U.S. patent application number 13/298146 was filed with the patent office on 2013-05-16 for device and method for heating a pumped fluid.
The applicant listed for this patent is Reed Potter. Invention is credited to Reed Potter.
Application Number | 20130118705 13/298146 |
Document ID | / |
Family ID | 48279499 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130118705 |
Kind Code |
A1 |
Potter; Reed |
May 16, 2013 |
Device and Method for Heating a Pumped Fluid
Abstract
This system relates to a heat transfer system utilized to
transfer heat away from a fluid circulation pump for the purposes
of cooling the pump and heating the pumped fluid and is especially
useful for heating the water of a swimming pool using a water
cooled filtration pump.
Inventors: |
Potter; Reed; (Pikeville,
KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Potter; Reed |
Pikeville |
KY |
US |
|
|
Family ID: |
48279499 |
Appl. No.: |
13/298146 |
Filed: |
November 16, 2011 |
Current U.S.
Class: |
165/11.1 ;
165/104.11; 165/96 |
Current CPC
Class: |
F28D 1/0477 20130101;
E04H 4/129 20130101; F28D 1/0472 20130101; F28F 27/00 20130101 |
Class at
Publication: |
165/11.1 ;
165/104.11; 165/96 |
International
Class: |
F28D 15/00 20060101
F28D015/00; F28F 27/00 20060101 F28F027/00 |
Claims
1. A heating system for pumped fluids comprising: a. a pump, said
pump having a pump motor, a pump motor housing, pump inlet, a pump
outlet, and a fluidic heat exchanger, wherein said pump motor is
arranged in close proximity with said fluidic heat exchanger, said
fluidic heat exchanger possessing at least one fluidic heat
exchanger inlet and at least one fluidic heat exchanger outlet; b.
at least one fluid retrieval conduit for the transmission of a
fluid to said pump, said fluid retrieval conduit having a fluid
retrieval end and a pump end; c. at least one fluid transmission
conduit which functions to transmit said fluid drawn by and through
said pump to a point past said pump d. a heat exchanger inlet
conduit to conduct at least some of said fluid from said pump
outlet to said fluidic heat exchanger inlet; and e. a fluidic heat
exchanger outlet conduit to conduct said fluid from said fluidic
heat exchanger to said fluid transmission conduit.
2. The heating system of claim 1, wherein said heating system
possesses a means to control said heating system, said means to
control said system being selected from the group consisting of
manual and electronic control systems.
3. The heating system of claim 1, further comprising at least one
fluidic heat exchanger flow control valve which controls the rate
of flow of said fluid through said fluidic heat exchanger, wherein
a flow rate of said flow valve is controlled by said means to
control.
4. The heating system of claim 3, wherein said pump motor housing
possesses at least one air vent and at least one moveable air vent
cover.
5. The heating system of claim 4, wherein said at least one air
vent cover is moved by said means to control so as to allow at
least part of said vent to be covered and inhibit air cooling of
said pump motor.
6. The heating system of claim 3, further comprising at least one
temperature sensor.
7. The heating system of claim 6, wherein said at least one
temperature sensor is selected from the group consisting of contact
and non-contact sensors.
8. The heating system of claim 7, wherein said at least one
temperature sensor is arranged to measure a temperature of said
fluid within a fluid transmission circuit.
9. The heating system of claim 8, wherein said temperature of said
fluid is sensed within said fluid transmission conduit.
10. The heating system of claim 8, wherein said flow rate of said
flow valve is modified by said control means in response to said
temperature of said fluid.
11. The heating system of claim 10, wherein said fluid transmission
circuit originates and ends at a fluid reservoir.
12. The heating system of claim 11, wherein said the temperature of
said fluid is sensed within said fluid transmission conduit.
13. The heating system of claim 2, wherein said control system is
electronic and possesses programmed instructions, a machine
readable memory for storing said programmed instructions, a
display, a user interface and a means for processing said
programmed instructions read from said machine readable memory.
14. The heating system of claim 13, wherein said user interface of
said control system allows a user to input a desired fluid
reservoir temperature for use by said control system in controlling
said heating system.
15. The heating system of claim 14, wherein said control system is
programmed to achieve a desired fluid temperature in said fluid
transmission conduit by calculating optimal values for system
variables comprised of the group consisting of pump speed, fluidic
heat exchanger flow rate, and the position of at least one air vent
cover relative at least one said air vent.
