an example, or examples, of particular embodiments
incorporating one
or more of the principles, aspects and features of the present invention.
These examples are
provided for the purposes of explanation, and not of limitation, of those
principles, aspects
and features of the invention. In the description, like parts are marked
throughout the
specification and the drawings with the same respective reference numerals.
The drawings
may be taken as being to scale, or generally proportionate, unless indicated
otherwise.
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The terminology used in this specification is thought to be consistent with
the
customary and ordinary meanings of those terms as they would be understood by
a person of
ordinary skill in the art in North America. The Applicants expressly exclude
all
interpretations that are inconsistent with this specification, and, in
particular, expressly
exclude any interpretation of the claims or the language used in this
specification such as
may be made in the USPTO, or in any other Patent Office, other than those
interpretations for
which express support can be demonstrated in this specification or in
objective evidence of
record, demonstrating how the terms are used and understood by persons of
ordinary skill in
the art, or by way of expert evidence of a person or persons of experience in
the art.
The term "molten" is used in several places herein in the context of waxes or
waxy
materials, and, in particular in the context of depilatory wax. It is intended
to indicate that
the heated material has reached a sufficiently softened state to be flowable,
without
necessarily being heated to such an extent that it is a runny liquid. That is,
it is no longer
firmly solid, but it is also not necessarily completely liquid. It will deform
and flatten out
under its own weight, like a paste or thick glue or resin. It may be
considered a soft
rheological solid or semi-solid. If placed in a bowl, it will eventually find
its own level,
although it may move slowly. For any given wax there is a desirable
temperature range in
which the wax is maintained in a softened condition, without becoming too
liquid, not unlike
maintaining butter at a temperature that is soft enough to spread with a
spatula or butter
knife, but not soft enough to have melted into a runny liquid. For depilatory
wax, that
suitable temperature range may be fairly narrow. The "molten" material may be
highly
viscous. In use for such wax the range of moderately elevated temperatures may
be in the
range that is higher than body temperature (and higher than the effective
melting
temperature, or softening point, of the wax), and less than 100 C at the
outlet. In particular,
the outlet temperature for such an application may typically be controlled in
the range of
about 65 ¨ 75 C. Internal temperatures may be somewhat higher. Depilatory wax
may be
both oily and quite sticky, and may easily spread to any surface that may be
inadvertently
touched. As such maintain the apparatus in a clean state may be quite
challenging.
Referring to the general arrangement of Figure 1, there is a dispenser, or
dispenser
assembly, indicated generally as 20. Dispenser assembly 20 may be a dispenser
for flowable
materials, such as highly viscous fluids or rheological solids, and, in
particular for materials
whose viscosity is strongly temperature sensitive, which may not flow (that
is, they may be
solidified or substantially solidified) at ambient (typically room)
temperature but that may be
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flowable at moderately elevated temperatures. In one embodiment assembly 20
may be used
for dispensing materials such as wax, and, in one particular use, depilatory
wax.
In the exemplary embodiment shown, dispenser assembly 20 may include a first
part
or portion or element or module, identified as a first accommodation 22, a
second part or
portion or element, or module, identified as a second accommodation 24, and a
third part or
portion or element or module identified as a third accommodation 26. The
dispenser
assembly may also include a heat source, or heating element, or heat exchanger
element,
which may be identified generally as 28.
First accommodation 22 may include a body 30 which includes or defines a
containment shell, or wall structure, that has a bottom, or bottom wall, 32
and an upstanding
peripherally extending containment wall or sidewall, 34. Items 32 and 34 co-
operate to
define a chamber 36 in which to contain molten fluid, such as wax, and, in
particular, such as
depilatory wax. The wall structure defining chamber 36 may also be termed the
main or
primary, or active, reservoir of assembly 20, and body 30 may be the central
structural
assembly or module of assembly 20 more generally. In the illustrative
embodiment shown,
body 30 may have the form of an upright standing circular cylinder that stands
upon a
platform, or pedestal, identified as a base 40. In the embodiment shown, body
30 and the
main structural components thereof may be made from a thermally conductive
material, such
as a metal. In one embodiment that metal may be mild aluminum. Body 30, or
substantial
portions thereof, may also be provided with a thermally insulative exterior
layer or covering,
in whole or in part. Whether an insulating layer, such as a plastic outer
wall, is used or not,
the exterior surface is substantially clear of obstructions, such as may
facilitate washing and
maintenance of the unit in an hygienic, clean condition.
