JPS6318206B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a temperature control device for an electric heating device.

This type of temperature control device has a West German patent number
It is known from the specification No. 1920551. In this control device, an expansion body, that is, an expansion body communicated with a heat sensitive part through a capillary tube, is used in combination with an expansion rod, and this expansion rod performs on/off control of the electric heating device. An auxiliary contact is provided here, which is actuated manually by means of an operating bar during high-power operation and which additionally heats the expansion element during high-power operation. In this way, relatively rough control is performed during high output operation,
At low power outputs a fast and precise control to the regulated temperature is guaranteed. However, since the expansion element is heated during the first energization of the electric heating device, there is a tendency for the electric heating device to be turned off too quickly from the expansion element through the expansion body. In electric heating devices with a large heat capacity, this phenomenon does not have a very important effect. However, especially in electric heating devices with a small heat capacity, eg glass-ceramic cooking units (hot plates, etc.), the temperature control device must slowly control the temperature to the set temperature.

DE 1920553 also discloses a further temperature control device. This temperature control device has an expansion element that can be heated by starting the electric heating device, and this expansion element operates a snap switch that turns on or off electricity to the electric heating device through the expansion body, and also operates a snap switch that turns on or off electricity to the electric heating device through the expansion body. The expanding body is also affected. This causes problems similar to those described above.

The technical problem of the invention is to provide a temperature control device which allows extremely rapid temperature adjustment to a set temperature while ensuring that this set temperature is maintained by relatively uniform control. .

According to the present invention, this technical problem is solved by the essential conditions of claim 1.

According to this, control is not performed during temperature rise, but control is automatically started by the expansion body just before the set temperature in the set temperature range. Therefore, the temperature rise occurs as quickly as in the uncontrolled case. However, if the thermal response between the temperature control device and the heating section of the electric heating device is poor, a large temperature difference will also occur between the two.

For this reason, the temperature control device can only be used in contact type heating devices of glass-ceramic cooking devices, and in this case, since the glass-ceramic has poor thermal conductivity,
Correct measurement temperature cannot be obtained unless the temperature is added and compensated at a certain rate to the temperature of the contact point.
Due to the compensation of the measured temperature, this temperature control device adapts very well automatically to all conditions, so that the same control system can be used despite the extreme differences in conditions between glass-ceramic and cast hot plates. A temperature control device can be used.

Other advantages and features of the invention emerge from the embodiment claims and the description based on the drawings. Embodiments of the invention are shown in the drawings and will be explained in more detail below.

The illustrated temperature control device 11 has a main body 12 made of an insulating material such as synthetic resin or frozen stone, and the main body 12 is formed into a rectangular plate shape. A temperature control device 1 is installed in the main body 12 perpendicularly to its longitudinal direction.
A shaft 13 constituting the adjustment section 1 passes through the shaft 13, and this shaft 13 is indicated by a dashed line (FIGS. 1 and 4).
Figure) Adjustment knob 14 is attached. The dimensions of the body 12 are substantially smaller in the axial direction of the shaft 13 than in other directions.

The main body 12 is provided with recesses 16 and 17 on an operation side surface 15 spaced apart from the adjustment knob 14. A shaft 13 passes through the recess 16, and an opening/closing cam 18 of a cam switch 19 is attached to the shaft 13. The cam switch 19 has spring contacts 20,2
1, the spring contacts 20, 21 cooperate with corresponding counter contacts to provide a contact for a general pilot lamp 66 common to several electric heating devices and a contact for disconnecting the temperature control device 11. Configure. The spring contacts 20, 21 and the counter contacts are provided with plug-in terminals 25, which are designed in the form of plugs and which are connected to the operating side surface 15 of the main body 12.
stands out from

The shaft 13 passes through an adjustment knob nut 26 which, together with a left-hand thread formed in the center of the shaft 13, provides an axial adjustment of the shaft 13 for the axis of rotation of the adjustment knob 14. The nut 26 is positioned by a fastener 28, which also serves to secure the temperature control device 11 to a wall (not shown) of the electric heating device.

