U.S. patent application number 09/885309 was filed with the patent office on 2001-12-27 for fryer.
This patent application is currently assigned to PALOMA INDUSTRIES, LIMITED. Invention is credited to Tateyama, Iwao.
Application Number | 20010054357 09/885309 |
Document ID | / |
Family ID | 18686883 |
Filed Date | 2001-12-27 |
United States Patent
Application |
20010054357 |
Kind Code |
A1 |
Tateyama, Iwao |
December 27, 2001 |
Fryer
Abstract
A fryer has its overheat protecting means for carrying out an
operation test properly, thus improving the utility. When it is
judged at S7 that a high limit test is in action, the procedure
goes to S10 for examining whether or not the temperature measured
by a thermistor exceeds a setting level for the test determined by
a fryer controller. If not, the combustion is continued at S11 and
the steps from S1 are repeated. When the temperature exceeds the
setting level, the procedure moves to S12 where the temperature is
controlled to stay between the setting level and the setting level
plus alpha. This is followed by turning off a high limit switch and
testing the fryer controller for displaying a high limit
abnormality.
Inventors: |
Tateyama, Iwao; (Nagoya-shi,
JP) |
Correspondence
Address: |
PEARSON & PEARSON
10 George Street
Lowell
MA
01852
US
|
Assignee: |
PALOMA INDUSTRIES, LIMITED
|
Family ID: |
18686883 |
Appl. No.: |
09/885309 |
Filed: |
June 20, 2001 |
Current U.S.
Class: |
99/330 ; 99/337;
99/403 |
Current CPC
Class: |
A47J 37/1266
20130101 |
Class at
Publication: |
99/330 ; 99/337;
99/403 |
International
Class: |
A47J 037/12; A23L
001/00; A47J 027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 21, 2000 |
JP |
2000-186784 |
Claims
What is claimed is:
1. A fryer having an oil vessel, a first temperature sensing means
for measuring the temperature of oil in the oil vessel, a
temperature setting means for setting the temperature of the oil to
a desired level, a heating means for heating up the oil vessel to
the setting level determined by the temperature setting means while
monitoring the temperature of the oil measured by said first
temperature sensing means, and a second temperature sensing means
for measuring the temperature of the oil heated by the heating
means, said fryer comprising: an abnormal stopping means for
canceling the action of the heating means, regardless of the
setting temperature, when the temperature of the oil measured by
the first temperature sensing means reaches a specified first upper
limit; an overheat protecting means for canceling the action of the
heating means when the temperature of the oil measured by the
second temperature sensing means reaches a second upper limit which
is higher than the first upper limit; and an operation testing
means for continuously actuating the heating means to carry out an
operation test for the overheat protecting means, wherein the
action of the abnormal stopping means can be prohibited while the
operation testing means is actuated.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a fryer for heating up an
oil vessel with a heating means to carry out fry cooking.
[0003] 2. Description of the Related Art
[0004] A fryer comprises an oil vessel, a heating means such as a
pulse burner for heating up cooking oil (referred to as oil
hereinafter) filled in the oil vessel, and a first temperature
sensing means such as a thermistor for sensing the temperature of
the oil in the oil vessel. The fryer also includes a first
controller provided as acting as a temperature setting means for
setting the setting temperature and the cooking time for each menu
and equipped with a control panel for controlling and displaying
the setting temperature, the menus, and so on, and a second
controller arranged responsive to a measurement of the temperature
received from the first temperature sensing means for controlling
the combustion of the heating means to maintain the oil temperature
to the setting temperature determined by the first controller.
[0005] Moreover, the fryer has a second temperature sensing means
such as a bimetal thermostat for preventing continuation of the
combustion in case that the first temperature sensing means is out
of order and its measurement is lower than the actual temperature
and an overheat protecting means for canceling the combustion of
the burner when overheating is detected. Thus the fryer also has an
operation test function for examining whether the overheat
protecting means properly operates or not. More specifically, when
a high limit switch provided in the control panel of the first
controller is turned on, it is examined whether or not the pulse
burner starts and continues the combustion until the thermostat is
switched on and stops the combustion at a predetermined temperature
when the thermostat is switched off.
[0006] As the plural controllers are communicated with each other
with a serial link system, not a parallel link system, which
decreases the number of the transmission lines, the overall
structure can be simplified. Using the serial link system may,
however, cause the setting temperature to exceed a normally
acceptable level because of wrong setting of the temperature at the
control panel of the first controller by an operator. For
compensation, an abnormal stopping means can be provided which can
cancel the combustion of the pulse burner when the thermistor
detects that the temperature exceeds a normally acceptable level.
This safety function, however, keeps the pulse burner from
continuing the combustion when the operation test for the overheat
protecting means is ordered, hence preventing the operation test
for the overheat protecting means from being performed
properly.
SUMMARY OF THE INVENTION
[0007] It is thus an object of the present invention, as defined in
claim 1, to provide a fryer which can properly carry out an
operation test for the overheat protecting means with the safety
function provided for canceling the combustion when the setting
temperature exceeds a normally acceptable level, hence improving
its utility.