Body 30 may include a closure member 42, illustrated as lid 44. Lid 44 seats
upon
upper rim 46 of sidewall 34, and has a circular seal 48 by which to ensure
sealing
engagement of lid 44 with rim 46. As may be seen body 30 includes an indexing
feature 50
for mating engagement with a corresponding indexing feature 52 of lid 44.
Feature 50 may
be a pin 54 mounted in rim 46, and feature 52 may be a corresponding socket,
such as a blind
hole 56, in lid 44. There are many possible alternatives. As may be noted, the
central
portion 58 of lid 44 stands proud of the outer peripheral land 60, and seal 48
seats at the
circumferentially extending shoulder 62 formed where flat horizontal land 60
meets central
portion 58. When closed, central portion 58 seats concentrically within
peripheral wall 34,
and land 60 seats in opposition to rim 46. As seated, indexing features 50, 52
matingly
engage, ensuring a unique angular orientation of lid 44 relative to body 30.
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Looking again at lid 44, there is a central bore, or aperture, 64, that has a
widened
lower entrance, or bell-mouth, or rebate, or alcove, or niche, or relief,
indicated as 66. A lid
securement, or lid securement assembly, is shown generally as 68. Lid
securement assembly
68 includes a tightening grip, or handle 70 having an internally thread blind
bore 72, and a
seal 74. Handle 70 is prevented from separating from lid 44 by a retainer,
which may have
the form of a housing 76. Handle 70, or the shaft upon which it is mounted,
may have an
aperture formed therethrough to permit the installation of a rod or bar, or
the shaft of a screw-
driver, for example, such that, in the event that the seal of the lid to the
body of the assembly
should become sticky the rod or bar may be passed through to provide the
operator with
enhanced leverage to removed lid 44.
Body 30 has a central rod or central mandrel 80. At its first, or lower, end
mandrel 80
has a reduced diameter stub or shank 82 which seats in, and extends through, a
mating
aperture 84 in bottom wall 32, and is secured in place with a locknut. Another
0-ring seal 86
is located at the shoulder of the stub to provide a seal about aperture 84. At
its second, or
upper, end mandrel 80 is again narrowed, in this instance to an end shank 88,
which is
externally threaded along its most distal portion. Mandrel 80 is hollow to the
extent that it
has a central bore defining an air flow conduit or passageway 90, that
passageway having an
inlet at the bottom end, as indicated at 92, and an outlet 94 at the top end
short of the
threaded shank.
Looking at the cross-sectional view of Figure 4b, a discharge, or outflow, or
discharge assembly, 100 is also mounted to lid 44. Discharge assembly 100
defines a flow
path, or passageway, or conduit, identified as 102, however named, by which
the contents of
chamber 36 may exit, leave, egress, or otherwise flow out of chamber 36 and
thereby be
dispensed, the direction of flow being indicated by the arrows on flow path
102. It has an
inlet 104 inside chamber 36; an outlet 106 outside chamber 36, and a control
or governor,
such as may be identified as a gate, spigot, valve, or tap 108 intermediate
inlet 104 and outlet
106 by which to regulate flow through passageway 102. Tap 108 is a flow
governor that is
movable between a closed (no flow) position or condition, and an open
position.
Discharge assembly 100 may include an infeed, such as may include an intake
pipe
110. Pipe 110 may have a first end mounted to lid 44, and a second, distal,
end distant from
lid 44. As shown, inlet 104 may be at the distal end of pipe 110, and, as
installed, may be
proximate to bottom 32 such that inlet 104 may remain submerged until the
reservoir, that is
CA 02788853 2012-09-06
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chamber 36, is substantially empty. That is, inlet 104 is located in a lower,
or substantially
lowermost region of chamber 36 (and of body 30) in use. In one embodiment,
pipe 110 may
be mounted eccentrically relative to the center of chamber 36. That is,
assuming that
chamber 36 has a cross section, a centroid, and an hydraulic diameter Dh, or,
if circular, an
actual diameter, there is a radial distance from the center (or centroid) of
the chamber to the
surrounding peripheral containment wall. Taking the radius as being half the
diameter (or
hydraulic diameter, as may be), the centerline of pipe 110 is then radially
closer to peripheral
containment wall 34 than to the centroid (that is, in a right cylinder, the
central axis of
revolution). In one embodiment the centerline of pipe 110 is between 10% and
30% of the
length of the radius from the outer wall. In one embodiment is is about 1/5 to
1/4 of the
radius from the wall. In one embodiment pipe 110 may have an internal diameter
of 8 mm to
10 mm, and the spigot and discharge passage may have an internal diameter of
12 mm.
