DE29701561U1 - Test device for temperature control elements - Google Patents

Description

KERN, BREHM & PARTNERS

Civil law partnership (GbR) Albert-Rosshaupter-Sfr. 73 - D - 81369 Munich - Telephone (089) 760 5520 760 55 26 - Fax (089) 760 55 59

Chang-9071/GM 30 January 1997 vp-pw Jui-Pinlin No. 1, Lane 143,

Chung-Shan Road, Ren-Te Shiang, Tainan Shien, Taiwan, ROC

Test device for temperature control elements

The invention relates to a testing device for one or more temperature control elements, which device is contained in particular in an internal cavity of a table and has a heat conducting plate, a heat transfer fluid and a test plate on which the at least one temperature control element is arranged for testing purposes and is heated evenly and evenly in order to carry out the testing carefully and quickly.

Completed temperature control elements generally need to be tested to determine whether or not the control elements have correct thermal sensitivity, proper function and operational safety. To date, no comparatively accurate test equipment for temperature control elements is available, so that a large number of temperature control elements are put on the market without effective testing, thereby exposing the lives and property of users to potential danger.

A conventional testing method uses a table with an electric heater and a test device for displaying the heat supplied to a temperature control element. Since a heater itself generates heat in an unbalanced state and the heat reaches the temperature control element placed on the surface of the table in an uneven or unbalanced state, the element cannot be tested thoroughly. In addition, the number of elements to be tested at one time is only about 20.

OSWJ7JADCC

The invention is based on the object of creating a testing device for temperature control elements with which precise test results can be achieved.

This object is achieved according to the invention by a testing device having the features of claim 1.

Advantageous further training is the subject of the dependent claims.

A main feature of the invention is to provide a test device which has a heating device, a heat conducting plate on the heating device, a lower housing arranged on the heat conducting plate with an inner cavity, a heat transfer fluid contained in the inner cavity of the lower housing, an upper housing provided on the lower housing with an inner cavity, a test plate provided in the upper housing on which the at least one temperature control element is arranged and the bottom of which is immersed in the heat transfer fluid for testing the thermal properties, and an upper cover closing the upper housing.

Another aspect of the invention relates to an indicator lamp section provided on an operating panel. Indicator lamps mounted on the indicator lamp section may be illuminated or remain off to indicate whether or not the temperature control elements under test are reaching the maximum temperature setting.

An embodiment of the invention is explained in more detail below with reference to the drawing. They show:

Fig. 1 is an exploded perspective view of a test device for a temperature control element;

Fig. 2 is a perspective view of the test device for a temperature control

element;

Fig. 3 is a partially sectioned front view of the test device for a temperature control element;
35

Fig. 4 is a circuit diagram of the test device for a temperature control element;

Cf-ttSflf IAOOC

Fig. 5 is a plan view of the test device for a temperature control element operating under test conditions;

Fig. 6 is a side view of a temperature control element (a bimetal temperature controller) which is mounted on a test plate of the test device for a temperature control

element is arranged, with no control lamp lighting up to indicate that the (heated) has been heated to the test temperature; and

Fig. 7 is a side view of a temperature control element (the bimetal temperature controller) which is mounted on the test plate of the test device for a temperature control

element, with an indicator lamp lighting up to indicate that the element is in the warm-up state but has not yet been heated to the specified highest temperature.

A preferred embodiment of the invention is shown in Fig. 1 and comprises a table 1 and a testing device 2 connected to the table

The table 1 has an inner cavity 10 surrounded by a bottom wall, four side walls and an open top, a layer of heat-retaining cotton 11 fixed to the bottom wall and the four side walls, a flat intermediate plate 12 supported by a frame in the inner cavity 10, a vertical rear control panel 13 extending upward from the rear wall, a control lamp section 130 and two temperature control switches 131, 132 provided on the front of the control panel 13, a cooler 14 fixed to the control panel 13 and inclined downward toward the inner cavity 10 for cooling the test device 2, and two hinged plates 15, 16 pivotally connected to opposite sides of the open top of the table 1, respectively.

The test device 2 is provided in the inner cavity 10 of the table 1 and has an electric heating device 20 provided on the flat intermediate plate 12, a heat conducting plate 21 arranged on the heating device 20, a lower housing 22 arranged on the plate 21 with an open upper side, a heat transfer fluid 23 contained in the lower housing 22, an upper housing 24 arranged on the lower housing 22, a test plate 25 provided in the upper housing 24 and an upper cover 26 closing the upper housing 24.

The heat conducting plate 21 is made of metal, such as aluminum, copper, iron, i.e. of a material with good heat transfer properties.