16. The heating system of claim 15, wherein said speed of said
pump, said flow rate through said fluidic heat exchanger, and said
position of said at least one air vent cover are controlled by said
control system in response to said calculations.
17. A heating system for pumped fluids comprising: a. a pump, said
pump having a pump motor, a pump motor housing, pump inlet, a pump
outlet, and a fluidic heat exchanger, wherein said pump motor is
arranged in close proximity with said fluidic heat exchanger, said
fluidic heat exchanger possessing at least one fluidic heat
exchanger inlet and at least one fluidic heat exchanger outlet; b.
at least one fluid retrieval conduit for the transmission of a
fluid to said pump, said fluid retrieval conduit having a fluid
retrieval end and a pump end; c. at least one fluid transmission
conduit which functions to transmit said fluid drawn by and through
said pump to a point past said pump. d. a heat exchanger inlet
conduit to conduct at least some of said fluid from said pump
outlet to said fluidic heat exchanger inlet; e. a fluidic heat
exchanger outlet conduit to conduct said fluid from said fluidic
heat exchanger to said fluid transmission conduit; f. a means to
control said heating system, said means to control said system
being selected from the group consisting of manual and electronic
control systems. g. a flow valve to control a flow rate of said
fluid through said fluidic heat exchanger, wherein a flow rate of
said flow valve is controlled by said means to control; h. The
heating system of claim, wherein said pump motor housing possesses
at least one air vent and at least one moveable air vent cover
moved by said means to control so as to allow at least part of said
vent to be covered and inhibit air cooling of said pump motor.
18. The heating system of claim 17, wherein said fluid heat
exchanger possesses tubular channels for directing said fluid along
a heat exchanger conduction wall adjacent to said pump motor.
19. The heating system of claim 17, further comprising at least one
temperature sensor.
20. The heating system of claim 19, wherein said at least one
temperature sensor is selected from the group consisting of contact
and non-contact sensors.
21. The heating system of claim 20, wherein said at least one
temperature sensor is arranged to measure the temperature of said
fluid within a fluid transmission circuit.
22. The heating system of claim 21, wherein said at least one
temperature sensor arranged to measure the temperature of said
fluid within said fluid transmission conduit.
23. The heating system of claim 20, wherein said flow rate of said
flow valve is modified by said control means in response to said at
least one temperature sensor.
24. The heating system of claim 23, wherein said fluid transmission
circuit originates and ends at a fluid reservoir.
25. The heating system of claim 24, wherein said at least one
temperature sensor is arranged to measure the temperature of said
fluid within said fluid transmission conduit.
26. The method of heating a body of fluid by pumping said fluid
from a fluid reservoir, through a pump which directs at least part
of said pumped fluid through a fluidic heat exchanger arranged to
transfer heat from a pump motor to said fluid, then returning said
fluid directed through said fluidic heat exchanger back to said
fluid reservoir.
27. The method of claim 26, wherein said pump further consists of a
pump housing possessing at least one air vent and at least movable
one air vent cover, wherein said at least one air vent cover can be
moved to restrict air flow through said at least one air vent for
the purpose of increasing the temperature of said pump motor within
said pump motor housing so as to direct more heat to said fluid
within said fluidic heat exchanger.
28. The method of claim 26, wherein said fluid reservoir is a
swimming pool.
29. The method of claim 28, wherein said pump is a swimming pool
filtration pump.
Description
FIELD
[0001] The present system relates to heat transfer systems. More
specifically, this system relates to a heat transfer system
utilized to transfer heat away from the pump motor of a fluid
circulation pump for the purposes of cooling the pump motor and
heating the pumped fluid and is especially useful for heating the
water of a swimming pool or spa using a water cooled filtration
pump motor.
BACKGROUND
[0002] Pumps used to move fluids can generate significant heat due
to the load on their motors. This heat is generally vented to the
environment or transferred to a fluidic heat exchanger. The
transfer of heat to the environment, while unavoidable in some
applications, is inefficient since the loss of heat is the loss of
energy. If some of the heat generated by the pump motor can be
captured and used beneficially, the increase in efficiency would
yield economic benefits and result in a more environmentally
friendly system.