When lid 44 is removed, discharge assembly 100 is also removed, and, given the
relative simplicity of construction, discharge assembly 100 can then be
cleaned relatively
easily even without emptying chamber 36 or tipping body 30. At the same time,
too, it may
be noted that when lid 44 is removed, chamber 36 may also be easily cleaned,
given that it
has the form of a smooth-walled bucket, or cylinder with a central mandrel. A
temperature
sensor 114 may be mounted to bottom wall 34 underneath inlet 104, in effect
measuring the
inlet temperature of the molten material. An over-temperature sensor and limit
switch 116 is
also mounted at or near this location. For the application of maintaining
depilatory wax
suitably warm, the over-temperature switch may be set at 75 C, such that if
normal
temperature control should fail, the machine will automatically shut off
During normal
operation the inlet temperature for depilatory wax may typically be in the
range of 68 ¨ 70 C.
When lid 44 is positioned in place in it closed position, as shown in Figures
3b and
4b, the male external thread of upper end shank 88 of mandrel 80 are engaged
by the female
internal threads of handle 70, and, as tightened, axial tension develops in
mandrel 80
sufficient to compress 0-ring seals 74 and 86 as peripheral land 60 engages
upper rim 46.
When so engaged, chamber 36 is sealed, and may be pressurized, as explained
below. To the
extent that fluid, or quasi-fluid matter, such as molten depilatory wax, has a
higher pressure
P1494 at inlet 104 than external ambient Punt) at outlet 106, that fluid may
tend to flow
outwardly through passageway 102. On turning spigot handle 112 appropriately,
the flow
governor 108 is then movable between the closed (no flow) position or
condition, and an
open position whether partially or fully open as may be suitable, in which
flow is permitted
through the discharge. Lid 44 may be provided with a pressure relief valve
(not shown).
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One may note that even without removing lid 44 the outlet portions of
discharge assembly
100, namely outlet 106, tap 108 and spigot handle 112, are mounted in an
exposed location.
They jut out from, i.e., stand forward of, or proud of, and clear of, all
other adjacent structure
such that they are well exposed to facilitate cleaning. That is, the pouring
or dispensing
outlet is not mounted within a housing or shell, but is mounted, and extends,
externally of the
shell of the unit.
Dispenser assembly 20 also includes third accommodation 26, which defines a
receptacle or receptacle support structure 120 which defines a seat 122 in
which a receptacle
124 such as a disposable paper cup 126 may be placed. Seat 122 may have a
conically
tapered sidewall. The shape of the receptacle, cup 126, as indicated matches
the size and
shape of seat 122 such that a substantial portion of the surface area is in
contact with the seat.
In the embodiment illustrated, paper cup 126 may typically be of the size of a
paper coffee
cup, such as may hold, in one example, perhaps 50 ml ¨ 150 ml of dispensed
material at a
time. Support structure 120 may be made of thermally conductive material.
While copper or
other high thermal conductivity metals may be used, the inventors have found
that aluminum
provides good thermal conductivity. The metal provides a thermally conductive
path
between body 30 and receptacle 124. It may be noted that seat 122 has a large
sidewall
surface area extending downward to the bottom of the support structure such
that a cup 126
resting therein may tend to be heated over the full depth of the fluid
collected in the cup. A
second handle 128 is mounted to the front of support structure 120 to permit
an operator to
steady assembly 20 with one hand while turning spigot handle 112 to open or
close the valve.
As may be seen in Figure 2a, given the relationship of indexing features 50
and 52, lid 42 can
seat in only one position relative to support structure 120. As such, a
vertical projection of
outlet 106 projects onto the footprint of receptacle support structure 120,
meaning that
gravity will direct the outflow of discharge assembly 100 into a receptacle
124 mounted in
support structure 120. The central bottom of support structure 120 is open, so
that if no
receptacle 124 is mounted therein, wax (or other fluid) will not collect on
the structure.