The base housing 22 is made of a metal with good heat transfer properties and has a bottom surface which is in contact with the top surface of the heat conducting plate 21 , an inner cavity 220 which is surrounded by the bottom wall and four low side walls , four short upper side walls 221 extending upward from the upper edges of the four low side walls, cable holes drilled in a low side wall 22 and a temperature controller attached to an inner surface of a low side wall 223.

The heat transfer fluid 23 is contained in the inner cavity 220 of the lower housing 22. The fluid does not contain any toxic substances, is odorless, non-flammable and has good thermal stability, good oxidation resistance and long shelf life. It consists, for example, of petroleum, silicone oil, etc. with good heat transfer properties.

The upper housing 24 is made of a metal with good heat transfer properties. It is placed in the upper side walls of the lower housing 22 on the inner cavity 220 and has an open top, an open bottom, four laterally projecting edges 240 which extend laterally away from the upper ends of the four side walls of the upper housing 24, and cable holes 241 provided in a side wall which correspond to the cable holes 222 of the lower housing 22.

The test plate 25 is welded to the lower ends of the four side walls of the upper housing 24 and has a temperature controller 250, several clamps 251 and several sockets 252 on its upper surface.

The upper cover 26 closes the top of the housing 24 including the four protruding, lateral edges 240 of the upper housing.

The assembly of the test device according to the invention is explained in more detail below with reference to Figs. 1 to 4.

First, the heating device 20 is arranged on the intermediate plate 12 in the inner cavity 10 of the table 1, whereby highly heat-resistant lines 200, such as a glass fiber insulated line, a silicone gel insulated line, a Teflon insulated line, the heating device

device 20 and the circuit breaker together. Then, the heat conducting plate 21 is attached to the heating device 20, and the bottom of the base housing 22 is placed directly on the top of the heat conducting plate 21 so that the bottom of the base housing 22 is in contact with the surface of the heat conducting plate 21. The upper side walls 221 are arranged around the opening of the inner cavity 10 of the table 1.

The heat transfer fluid 23 is then poured into the inner cavity 220 of the lower housing 22 and the upper housing 24 is arranged around the four upper side walls 221 of the lower housing 22 in the inner cavity 220. The test plate 25 is now welded to the lower ends of the four side walls of the upper housing so that the bottom of the test plate 25 can be immersed in the heat transfer fluid 23, the four protruding side edges 240 of the upper housing 24 being supported by the four upper side walls 221 of the lower housing 22 and the cable holes 241 being aligned with the cable holes 222 of the lower housing 22.

The upper cover 26 is then placed on the four protruding side edges 240 of the upper housing 24 so that the upper opening of the upper housing is closed.

The high heat-resistant wires of the temperature controllers 250, 223 such as PID temperature controllers used in microcomputers in the inner cavity 220 of the lower case 22 are passed through the wire holes 241, 222 of the upper case 24 and the lower case 22 and are connected to the temperature control switches 131 and 132 on the operation panel 13, respectively, so that the test temperature can have an accurate temperature comparison value and that the highest and lowest temperature limit specifications can be set. In addition, a temperature protection device is provided in the table 1 to prevent accidents due to excessive temperatures. Furthermore, the conductive socket 252 is connected to the control lamp section 130 of the control panel 10 via high temperature resistant wires which are laid through the holes 242 and 222 of the lower and upper housings 22, 24 such that a single lamp can light up when a temperature control element A is connected to the conductive socket 252 for test purposes.

To test a temperature control element, such as a bimetallic temperature switch, as used in a herb boiling pot or a hot water device, or a magnetic temperature spring switch, as used in an electric rice cooker, it is placed on the test plate 25, with the clamping devices 251 holding the element and the heat-resistant leads of the element being connected to the conductive

Gf-4\3Grtrt.CQC

Socket 252 is connected as shown in Fig. 5. Then, the heater 20 is energized so that the heat conducting plate 21 gives off heat to the heat transfer fluid 23 in the inner cavity 220 of the lower housing 22, whereby the lower housing 22 is not heated directly if the fluid 23 should undergo a chemical transformation and thus a change in its properties due to instantaneous overheating. Since the fluid 23 gives off the heat to the upper housing 24 in contact with the fluid in a uniform and balanced state, the test plate 25 absorbs the heat in the same state. When the upper cover 26 rests on the test plate 25 and the upper housing 24, the heated temperature control member A will cause the pilot lamp to turn off when the member A has reached the predetermined highest temperature as shown in Fig. 6.

If the temperature of element A drops or does not reach the preset maximum temperature value, the indicator lamp will light up as shown in Fig. 7. Thus, the upper limit and lower limit of element A can be indicated by turning the indicator lamps on and off, respectively. If the difference between the highest and lowest temperatures is within the preset value, element A is in a normal state. If the difference is outside the preset value, element A is faulty.