[0008] For achievement of the object, the fryer defined in claim 1
of the present invention is modified having an abnormal stopping
means for canceling the action of the heating means, regardless of
the setting temperature, when the temperature of the oil measured
by the first temperature sensing means reaches a specified first
upper limit, an overheat protecting means for canceling the action
of the heating means when the temperature of the oil measured by
the second temperature sensing means reaches a second upper limit
which is higher than the first upper limit, and an operation
testing means for continuously actuating the heating means to carry
out an operation test for the overheat protecting means, wherein
the action of the abnormal stopping means can be prohibited while
the operation testing means is actuated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an overall illustrative view of a fryer;
[0010] FIG. 2 is a schematic block diagram of a control unit of the
fryer;
[0011] FIG. 3 is a time chart showing a communication action
between a fryer controller and a burner controller; and
[0012] FIG. 4 is a flowchart of a controlling action of the burner
controller.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] One embodiment of the present invention will be described
referring to the relevant drawings.
[0014] FIG. 1 is an overall illustrative view of a fryer. The fryer
1 comprises a pair of left and right oil vessels 3,3 filled with
cooking oil for frying foods (as will be described for one of the
two vessels illustrated in FIG. 1), a pulse burner 4 provided as a
heating means in the oil vessel 3 for heating up the oil, and an
oil reservoir 5 for temporarily holding the oil to be filtered,
which all are installed in a casing 2. The oil vessel 3 is also
equipped with a thermistor 6 provided as a first temperature
measuring means for measuring the temperature of the oil.
[0015] The pulse burner 4 has a combustion chamber 7 located in the
oil vessel 3 and a mixing chamber 8 located at the outside of the
oil vessel 3 and communicated with the combustion chamber 7. The
mixing chamber 8 is connected to a gas conduit 12 for feeding a
flow of fuel gas provided with, from the upstream side, an intake
electromagnetic valve 9, a main electromagnetic valve 10, and a gas
governor 11. The mixing chamber 8 is also connected to an air
supply conduit 13 provided with a blower for supply of fresh
combustion air.
[0016] The combustion chamber 7 is also communicated with a tail
pipe 14 extending through the oil vessel 3. The tail pipe 14 is
connected via a decoupler 15 at the outside of the oil vessel 3 to
an outwardly opening exhaust pipe 16. Denoted by 17 is a high
limitswitch which is a bimetal type thermostat serving as a second
temperature sensing means and mounted on an outer side of the oil
vessel 3 for measuring the surface temperature of the oil vessel 3
to be turned on and off.
[0017] FIG. 2 is a schematic block diagram of a control unit of the
fryer 1. Denoted by 20 is a first controller (referred to as a
fryer controller hereinafter) which acts as the temperature setting
means and comprises a controller circuit board 21 including a known
set of a CPU (central processing unit), ROMs, and interfaces for
exchange of data. The controller circuit board 21 is connected on
its input side to an EEPROM 22 for storage of various controlling
data. The fryer controller 20 also includes a control panel 23
exposed at the front of the casing 2 for determining and setting
the cooking menus and the cooking temperature by performing the
given operation of switches as well as displaying a selected menu
and a setting temperature.
[0018] Denoted by 24 is a second controller (referred to as a
burner controller hereinafter) which, like the fryer controller 20,
includes a CPU and ROMs and is connected to an EEPROM 25. The
burner controller 24 is also connected on its input side to the
thermistors 6,6 and the high limitswitches 17,17 located in the
paired oil vessels 3,3 respectively.
[0019] The fryer controller 20 and the burner controller 24 are
communicated to each other by a serial link system which exchanges
serial data in a polling control manner. More specifically, the
fryer controller 20 transmits a fryer controller setting data
(referred to as FSI hereinafter) including the turning on and off
of the frying action, the setting temperature, and the switching on
and off of each high limitswitch at the start of a polling period T
to demand the burner controller 24 for a response, as shown in FIG.
3. In response to the demand from the fryer controller 20, the
burner controller 24 transmits a burner controller operating data
(referred to as BSI hereinafter) including the measurements of the
thermistors 6,6 and an abnormal detection code after a given period
T1 from the end of FSI. The fryer controller 20 continues
transmission of FSI at equal intervals of T regardless of the
reception of BSI from the burner controller 24. The burner
controller 24 can transmit BSI only when receiving the demand from
the fryer controller 20.
[0020] In the fryer 1, when the start switch on the control panel
23 of the fryer controller 20 is depressed, FSI is transmitted and
received by the burner controller 24 which in turn drives the pulse
burner 4 to heat up the oil vessels 3. In response to a temperature
measurement signal from the thermistor 6, the burner controller 24
carries out the opening and closing actions of the main
electromagnetic valve 10 to turn on and off the burning action for
maintaining the temperature of the oil in the oil vessel 3 to a
setting level (normally, 93 to 182.degree. C.) determined by the
fryer controller 20.