The flow from discharge assembly 100 to receptacle 124 is one way. Wax (or
such
other material as may be dispensed) cannot flow back uphill into chamber 36,
and once
dispensed has no further contact with chamber 36 or with the remainder of the
contents of the
reservoir of material yet to be dispensed. Given that the lid is sealed, and
the only outlet is
the spout, the chance of contamination of the reservoir, and the opportunities
to contaminate
the reservoir, may tend to be reduced. Further, there is clear vertical
separation between
outlet 106. Support structure 120 extends forwardly clear of the rest of the
structure of
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assembly 20, such that it is easily accessible for cleaning. It is not
obstructed on left or right.
The clearance from discharge 100 gives clear access from above. There is no
obstruction
from below. Support structure 120 stands out on a cantilever such that it
projects away from,
that is, it stands forwardly proud of, not only body 30, but also of all other
nearby structure
and is thereby exposed to facilitate access during operation and to facilitate
cleaning
afterward. The remainder of the structure is sealed, and has smooth external
surfaces which
may also facilitate cleaning. That is, the seat and the disposable receptacle
are not mounted
within a housing or shell, but are mounted, and extend, externally of the
shell of the unit.
The root of support structure 120 is shaped to conform to the external shape
of body 30, and
support structure 120 is mounted to body 30 in thermally conductive
relationship therewith.
In the embodiment shown, attachment is by threaded fasteners, although the
parts could be
welded together, or made as a single cast aluminum (or other suitable metal)
monolith.
The second part or, or module, identified as a second accommodation 24 is
mounted
to the first part or module. In the embodiment there is a left hand module
130, and a right
hand module 132. Each being mounted, or hung from and to one side of, body 30
of the
main, active, or primary, reservoir. Second accommodation 24 may have the form
of either
of modules 130 and 132, or both together. Although two such modules are shown,
there
need not be more than one, and there could be more than two. In the embodiment
shown two
such modules are convenient inasmuch as the main reservoir of chamber 36 may
have a
volumetric capacity slightly larger than two standard containers of wax, such
that two
containers of wax would be considered a full re-fill of chamber 36. That is,
chamber 36 may
have a volume of somewhat over 2 L, where each replacement canister has a
volume of 1 L
and a mass of about 800 g. of wax. A typical salon may use 1 L ¨ 2 L of wax in
a day. In the
embodiment shown, there is left and right hand symmetry about the central
vertical plane x-z
plane. Inasmuch as modules 130 and 132 are the same, other than to the extent
that they are
left and right handed, and therefore a description of one may be understood
also to be a
description of the other. Considering left hand module 130 as being
representative, module
130 has a body 134 that includes a base 136, and upstanding, peripherally
extending sidewall
138 and a closure member, or retainer 140. In the embodiment shown, body 134
may have
the form of a right circular cylinder, and defines therewithin a containment
vessel or seat.
Unopened re-supply containers of material are indicated as 142. As noted
container 142 may
contain a phase changing material, such as wax, that is transformed from a
solid or
substantially solid, non-readily-flowing state at one temperature, to a
liquid, or substantially
liquid, flowable state at a warmer temperature.
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Base 136 may include a highly thermally conductive inner layer 137 and an
outer
layer 139. Outer layer 139 need not be thermally conductive, and may be
thermally
insulative. Sidewall 138 may include, or may have mounted to it, a source of
heat such as
heater 28. While it would be possible to have an external source of heat, such
as hot glycol
heated elsewhere, and a heat exchanger, in the embodiment illustrated the heat
source may be
an electric heating element mounted within body 134. In the embodiment
illustrated, base
136 may be made of a thermally conductive material such as solid aluminum, or
may be
made of a thermally insulative material. Sidewall 138 may include an inner
wall 144, and
outer wall 146. The relative thicknesses of walls 144 and 146 may not be to
scale. A heating
element, which may be a rubberized flexible heating array, or heating element,
150 having
electric heating members, may be wrapped externally about inner wall 144, such
that inner
wall 144 may be heated thereby. Either or both of inner wall 144 and outer
wall 146 may be
made of a thermally conductive material, again, such as aluminum. Outer wall
146 may be
made of a less thermally conductive material, and may be made of a thermal
insulator.