[0003] One application that can benefit from the capture and use of
pump motor heat is the heating of swimming pool water using a
water-cooled filtration pump using pool water recirculated back to
the swimming pool after it flows through a fluidic heat exchanger
contained within the pump motor housing. Heating a swimming pool in
this manner is not only cost effective and is a more
environmentally friendly way to heat a swimming pool, but can
effectively extend the swimming season without significant expense
from the use of additional energy resources, the purchase of
expensive heaters, and significant installation costs. Extending
the swimming season for swimmers in extreme northern and southern
latitudes is exceptionally helpful since the further one gets from
the equator, the shorter the swimming season becomes due to the
increasingly indirect angle of sunlight which is less effective at
heating a body of water and the colder air which acts to cool the
water at night.
[0004] Heating of swimming pool water is often accomplished using
natural gas and electric heating elements, both of which are costly
to operate and maintain, and must typically be incorporated into
the swimming pool design at initial construction. It would be
advantageous to simply retrofit an existing pool with a cost
effective, quiet system to heat pool water. It would also be
advantageous if the retrofitted water heating system had a neutral
carbon footprint on the environment and a neutral economic impact
on the operator.
SUMMARY
[0005] The disclosed system replaces the air-cooled swimming pool
circulating pump motor commonly found in swimming pool
installations with a water-cooled pump motor and provides a water
pickup and discharge pathway for the pool water used to cool the
pump motor. Ideally, the water temperature of the swimming pool is
monitored by a temperature sensing means such as a thermocouple or
infrared sensor so that a control means can adjust the residence
time in the system to discharge sufficiently heated water.
Alternatively, the pump could be a hybrid air-cooled and
water-cooled pump motor controlled by a control means so as to
cycle between cooling the pump with air and water to provide better
control of the swimming pool temperature and allow the pump motor
to operate without affecting the water temperature. Optionally, the
system can be combined with a solar blanket for further
efficiencies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 depicts a perspective view of a prior art swimming
pool system disclosing an air cooled circulating pump.
[0007] FIG. 2 depicts a perspective view of the swimming pool
heating system of a disclosed first embodiment incorporating a
hybrid air/water-cooled circulating pump.
[0008] FIG. 3 depicts a perspective view of the swimming pool
heating system of a disclosed second embodiment incorporating an
electronic system for sensing and controlling the hybrid
air/water-cooled circulating pump.
[0009] FIG. 4 depicts a local perspective view, taken at view arrow
4 of FIG. 3, of disclosed manually slide able covers for
selectively covering the heat-emitting vents disposed on the pump
housing.
[0010] FIG. 5 depicts a local perspective view, similar to FIG. 4,
of a disclosed alternate vent-covering embodiment incorporating an
articulating ring.
[0011] FIG. 6 depicts an exploded perspective view of an alternate,
heat exchanging embodiment, incorporating a heat exchanger tube in
a serpentine configuration winding across a conduction wall,
surrounding a fluid pump motor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] Referring now to FIG. 1, the prior art flow system
incorporates a fluid pump 20 having an electrical motor 40. The
pump motor 40 generates heat, which can be captured and utilized
instead of wasted, when operating the pump 20 due to the load
placed on the pump motor 40. Filtration of a fluid 1 stored in a
fluid reservoir 3, e.g. a swimming pool or tank, is commonly
achieved by a filter 11, e.g. a mesh screen or basket, enclosed
within a pump filtration housing 10 which receives a fluid 1 pumped
from a fluid reservoir 3 through a fluid intake conduit 5 to a pump
filtration housing inlet 15 and subsequently exits through a pump
filtration outlet 16. The fluid intake conduit 5 possesses a
reservoir end 13 submerged within said fluid 1 in the fluid
reservoir 3. Preferably the fluid 1 passes through a coarse filter
prior to entry into the pump 20 through the pump inlet 25 to
prevent clogging and/or damage to the pump 20. Some applications,
circulation of swimming pool or hot tub water, require that the
fluid also pass through a purification filter. The heat generated
by air-cooled pump motors 40 is generally lost to the environment
through a plurality of vents 44 in the pump motor housing 42. The
vents 44 allow the heated air from the pump motor housing 42 to
escape while permitting cooler air to enter as a means to regulate
the operating temperature and prevent overheating so as to extend
the life of the pump motor 40 and provide better control over the
pump motor 42 temperature.