A snap switch 3 is located in the recess 17 of the main body 12.
2 is disposed, and this snap switch 32 extends along one side of the main body 12 over substantially the entire width of this side. The snap switch 32 has a snap spring 33.
Contacts 22 and 35 are attached to both ends of 3.

In FIG. 4, the contact 35 is on the lower surface of the spring 33 and cooperates with a counter contact located below the spring 33, while the contact 22 is on the upper surface of the spring 33 and cooperates with a counter contact 34 located above the spring 33. Work together. The operating stroke of the spring 33 is regulated by a stopper (not shown).

The spring 33 has two elastic lip pieces 36,
36 is formed by stamping, and these two lip pieces 36, 36 are supported by a support 37 while being biased downward.

The support body 37 is inserted into the notch for the lip piece 36, and the spring 33 is inserted into the both support bodies 37, 3.
There is a bridging part between 7 and 7. A protruding movable pressing point 40 of the snap switch 32 is provided at this bridging portion.

A control part 41 is arranged on the operating side 15 of the main body 12, and the control part 41 can be formed as a hollow or a bellows so as to expand and contract depending on the supply amount of inflation liquid. Expansion body 42 and transmission lever 4
It is composed of 3 and 3. The lever 43 is fixed to the main body 12 at one end. The fixed end of the lever 43 made of a highly elastic thin metal plate acts as an extremely strong leaf spring, and the lever 43 supported at both side edges is bendably connected to the main body 12 by the action of this leaf spring.

An insulating pressing body 46 is attached to the free part of the lever 43, and this pressing body 46 is connected to a spring 3 disposed perpendicularly to the longitudinal direction of the lever 43.
It is in contact with the pressing point 40 of No. 3.

An expansion body 42 is disposed directly adjacent to the lever 43 between the lever 43 and the back surface of the main body 12 or between the lever 43 and the insulating plate 45, and this expansion body 42 is fixed to the lever 43. Furthermore, the second
A connecting tube 47 is welded or soldered to the upper membrane of the expansion body 42 shown in the figure, and a capillary tube 48 is introduced into the connecting tube 47 and soldered thereto. In the area inside the connecting tube 47, the lever 43
Welded or soldered to 2.

The expansion body 42 is formed into a cap shape as a whole, and a sphere press-fitted into the shaft 13 is in contact with the opening side of the expansion body 42 . That is, due to the leaf spring action of the lever 43, the pressing point 40 between the shaft 13 and the expansion body 42 and between the pressing body 46 and the snap switch 32 is
A high surface pressure is always maintained between the Thereby, the action of the snap switch 32 is performed as described below. FIG. 1 is a mere diagrammatic representation of a snap switch.

In particular, as shown in FIGS. 2 and 3, the control unit 41
is substantially narrower than the main body 12, extends along the back surface of the main body 12 at the longitudinal center of the main body 12, and protrudes from the main body back surface by approximately the same height as the main body 12. Further, the control section 41 is covered with an insulating cap 51. The plug terminals 25 are arranged in the area of the side surface 15 and are not interfered with by the control unit 41 . The plug terminal 25 is arranged at a distance from the operating surface and therefore does not normally protrude from the control part 41.

As can be seen in particular from FIG. 4, a sensor 60 is arranged parallel to the longitudinal direction of the body 12, which consists of a tubular expansion element 61. The expansion element 61 is sheathed by an insulating sleeve 62.
2 is equipped with a control heating section 63. The sensor 60 is sheathed by a grid-like or cage-like covering cap 64, which ensures good ventilation due to its grid-like form. The cap 64 is attached to the main body 12 at a protrusion bent into a substantially V shape.
is engaged with.