Alternatively, a layer of thermal insulation may be wrapped about heating
element 150
within outer wall 146. Inner wall 144 may have a radially outwardly extending
flange, or
may be surmounted by a cap ring, either being indicated as 154. As shown, the
assembly is
welded at top and bottom to prevent leakage. The top of the wall is overlain
be an annular
cap ring 156 which is easily cleaned. Finally, there is a retainer 158 which
is removed to
permit the introduction of re-supply container 142. Retainer 158 has a
radially inwardly
extending wall or flange that captures container 142 in seat 148. A see-
through plastic cap or
dome (not shown) may cover the central aperture in retainer 158. As with the
exterior wall
of main reservoir body 30, the exterior of wall 146 is smooth and
substantially clear of
obstructions to facilitate cleaning.
Each of modules 130 and 132 is mounted to the main body 30 by a structural
member
(or members) defining a thermally conductive bridge 160. Thermal bridge 160
may be made
of a thermally conductive material. An example of such a material is aluminum,
including
mild 1100 aluminum. A first end of thermal bridge 160 is in thermally
conductive
attachment to body 134, and, in particular, to thermally conductive inner wall
144, which is
itself in thermally conductive close contact with heating element 150. A
second end of
thermal bridge 160 is mounted in thermally conductive attachment to body 30 of
the main,
active, reservoir. In the embodiment shown, module 130 (or 132) is secured to
main body 30
by threaded fasteners as indicated at 162. The various modules could be welded
together, or
made as a casting.
CA 02788853 2012-09-06
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By this means a thermally conductive heating path is established from heating
element 150 through module 130 (or 132 as may be), into the main reservoir of
body 30, and
thereby into the material to be maintained in a molten state that is contained
within body 30.
The thermally conductive path also extends to discharge assembly 100. That is,
one problem
with highly viscous depilatory wax is that it may tend to solidify in an
outlet tap. However,
as shown the outlet tap is made of thermally conductive material, such as
aluminum, and is
thereby maintained at a sufficiently high temperature to maintain the wax in a
flowable
condition, even when the tap is closed. Even if the machine is turned off, and
the wax
solidifies in the outlet passageway, once the machine is turned on again, the
heat in the
discharge assembly will, after some time, heat and re-melt the wax in the
passageway. If that
is unsatisfactory, lid 44 can be removed, permitting the entire discharge
assembly to be
washed in hot water, such as water having a temperature in excess of 75 C.
In addition to providing a footing for assembly 20 more generally, base 40 may
define a housing or shell, or enclosed space in which to mount control devices
and circuitry.
For example, there may be, mounted within base 40 an air pump 170; an air
pressure switch
172; a controller 174; and a transformer 176 connected to receive external
line power,
whether at 60 Hz 120 VAC, or at 50 Hz 220 VAC.
Air pump 170 draws air from external ambient (base 40 not being sealed), and
feeds it
into the dome in lid 44 through the passageway in mandrel 80. Since chamber 36
cannot be
filled higher than the dome in lid 44, the air pressure P36 established there
will be established
above the molten wax, W, whatever the level of wax may be in chamber 36.
Appropriate
flow can be obtained with even modest pressure levels. Air pump 170 may
operate at 1/2 psig
¨ 1 psig in normal operation. In one embodiment is has a maximum pressure of
4.5 psig.
Overpressure switch 172 is operable to shut off air pump 170 in the event of a
failure of the
pressure control of pump 170. Over-pressure switch 174 may be set, for
example, at 5 psig.
As noted above, lid 44 may also have a pressure relief valve as a further back-
up to over-
pressure switch 172. It is known to pump wax and oils with pumps. However, in
the
embodiment illustrated, the working fluid, being wax, does not pass through
the pump.
Rather, the pump is upstream of the wax, and only pumps air. Thus the wax
cannot make a
sticky, hard-to-clean, mess inside the pump. Moreover, the use of the air pump
applies an
even, gentle pressure to the entire top surface of the wax, and, given that
the flow is slow and
the sidewalls are heated, over a period of hours the wax recedes in chamber 36
evenly under
gravity, such that the walls are substantially self-cleaning in use.
CA 02788853 2012-09-06
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Controller 174 operates to control air pump 170, and also to cycle operation
of the
heating elements in response to the temperature sensed at temperature sensor
114. It also
controls operation of air pump 170. Controller 174 is mounted such that its
display and
control key-pad module 178 is externally accessible, most typically at the
front of base 40.