[0013] Turning now to FIG. 2, the fluid reservoir heating system
100 incorporate a preferred embodiment, pump motor 40 which
utilizes a fluidic heat exchanger 50 in combination with vents with
articulable covers to cool the pump motor 40. Alternative
embodiments only employ fluidic cooling of the pump motor 40. A
fluidic heat exchanger 50 is arranged in close association with the
pump motor 40. Fluid 1 is circulated through the fluidic heat
exchanger 50 by directing at least part of the fluid 1 pumped from
the fluid reservoir 3 through the fluidic heat exchanger supply
conduit 56 into a fluidic heat exchanger 50 and subsequently
removing the fluid 1 and thermal energy through a fluidic heat
exchanger drain conduit 58. The fluid 1 pumped to the fluidic heat
exchanger 50 is preferably extracted from the filtered fluid 1 in
the fluid transmission conduit 7. At least one flow control valve 4
controls the flow from the pump exit 16, or alternatively the fluid
transmission conduit 7 or both, to a fluidic heat exchanger supply
conduit 56 which couples with the fluidic heat exchanger inlet 54.
A flow control valve 4 placed in the fluidic heat exchanger bypass
conduit 90 is used to control the flow of fluid 1 bypassing the
fluidic heat exchanger 50. The pump motor 40 transfers at least
part of the heat it generates to the fluid 1 resident within the
fluidic heat exchanger 50. Exemplary embodiments utilize a water
cooled pump motor 40 with no air vents and a water and air cooled
pump motor 40.
[0014] Continuing with FIG. 2, as the heated fluid 1 exits the
fluidic heat exchanger 50, heat transferred to the fluid 1 from the
pump motor 40 is removed and conducted away from the pump motor 40
and into a fluid transmission conduit 7 to be returned to the fluid
reservoir 3. Cool fluid 1 subsequently flows into the fluidic heat
exchanger 50 to replace the discharged heated fluid 1 and continue
the process of extracting heat from the pump motor 40 for
subsequent return to the fluid reservoir 3. The return of the fluid
1 heated in the fluidic heat exchanger 50 to the fluid reservoir 3
incrementally increases the temperature of the fluid 1 within the
fluid reservoir 3.
[0015] Turning now to FIG. 3, the rate of temperature change can be
controlled manually by adjusting the flow control valve 4 or valves
4 to vary the rate of fluid 1 flow through the fluidic heat
exchanger 50, but is preferably controlled by an electronic
embodiment of the control system 70 using feedback from temperature
measurement sensors 72 such as infrared thermometers, laser
thermometers, or temperature transducers, e.g. thermocouples,
thermistors, resistance temperature detectors, and integrated
circuit sensors. In a manual embodiment of the control system 70,
the temperature can be read by an operator or physically sensed by
touch to provide temperature feedback and allow the operator to act
as the manual control system and make manual adjustments to flow
rates to achieve a target fluid 1 temperature.
[0016] As best seen in FIG. 3, at least one temperature measurement
sensor 72 is placed within the fluid reservoir 3. Temperature
measurement sensors 72 are placed within the fluid intake conduit 5
and/or the fluid transmission conduit 7. Additionally, temperature
measurement sensors 72 may be placed within the fluidic heat
exchanger supply conduit 56 and the fluidic heat exchanger drain
conduit 58. Measuring the temperature difference of the fluid 1
before and after the heat exchanger 50 provides quantitative
feedback on the amount of heat being transferred away from the pump
motor 40 by the fluid 1 and permits the control system 70 to adjust
the flow control valves 4 accordingly to achieve the target fluid 1
temperature.
[0017] Various embodiments employ a flow sensor 74 to quantify the
fluid flow through the fluidic heat exchanger 50 for further
adjustment of the flow control valves 4. In various alternative
embodiments, pressure sensors 76 are installed before and
alternatively before and after the fluidic heat exchanger 50 and/or
filter to detect fouling/plugging.
[0018] The electronic control system 70 utilizes programmed
instructions which utilize feedback from the various sensors, e.g.
temperature 72, flow rate 74, and pressure 76, to control the flow
of fluid 1 through the fluidic heat exchanger 50 in an effort to
achieve a target fluid 1 temperature. Preferably, the control
system 70 possesses a display 80, such as an LCD screen, or a
switch, such as a button or rheostat type control, which permits a
target temperature to be selected. The control system 70 preferably
controls the flow control valve(s) 4 to adjust the flow of fluid 1
through the fluidic heat exchanger 50. Alternatively, the control
system 70 can control the flow of fluid 1 and/or the heat available
for exchange by affecting the speed of the fluid pump 20.
