DE7113472U - MetaUblock thermostat - Google Patents

Description

Patents

Dr. O. Loerenbeck
Dipl.-Ing. Socks

• -ρί .-! Ng. Leesanbeck
ßielefsll Heriorder SMe 17

15/11

Gebr. Liebisch. Laboratory facilities, 4-812 Brackwede, Kulbrock-

street 2

Metal block thermostat

Ϊ The innovation "concerns a metal block thermostat, as it is called

liquid-independent heating device in laboratories for drying thermostating of analysis samples is used.

'< Such metal block thermostats have a heating block

Receiving bores for the glass vessels receiving the analysis samples, with an electrically heatable one under the heating block Floor heating plate is attached. Furthermore, such metal block thermostats are accessible either from above or from accessible from the side and then, near the floor heating plate, there is a sunk hole for the heat sensor of a contact thermometer with which the temperature control takes place. Such known metal block thermostats are practically maintenance-free, permanently operationally reliable and they work advantageously without bath fluids.

However, the disadvantage of the previously known metal block Thej? '; mostats that it is in start-up mode, i.e. when heating up the

Device, even with a metered supply of heat, the set temperature setpoint is exceeded considerably, and the setpoint only settles after a long start-up operation. Due to the structural design of a strong Sollwertüberschreitun can not avoid ζ because the upper Aussehaltpunkt the temperature controller to power

Excess of the heat source is signaled late and very delayed b ^ oriTrfc * The display ^ everz-ÖReruns: the ^ ontakttheriaomoters is particularly adversely affected by the fact that the plug-in hole in the heating block for the temperature sensor is practically like a protective tube around the sensor and thus has a retarding effect on the flow of heat. In addition, the material of the heating block present between the temperature sensor and the floor heating plate, in its not inconsiderable mass, causes a relatively sustained heat flow to the temperature sensor.

By exceeding the setpoint values, it is necessary to ^ - Your unnecessary waiting times for the target value are accepted

that are particularly long with a relatively high power requirement and thus a relatively high temperature setpoint, since the excess power of the heat source is dependent on the power requirement. Since such waiting times are often not accepted, and since there are also analysis samples that have to go through the start-up operation of the thermostat, such relatively large setpoint excesses more often cause considerable damage to the analysis samples ( overheating, or at least lead to falsifications Analysis result.

The present innovation is therefore based on the object of a metal block thermostat of the type described above To create a way in which such setpoint values are exceeded, combined with a long-term oscillation to the temperature setpoint value, can no longer occur.

The solution according to the innovation is a metal block thermostat of the type mentioned essentially in that on the floor heating plate one up into the insertion opening for The thermal bridge piece guided by the heat sensor and made of a material with a higher thermal conductivity than the heating block material is arranged. Through this thermal bridge piece, the thermal

river and over ^ ani; from the heat source to the heat sensor in optimally influenced and accelerated, which leads to that the heat sensor receives the necessary signal for switch-off precisely defined earlier. The one by the heat source Any excess power generated is thus compensated for with the power requirement of the heating block before the setpoint is reached, so that the shutdown is more controlled and precisely defined form takes place at a point in time when the setpoint in the heating block has not yet been reached. It is then at the time the heat source is switched off, the amount of heat supplied to the heating block is just high enough for the after-run f allows the inflowing heat to reach the desired temperature setpoint of the heating block. Any harmful exceedances of the temperature setpoint as well as a longer-term leveling off at the temperature setpoint come in Elimination, since the temperature now enters the temperature setpoint.

According to a preferred embodiment of the subject dev The innovation is the insertion opening in the heating block to the floor heating plate designed to be open, the thermal bridge piece between

% Heating block and floor heating plate are arranged, and the thermal bridge piece through this opening over the entire inner wall of the

** Push-in opening out, which on the one hand makes it a very simple one structural design leads, and what on the other hand, a particularly good and fast heat transfer between the floor heating plate and the heat sensor to be inserted into the opening cause + ". To such a particularly good heat conduction also contributes that, as provided according to a further preferred embodiment, the thermal bridge over the entire adjoining Extends areas of heating block and floor heating plate.

According to a further preferred embodiment, this exists Thermal bridge piece made of a metal foil, which enables a simple structural design and an inexpensive manufacturing method. Finally, it is advisable to

■ bridge piece lined insertion opening a snug fit for to give the heat sensor, so that a quick and good heat transfer is guaranteed in this area as well.

A preferred embodiment of the subject of the innovation is explained in more detail below with reference to the accompanying drawing described. Show it:

Fig. 1 shows a metal block thermostat according to the innovation in

Longitudinal section,
FIG. 2 shows a perspective individual view of the thermal bridge piece of the metal block thermostat according to FIG. 1.

The metal block thermostat has a heating block 1 made of metal, in which there are several receiving bores that are open at the top 2 for the glass vessels containing the analysis samples. On the underside of the heating block 1 is an electrical heated floor heating plate 3 attached. In the lower area of the heating block 1 there is one accessible from the side Insertion opening 4 into which the rod-shaped heat sensor of a contact thermometer, which is used for temperature control serves and with which the floor heating plate 3 can be switched on and off, can be plugged in.

Between the floor heating plate 3 and the underside of the heating block 1 a thermal bridge piece 5 consisting of a metal foil is arranged, the material of which has a higher thermal conductivity than the material of the heating block 1 has. The thermal bridge piece 5 extends over a large area over the entire adjacent Areas of the heating block and floor heating plate. The insertion opening 4 for the heat sensor is towards the floor heating plate 3 open, and through this opening 6 the thermal bridge piece 5 is guided over the entire inner wall of the insertion opening 4, so that this, together with the opening 6, is completely lined by the thermal bridge piece 5. The one with the thermal bridge piece lined Einsteckbahrung 4 is a snug fit for the

o. _t -eVer :, εο that after his insertion

he heat sensor tight: .n the corresponding, die Einstecköff- '^ - ausitieiueuueii Ber-öicii des' nannebrucköiiStuckss 5 Xicgi;

? 113472-t7.7l

Claims (5)

Protection claims 1. Metal block thermostat with a heating block, on the underside of which a floor heating plate is attached, and in which an insertion opening is provided for the heat sensor of a contact thermometer, characterized in that,
that on the floor heating plate (3) up to the insertion opening
(4) gefüh_rtes thermal bridge piece (5) made of a material with a higher thermal conductivity than the heating block material. 2. Metal block thermostat according to claim 1, characterized in that the thermal bridge piece (5) between the heating block (1)
and the floor heating plate (3) is arranged, the insertion opening (4) of the heating block (1) to the floor heating plate ^ 3) is open and the thermal bridge piece (5) through the opening (6) ί guided over the entire inner wall of the insertion opening (4) isv. 'ϊ. 3 · Metal block thermostat according to claims 1 or 2, characterized ;; characterized in that the thermal bridge piece (5) over the horny; velvet, adjacent surfaces of the heating block (1) and Floor heating plate (3) extends. 4. Metal block thermostat according to one or more of the preceding Claims, characterized in that the thermal bridge piece (5) consists of a metal foil. 5. metal block thermostat according to claims 1 to 2, characterized ^ indicates that the lined with the thermal bridge piece (5) Insertion opening (4) given a snug fit for the heat sensor is.