An operator may choose the desired molten wax temperature. The apparatus will
then heat the wax until the temperature is achieved, at which time the
keyboard display will
indicate that the target temperature has been achieved. The controller is an
"on-off'
controller that has a hysteresis loop, which, typically, is a 2 degree range,
from 1 C below
target temperature to 1 C above target temperature. Alternatively, or
additionally, the
controller may use a timer to establish a minimum "off' time, to prevent the
controller from
cycling the heating elements too rapidly. Either approach will yield a saw-
tooth time v
temperature characteristic. In apparatus 20, the function of maintaining
suitable temperature
in the main reservoir, or active supply, is combined with the function of pre-
heating the next
batch of wax, using a single heating system. When initially activated, heating
elements 150
may each operate at a maximum power of 175 W, or 350 in total. The heaters may
have
three different manual settings for 175 W, 150 W and 125 W each. When
operating
temperature is reached, the controller may reduce the power to 125 W, and may
run that
power on a partial duty cycle, which may be roughly 20 ¨ 25 % of the time
"on", and 75 ¨
80% of the time "off". At steady state, a typical duty cycle may be 3 ¨ 4
minutes "on" and
15 minutes "off", such that the machine may operate at an average steady state
power
equivalent to about 50 ¨ 60 W. This is equivalent to the heat of a relatively
dim conventional
incandescent bulb. Although controller 174 may be a digital processor control,
the control
functions are sufficiently simple that an analog circuit could also be used,
with temperature
selection being by thermostat rather than a digital keypad, and a multi-
position switch being
used for power range selection.
It may be noted that heating of the main reservoir is indirect. There is no
electrical or
other heating element mounted to the main reservoir body 30 itself. The
reservoir is heated
externally, by an external source of heat, through thermal conduction from
adjacent
intermediate structure, in this case the pre-heat modules 130 and 132.
Further, a single heat
source (or sources) at the re-fill reservoir seat heat not only the re-fill
containers in module
130 (or 132), but also the main reservoir i.e., body 130; the output
receptacle support
structure 120; and the discharge assembly 100. The indirect heating of the
main reservoir,
externally by thermal conduction, will occur whether there are canisters of re-
supply wax in
the re-supple pre-heat seats of modules 130, 132 or not. In the embodiment,
primary heating
CA 02788853 2012-09-06
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is of the re-supply seat, with the main, active reservoir being more distant
from the heating
element than the re-supply pre-heat seat. In an alternate embodiment or
embodiments, each
of these heating functions could be separate, each module could have a
separate heater, and a
separate temperature control. However, a single heating circuit with elements
in each pre-
heat module, is relatively simple.
A common problem with depilatory wax is that it takes a long time for a
canister of
wax to melt. In this context, "a long time" may exceed half an hour, depending
on the size of
the heater. When the current main supply has been consumed, it may be
convenient to have
a pre-melted supply ready to hand. In some apparatus a canister of solid wax
is opened and
placed in a seat in an inverted, or predominantly inverted, orientation,
typically above some
kind of grill or collection apparatus. When the canister is heated, the wax
melts and drips
down into the collection apparatus, whence it is dispensed. In other apparatus
the wax may
be emptied upside down into the unit as a slug of solid wax. In the view of
the inventors this
may tend to lead to an apparatus that is one or both of (a) unnecessarily
complicated; and (b)
more difficult to clean.
As described, apparatus 20 includes a re-supply pre-heating function, namely
by the
placement of a still sealed (i.e., unopened) canister of re-supply wax in
heated seat 148.
When the supply of wax in the active main reservoir chamber 36 is running low,
the pre-
heated canister is opened and poured into chamber 36. The location of heating
element 150
about wall 144 ensures that the pre-heated wax is at least as hot as the wax
in chamber 36.
Since the canisters are unopened in the pre-heat modules, when they are
removed there is no
sticky residue to clean out of seat 148, and a further resupply canister may
be placed in seat
148 for the next re-fill.
The use of a pressurized tank permits simplification of the outflow, and, by
permitting the outflow to be simplified and mounted to lid 42, facilitates
ease of cleaning.