[0021] The burner controller 24 has, in addition to the above
described heat-up controlling function, an abnormal stop
controlling function where the combustion of the pulse burner 4 is
canceled when the temperature exceeds a first higher limit higher
than the setting level, an overheat protection controlling function
where overheating, caused by the pulse burner 4 continuing its
combustion because the thermistor 6 is out of order and detects a
lower temperature than the actual temperature, is detected by the
high limitswitch 17, and an operation test controlling function
(referred to as a high limit test hereinafter) where it is examined
whether the overheat protection controlling function is properly
operated or not. Those controlling functions will now be explained
referring to the flowchart of FIG. 4. As the two, left and right,
oil vessels 3,3 are identical in the controlling manner, one of
them will only be explained.
[0022] As the start switch on the control panel 23 of the fryer
controller 20 is switched on, its switch-on signal is received at
S1. Then, it is examined at S2 whether or not any abnormal
temperature measurement derived from S6 or S9 described later is
detected by the thermistor 6. If an abnormal temperature is not
detected, the procedure goes to Step S5. When an abnormal
temperature is detected, the combustion of the pulse burner 4 is
canceled at S3 and simultaneously, an abnormal detection code is
transmitted to the fryer controller 20. When the switch on signal
is not received at S1, the abnormal detection code is reset at S4
and the combustion is canceled at S3.
[0023] This is followed by S5 where it is examined whether the high
limitswitch 17 is turned off or not. When so, the procedure
advances to S6 where it is determined that the high limitswitch 17
defects abnormality and the temperature is at an overheated level
and then returns to S1. As the abnormality is detected at S2, the
procedure goes to S3 where the combustion is canceled and the
abnormal detection code is transmitted. When it is judged at S5
that the high limitswitch 17 is turned on, the procedure advances
to S7 where it is examined whether or not the high limit test is
called for, i.e. the order for the high limit test is transmitted
from the fryer controller 20. When not, it is examined at S8
whether the temperature of the oil measured by the thermistor 6
reaches the first upper limit level of 220.degree. C. or not. When
so, it is determined at S9 that the temperature is at an
excessively higher level and the procedure returns to S1. This is
followed by turning off the combustion and the abnormal detection
code is transmitted at S3.
[0024] When it is judged at S7 that the high limit test is called
for, the procedure jumps to S10 where it is examined whether or not
the temperature measured by the thermistor 6 exceeds a setting
level of 240.degree. C. which has automatically been determined by
the fryer controller 20. When not, the procedure goes to S11 for
continuing the combustion before the steps are repeated from S1.
Then, the procedure moves to S12 where it is examined whether or
not the temperature exceeds the setting degree plus alpha (for
example, the setting level plus two degrees). When so, the
procedure goes to S13 for canceling the combustion and returns to
S1. The plus alpha is a range for avoiding the turning on and off
of the combustion from being repeated frequently. In normal, the
temperature of the oil in the oil vessel 3 is controlled to stay
within the range from the setting level to the setting level plus
alpha. When the temperature rises up to a second upper limit (230
to 240.degree. C.), the high limitswitch 17 is turned off as
described at S5. As it is judged at S6 that the abnormal detection
is transmitted, the combustion is canceled at S3. At the same time,
the abnormal detection is displayed on the fryer controller 20.
[0025] When the setting temperature is determined greater than the
second upper limit, the high limitswitch 17 is turned off and the
abnormal setting code is transferred to the fryer controller 20 to
cancel the combustion as described at S5 and S6.
[0026] According to the foregoing embodiment, not during the high
limit test, when the temperature measured by the thermistor exceeds
the first upper limit of 220.degree. C. at S8, the abnormal
detection is systematically transmitted for canceling the
combustion regardless of the setting temperature determined by the
fryer controller 20. This allows the pulse burner 4 to stop its
combustion securely and safely even if the setting temperature is
set to a wrong level by operating the fryer controller 20 by
mistake.
[0027] Also, during the high limit test, when the thermistor
measurement exceeds the first upper limit (220.degree. C.),
abnormal detection is not performed at S10, and the combustion is
continued until the detected temperature reaches the second upper
limit (230 to 240.degree. C.) at which the high limitswitch 17 is
activated. As a result, the high limit test can be carried out
properly hence contributing to the improved utility of the
fryer.
[0028] While the fryer with the plural oil vessels is described in
this embodiment, a fryer with a single oil vessel can be employed
to the present invention. The setting temperature is not limited to
the first upper limit or the second upper limit in the embodiment
but may fittingly be determined depending on the type of the
fryer.
[0029] As defined in claim 1 of the present invention, when the
temperature measured by the first temperature sensing means reaches
the first upper limit and the operation test for the overheat
protecting means is not ordered, the abnormal stopping means
receives a signal of the abnormal detection regardless of the
setting temperature determined by the temperature setting means and
stops the combustion of the heating means. Accordingly, even if the
setting temperature is set by wrong operation or the like, the
heating means can be canceled securely and safely.
[0030] Also, when the temperature measured by the first temperature
sensing means reaches the first upper limit and the operation test
for the overheat protecting means is ordered, the action of the
abnormal stopping means is prohibited and the combustion of the
heating means can be continued before the temperature measured by
the second temperature sensing means reaches the second upper
limit. As a result, the operation test for the overheat protecting
means can be carried out properly, thus improving the utility of
the fryer.
* * * * *