[0019] Using feedback from the temperature sensor(s) 72, the fluid
pump 20 speed and/or flow control valve(s) 4 can be adjusted to
affect the rate of heating through adjustments of residence time
within the fluidic heat exchanger 50 and/or increasing workload on
the fluid pump 20 so as to generate more heat to be transferred
away from the pump motor 40 back to the fluid reservoir 3.
[0020] As shown in FIG. 4, the pump motor housing 42 possesses
vents 44 for air cooling of the pump motor 40. The vents 44 are
preferably coverable by an articulable vent cover(s) 46 to provide
further control of the temperatures inside the pump motor housing
42. The vents 44 can be opened for running the pump motor 40 at a
cooler temperature or simply used to provide cooling when the flow
through the fluidic heat exchanger 50 is discontinued or minimized
to reduce or discontinue the heating of the fluid 1 in the
reservoir 3. Ideally, the articulable vent cover(s) 46 is
controlled by the control system 70 to optimize the temperature
within the pump motor housing 42, provide better control over the
rate of fluid 1 heating, and to stabilize the fluid 1
temperature.
[0021] A beneficial example of the method of heating a circulating
fluid 1 using waste heat from the fluid pump motor 40 is the
heating of swimming pool, hot tubs, and spa water. Swimming pools
undergo frequent or almost continuous filtration. The pool water is
typically drawn from the pool through a basket filter 11 before
entering the pump 20 and subsequently being returned to the pool
after passing through a purification filter. The pump motor 40
generates significant heat which is vented to the environment
through air vents 44 in the pump motor housing 42. Capturing the
waste heat by redirecting at least part, and potentially all of the
filtered recirculated pool water back to the pump 20 for use in a
fluidic heat exchanger 50 which transfers heat from the pump motor
40 serves to both cool the pump motor 40 and heat the pool
water.
[0022] Yet another example is the use of the system to heat a
fluid, such as lubricant or base oil, as it is transferred from an
outside tank to an indoor switching and pumping area for filling of
packaging or blending with additional components. The lubricant or
base oil could undergo gelation or significant wax crystal
formation which would prevent transfer of the fluid or cause pump
failure due to cavitation and the creation of a vacuum within a
transfer line. Heating of the lubricant or base oil could improve
cold temperature pumpability without requiring mechanical breakup
of cold induced gels or wax crystal formations or the application
of electrical heating jackets to transfer lines.
[0023] The water in swimming pools is typically heated by solar
radiation. The rate of heating can be increased by the use of a
common solar blanket. The use of a solar blanket in combination
with the system 100 and method detailed above increases the rate of
heating and decreases heat loss resulting from evaporation or
direct contact with the cool night air. Other methods of heating
the water in swimming pools include natural gas and electric
heaters, both of which consume increasingly scarce natural
resources. The disclosed system 100 and method have the advantage
of being carbon neutral. The system 100 also eliminates much of the
expense of retrofitting swimming pools without preexisting heating
systems since replacing the pump motor 40, routing the fluid 1
through a fluidic heat exchanger 50 and its associated inlet 54 and
outlet conduits 52, and placing the sensors 72, 74 and 76 is all
that is required.
[0024] The use of sensors 72, 74 and 76 allows the use of a closed
loop control system 70 or feedback controller 70. Preferably, the
sensor 72, 74 and 76 outputs are fed back through to the control
system 70 for comparison to a reference value. The control system
70 can be arranged as a single-input-single-output, i.e. SISO,
control system or as a multi-input-multi-output, i.e. MIMO, control
system. A preferred feedback control design is the PID controller,
i.e. proportional-integral-differential controller. If u(t) is the
control signal sent to the system, y(t) is the measured output and
r(t) is the desired output, and the tracking error is
e(t)=r(t)-y(t), a PID controller has the general form:
u ( t ) = MV ( t ) = K p e ( t ) + K i .intg. 0 t e ( .tau. ) .tau.
+ K d t e ( t ) ##EQU00001##
wherein: K.sub.p: Proportional gain K.sub.i: Integral gain K.sub.d:
Derivative gain
t: Time.