The only moving part is the valve. Infeed pipe 110 is within chamber 36, and
so is
maintained at the internal temperature of chamber 36. The inventors have
observed
empirically that the circulation of molten wax in chamber 36 appears to be
aided when body
30 is heated from the top, rather than from the bottom. As shown in the
Figures, thermal
bridge 160 is mounted to an upper region of body 30, rather than to a lower
region thereof
Expressed differently, thermal bridge 160 is mounted adjacent to the upper end
of body 130,
proximate rim 46, and distant from bottom wall 32. Bridge 160 may be located
at a height
that is within 1/4 of the overall height of chamber 36 from the top thereof. A
further empirical
observation by the inventors is that the circulation of molten wax in chamber
36 is such as to
CA 02788853 2012-09-06
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encourage placement of infeed 110 relatively close to the outer wall (as
described above). A
further observation is that location of the temperature sensor adjacent inlet
104 of discharge
assembly 100 may tend to provide satisfactory operation. When the unit is
heating, if the
wax in chamber 36 is in its solidified condition, the wax that melts most
quickly will tend to
be the wax most closely adjacent to sidewall 34 (which is a large, relatively
thick wall
aluminum heat conductor), and of that wax near the wall, the wax closest to
bridge 160 may
tend to melt most quickly. Placement of infeed 110 relatively close to the
outer wall (for
example, less than 1/3 or 1/4 of the radius of chamber 36 therefrom) means
that the discharge
assembly may come to working temperature faster, and be operable to discharge
wax sooner,
than if placed more centrally in the chamber. An initial amount of wax may be
discharged to
disposable cup 126 for use, and while it is being used the remainder of the
wax in chamber
36 may continue to melt.
The overall assembly may have the general appearance of a coffee urn with two
cylinders on either side that contain re-fill material. The exterior of the
unit is substantially
free of adornment or of external fittings or other obstructions that do not
facilitate easy
cleaning. Maintaining the predominantly smooth metal exterior in a clean
condition may
tend to promote both actual hygiene, and also the perception of hygiene by
customers.
In use, the attendant pours as much wax as may be needed into disposable cup
126.
The attendant may then use one spatula to spread that wax, rather than needing
a new spatula
for every dip of wax. Waste of wooden spatulas and waste tissue may be
reduced. During
use, the wax in cup 126 is maintained at a suitable warm temperature. If more
wax is
required, it can be poured from outlet 106 contamination by the wax remaining
in cup 126.
When the work is finished, the operator removes the disposable cup and
disposes it. When
the next customer arrives, a new clean disposable cup is placed in seat 124,
and new, fresh,
uncontaminated wax is poured from outlet 106. When the supply in chamber 36 is
exhausted, the pre-heated tins in modules 130, 132 are removed, opened, and
poured into
chamber 36, without having to wait a long time for the wax to melt. New
canisters 42 are
placed in seats 148 in a normal, upright position (it could be upside-down,
but it matters not
since the canister is closed). The process continues. Since the solid wax in
the canisters has
low thermal conductivity, and since operation of the heating elements is based
on the
temperature sensed adjacent inlet 104, the electrical power supplied to the
heating units will
be increased if temperature at inlet 104 falls, tending to provide greater
heating.
Alternatively, when new canisters of solid wax are placed in modules 130, 132,
the operator
may select an elevated, or maximum, heating setting to encourage more rapid
melting, and
CA 02788853 2012-09-06
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controller 174 will cut back that power setting at such time as the
temperature adjacent inlet
104 exceeds the desired target temperature hysteresis band.
If the wax is too cold, it does not flow well or apply well. If it is too
warm, it
becomes too runny, and may drip on a customer's body, which can be quite
painful. The unit
may be of substantial weight, in some embodiments more than 20 lbs or 10 kg.
In those
embodiments, more than half of the weight of the unit is aluminum. In some
embodiments
more than 1/4 of the weight is aluminum. The large thermal mass, once at the
desired steady
state temperature, may also tend to assist in maintaining an even temperature
in the wax.
Further, in a conventional approach where an open wax container is heated upon
a heating
element, as the volume of wax remaining in the container decreases, the
temperature of the
wax may tend to rise, leading, again, to the wax being too runny, and the
increased likelihood
of dripping on the customer.
What has been described above has been intended illustrative and non-limiting
and it
will be understood by persons skilled in the art that other variances and
modifications may be
made without departing from the scope of the disclosure as defined in the
claims appended
hereto. Various embodiments of the invention have been described in detail.
Since changes in
and or additions to the above-described best mode may be made without
departing from the
nature, spirit or scope of the invention, the invention is not to be limited
to those details but only
by the appended claims.