The tubular expansion element 61 is closed on one side, and two capillary tubes 48 and 65 are introduced and soldered on the other side. The capillary tube 48 is connected to the expansion body 42,
The capillary tube 65 is connected to the heat sensitive part 49 of the hot plate 50. As the hot plate 50,
These include cast iron hot plates, glass ceramic hot plates or other electric cooking or heating devices.

In the circuit diagram of Fig. 1, the hot plate 5
0 is not sufficiently heated, the snap switch 32 closes its contact 35 and opens its contact 22. Therefore, current flows through the heating section 68, but no current flows through the control heating section 63. It's not flowing.

The hot plate 50 is electrically connected to the snap spring 33 of the snap switch 32 via the support 37, and is connected via the contact 21 to the power source P2. In this way, the hot plate 50
As the power is being dissipated, the auxiliary lamp 67 is also turned on, and the auxiliary lamp 67 allows the user to see whether the hot plate is currently heating the heating section 68. Regarding the amount of power, heating section 6
8 can be made 100 to 1000 times as large as the control heating section 63.

The operation of the temperature control device according to the present invention is as follows.

Before heating the hot plate, turn the adjustment knob 14 to activate the temperature control device and set the temperature control device to a certain set temperature, contacts 20 and 21 will close, and when the spring 33 is further displaced, contact 35 will close. It will be closed. This heats the heating section 68 of the hot plate.

Contact 22 is located at the opposite end of spring 33 from contact 35, so that when contact 35 closes, contact 22 opens almost simultaneously. Therefore, the expanding body 4
Under the action of 2, the contact 35 becomes the A contact, and the contact 22 becomes the B contact.
Acts as a contact point. However, contact 35 and contact 22
In the switching process, the contacts are connected one after another and temporarily go through a state in which both contacts are closed at the same time. At the start of operation of the hot plate, the contacts 22 are open, and therefore the control heating section 63 is not activated. The contacts 22 become closed due to the expansion of the expanding liquid within the heat sensitive portion 49 .

That is, just before the set temperature is reached, the contact 22 closes due to the action of the heat sensitive part 49, thereby causing the control heating part 63 to close.
is activated. As a result of the actuation of the controlled heating element 63, the expansion liquid in the expansion element 61 also expands, which additionally contributes to opening the contacts 35 through the expansion body 42 at the set temperature. The temperature difference for transitioning from conduction at the contact 35 to conduction at the contact 22 is determined by the rotation angle of the shaft 13.
Equivalent to 10 to 18 degrees. Therefore, if the shaft 13 is rotated by 10 degrees in advance, the contact 22 will become conductive with a relatively large temperature difference from the set temperature, and if the shaft 13 is rotated by 10 degrees, the contact 22 will become conductive with a small temperature difference. 22 is activated and the heating is cut off. The internal volume of the expansion element 61 is smaller than the internal volume of the heat sensitive section 49.

The heat transfer between the expansion element 61 and the heating part 63 is performed indirectly by means of an insulating sleeve 62 interposed between the expansion element 61 and the heating part 63, which allows the newly started heating to reach the initial interruption of the contact 35. will not have a major impact on Therefore, the contact point 35 is cut off only at a temperature slightly lower than the set temperature, and the temperature difference between the cutoff temperature and the set temperature is adjusted so that the temperature is raised to exactly the set temperature by the amount of temperature overshoot due to temperature inertia. .

By cutting off the contact 35, power supply to the heating section 68 and the control heating section 63 is stopped, and cooling of not only the hot plate 50 and the heat sensitive section 49 but also the expansion element 61 is started. For this reason, before the heat-sensitive part 49, which is located in the heating part of the hot plate, possibly very indirectly via the cooking pot, reaches a low temperature, the expansion element 61 and the expansion element 6
The expansion fluid in the expansion body 42 is sufficiently cooled.
The contacts 35 are then closed again. Electricity is supplied by repeating this operation, and the relative input (ratio of input time to non-input time) of this current supply is set correctly without causing the hot plate to overshoot or undershoot the set temperature. It becomes possible to maintain heating at a certain temperature.