[0025] A PID controller calculates an error value as the difference
between a measured process variable and a desired set point. The
PID controller attempts to minimize the error by adjusting the
process control inputs. The PID controller is preferably controlled
by commercially available PID tuning and loop optimization
software. Alternatively, a PI controller, i.e.
proportional-integral controller, is used. A PI controller is
similar to a PID controller, but without using a derivative of the
error. A PI controller is useful to keep the fluid 1 temperature
steady when sensor data is noisy.
[0026] As best seen in FIG. 5, the fluid 1 temperature can be
controlled manually by repositioning the vent cover 57 relative to
the air vents for the hybrid air cooled/water cooled pump motor 40.
The vent cover(s) 57 is preferably controlled by the control system
70 in response to temperature data collected by the previously
discussed temperature sensors. In an alternative embodiment the
vent cover 57 is actuated by a solenoid or similar means and slides
or rotates into place over the pump motor housing 42 to cover the
vents 44 as desired. In a still further embodiment, the fluid 1
temperature can be controlled manually by adjusting the flow rate
through the fluidic heat exchanger 50 that cools the pump motor 40
in the water cooled pump motor 40 or in the hybrid air cooled/water
cooled pump motor 40 by adjusting the flow control valve(s) 4
arranged before and/or after the fluidic heat exchanger 50.
Adjusting the volumetric rate of the pump 20 also provides a way to
control the temperature of the fluid 1 since increasing the load on
the pump 20 would yield more thermal energy for recapture and
transfer to the fluid reservoir 3 or swimming pool by way of the
fluidic heat exchanger 50.
[0027] While the internal configuration of the fluidic heat
exchanger may take a number of configurations, FIG. 6 shows a
preferably tubular passage winding across a fluidic heat exchanger
conduction wall 55 of the fluidic heat exchanger 50 that is in
contact or close proximity with the pump motor 40 within the pump
motor housing 42. Inside the fluidic heat exchanger 50, the fluid 1
flow is either turbulent or laminar. Turbulent flow produces better
heat transfer, due to the mixing of the fluid 1 which results in
better dispersion of the heat throughout the fluid 1. Laminar-flow
heat transfer relies entirely on the thermal conductivity of the
fluid 1 to transfer heat from inside a stream to a fluidic heat
exchanger 50 wall. An exchanger's fluid 1 flow can be determined
from its Reynolds number (NRe):
N Re = .rho. .times. V .times. D .mu. ##EQU00002##
Where V is flow velocity and D is the diameter of a tube in which
the fluid flows. The units cancel each other, making the Reynolds
number dimensionless. If the Reynolds number is less than 2,000,
the fluid flow will be laminar; if the Reynolds number is greater
than 6,000, the fluid flow will be fully turbulent. The transition
region between laminar and turbulent flow produces rapidly
increasing thermal performance as the Reynolds number increases.
The type of flow determines how much pressure a fluid loses as it
moves through a heat exchanger. This is important because higher
pressure drops require more pumping power which affect pump
operating conditions and may require a larger pump than would
commonly be used in a particular pumping application.
[0028] Laminar flow produces the smallest loss, which increases
linearly with flow velocity. For example, doubling the flow
velocity doubles the pressure loss. For Reynolds numbers beyond the
laminar region, the pressure loss is a function of flow velocity
raised to a power in the range 1.6-2.0. In other words, doubling
the flow could increase the pressure loss by a factor of four. The
pressure loss is accounted for in the selection of the appropriate
pump and is a skill known to those skilled in the art of fluid
mechanics. In embodiments incorporating air vents 44 in the pump
motor housing 42, the fluidic heat exchanger is configured and
arranged so as to not block the vents 44 or otherwise interfere
with their function.
[0029] It is the inventor's intention that, although numerous
alternative embodiments may be derived from this disclosure by
those seeking to understand and replicate the inventor's system and
method, such configurations that do not stray from the principles
disclosed and claimed herein are not disclaimed but should be
viewed as equivalents which also fall within the patent claims of
the inventor.
[0030] Additional objects, advantages and other novel features of
the invention will be set forth in part in the description that
follows, and in part will become apparent to those skilled in the
art upon examination of the following, or may be learned with the
practice of the invention. The objects and advantages of the
invention may be realized and attained by means of the
instrumentalities and combinations particularly pointed out in the
appended claims.
* * * * *