The temperature control switches 131 and 132 are used to set the upper and lower temperature limits for different temperature control elements. In addition, the cooler 14 can be used to cool the temperature control elements being manufactured during the testing process, thereby speeding up the testing process and reducing the testing time. The folding plates 15, 16 can be used to temporarily put down the temperature control elements to facilitate work.

The invention described in the above description has the following advantages:
30

1. The cotton layer 11 provided around the inner cavity 20 retains the heat generated by the heating device 20 so that it cannot escape from the inner cavity 10 and enables accurate testing of the temperature control element(s);

2. the heat transfer fluid 23 is not subjected to any chemical transformation caused by instantaneous overheating and therefore does not change its properties.

CHA9O71AD0C

shafts so that the test accuracy can be maintained because the heat conduction plate 21 is arranged between the heater 20 and the lower housing 22 and the lower housing 22 is not directly heated by the heater 20;

3. Thermal energy can be transferred from the heat transfer fluid 23 to the test plate 25 in a uniform and balanced manner, and thus thorough testing of numerous temperature control elements can be carried out simultaneously;

4. High heat-resistant wires are used to connect the heater 20, the conductive bushings 252 and the temperature controllers 223, 250, so that there is no fear of burning the wires;

5, the cooler 14 provided above the table 1 can quickly cool down the temperature control elements being tested while they are still in a hot state, thereby effectively accelerating the testing.

The invention has been described above with reference to a preferred embodiment. It is to be understood that numerous modifications may be made and that the appended claims are intended to cover such modifications as fall within the scope of the invention.

Claims (5)

KERN, BREHM & PARTNERS Civil law partnership (GbR)
Albert-Rosshaupter-Str. 73 - D - 81369 Munich - Telephone (089) 760 55 20 760 55 26 - Fax (089) 760 55 59 Chang-9071/GM January 30, 1997 vp-pw Jui-PinLin No. 1, Lane 143, Chung-Shan Road, Ren-Te Shiang, Tainan Shien, Taiwan, ROC Test device for temperature control elements Protection claims
15 1. Test device for at least one temperature control element (A) ₅ comprising: a table (1) with an open top and an interior cavity (10) enclosed by a bottom wall and four side walls;
20 a testing device (2) arranged in the inner cavity (10) of the table (1), which has: - a flat heating device (20);
25 - a heat conducting plate (21) arranged on the heating device (20); - a base housing (22) having an open top, a bottom wall and four side walls and an ion cavity (220) defined by the bottom wall and the four side walls, the bottom wall being in contact with the top of the heat conducting plate (21); - a heat transfer fluid provided in the internal cavity (220) of the lower housing (22) (23); - an upper housing (24) having an open top, an open bottom and four side walls supported on an upper portion of the lower housing (22); - a flat test plate (25) which is welded to the lower ends of the four side walls of the upper housing (24) and whose bottom is immersed in the heat transfer fluid (23); — an upper cover (26) closing the open top of the upper housing (24), characterized in that the heating device (20) can be heated electrically, that the heat conducting plate (21) heated by the heating device (20) transfers the heat in a uniform and balanced manner to the heat transfer fluid (23) in the lower housing (22), and that the heat transfer fluid (23) transfers the heat in a uniform and balanced manner to the test plate (25) such that at least one temperature control element (A) can be heated to the set upper and lower temperature limits for testing the temperature control properties of the at least one temperature control element in an accurate and rapid manner. 2. Testing device for at least one temperature control member according to claim 1, characterized in that a layer of cotton (11) is provided on the inner surfaces of the four side walls and the bottom wall of the inner cavity (10) of the table (1) for keeping the heat inside the inner cavity, that a flat intermediate plate (12) with frame is provided in the inner cavity (10), that an operating panel (13) extends upwards from the rear wall of the inner cavity (10) and has a control lamp section (130) with a plurality of control lamps and temperature control switches (131, 132), that a radiator (14) provided on the operating panel (13) and inclined forwards is provided, and that a flat, foldable plate (15, 16) is provided on two opposite sides of the opening of the inner cavity (10) of the table (1). 3. Test device for at least one temperature controller according to claim 1 or 2, characterized in that the inner cavity (220) of the lower housing (22) and the test plate (25) each have a temperature controller (223, 250). 4. Test device for at least one temperature control element according to one of the preceding claims, characterized in that the lower housing (22) has four upper side walls (221) which extend upwards from the upper ends of the four side walls surrounding the inner cavity (220), that one of the four side walls has cable holes (222), that the upper housing (24) has four projecting side edges (240) at the upper ends of the four side walls, and that one of the four side walls of the upper housing (24) has cable holes (241). 5. Test device for at least one temperature control element according to one of the preceding claims, characterized in that the test plate (25) has a plurality of clamping devices (251) and a plurality of conductive sockets (252) on the upper side.