The illustrated configuration having an expansion element connected to a fluid thermal sensitive system is just one example.
It is also possible to introduce other sensors, for example heated bimetals or expansion bars, in which case the sensor should be adapted to the current heat-sensitive system. Embodiments having a two-pole snap switch, ie a snap switch with more than one contact attached to a single snap spring, are particularly advantageous and result in low manufacturing costs. However, it is also possible to employ two separate snap switches, which would further increase manufacturing costs. Here, a hot plate with a single heating element is shown as an electric heating device. Particularly by reducing the control gain, both in glass-ceramic hot plate systems as well as in conventional cast hot plates, these hot plates have a single heating element or multiple heating elements wired in parallel. This temperature control device can be employed regardless of whether or not the device has one. Note that, for example, if the contact 22 has already cut off one of the two heating parts when it is conductive and controls only the other heating part, it is also possible to branch the heating part into two.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a temperature control device and a hot plate according to the present invention, FIG. 2 is a central vertical sectional view of the temperature control device, and FIG. 3 is a side view of the temperature control device as seen in the direction of the arrow in FIG. 4. FIG. 4 is a sectional view taken along - in FIG. 2. 11...Temperature control device, 12...Main body, 13...
...Axis, 14...Adjustment knob, 15...Side, 1
6, 17... recess, 18... opening/closing cam, 19...
Cam switch, 20, 21...Contact spring,
22... Contact, 25... Plug terminal, 26...
Nut for adjustment knob, 28... Fastener, 32...
...Snap switch, 33...Snap spring, 34...Counter contact, 35...Contact, 36...Elastic lip piece, 37...Support, 40...Movable pressing point, 41...Control unit, 42... Expanding body, 43...
Transmission lever, 45...insulating plate, 46...pressing body,
47...Joint part, 48...Capillary tube, 49...Heat sensitive part, 50...Hot plate, 51...Insulating cap, 60...Sensor, 61...Expansion element, 62
... Insulating sleeve, 63 ... Heating section, 64 ... Covering cap, 65 ... Capillary tube, 66 ... Pilot lamp, 67 ... Auxiliary lamp, 68 ... Heating section, P ₁ , P ₂ , S ... Power supply .

Claims (1)

[Claims] 1. A temperature control device for an electric heating device, especially a hot plate, comprising an expansion body 42 and a contact point 22 that influences the heating of an expansion element 61,
is in communication with the heat sensitive part 49 in the hot plate and also with the expansion element 61 heated by the electric current supplied to the control heating part 63, in which case the expansion and contraction of the expansion body 42 due to changes in the supply amount of the expansion liquid is controlled. In a temperature control device for an electric heating device, acting on an electric switch, in particular a snap switch 32, one contact 22 of the snap switch is connected to the expansion body 4.
2, the control heating section 63 of the expansion element 61 is turned on for the first time at a temperature near and below the set temperature, and is commonly shut off by the heating of the hot plate, and the snap switch 32
The other contact 35 of the snap switch is opened and closed by the expansion body 42, the other contact 35 is connected to the heating part 68, the one contact 22 is connected to the control heating part 63, and the one contact of the snap switch is connected to the heating part 68. Contact 2
2 is a temperature control device for an electric heating device, characterized in that the contact point 2 is temporarily closed at the same time as the other contact point 35. 2. The temperature control for the electric heating device according to claim 1, wherein the expansion element 61 is provided in a chamber that is thermally isolated from the expansion body 42 of the device main body 12 and the snap switch 32 and ventilated to the outside. Control device. 3 The chambers are tubularly formed, each having one capillary tube 6
5, 48 to the heat sensitive part 49 and the expansion body 42, and is surrounded by an insulating sleeve 62 which performs a heating action. Device. 4. The device according to claim 1, wherein the expansion element 61 is surrounded by an adjustment cover 64 with an opening that can be flipped up onto the device body 12. Temperature control device for electric heating equipment.