DE102013008178A1 - Scale with temperature compensation - Google Patents

Abstract

Scales with load pick-up (5), characterized in that a thermoelectric element (10), which prevents temperature influences on the scales, is attached between the load pick-up (5) and the weighing item.

Description

State of the art

High-precision balances in industrial environments are subject to thermal influences. In particular, the inclusion of the sample transfers heat energy through the housing walls through the mechanics and electronics of the balance. Even the smallest amounts of heat introduced influence the accuracy of the balance.

These influences are exacerbated at elevated temperatures of the sample. In particular, in the industrial production of products, the sample has some process due to a high temperature. Thus, with the number of weighing processes, the heat energy introduced increases and the balance increasingly loses its precision.

Even devices mounted between the scale and weighing goods, such as conveyor belts, introduce heat energy into the balance. By friction of the conveyor belt and the drive motor required for the belt heat is generated and transported by heat conduction via the load receiving in the housing of the balance.

Insulating materials between the goods to be weighed and load suspension or between mounted devices and load bearing can reduce the heat flow, but not completely interrupt it. Thus, the negative effect on the precision of the scale is indeed reduced and / or time-delayed, but not eliminated.

With manual handling of the weighing sample, the balance can be adjusted in each case between the weighing operations so that the reduction in precision is at least partially eliminated. Especially with automatically loaded scales or such scales that are involved in a conveyor belt-based manufacturing process, such an interruption for readjustment is often not possible or not desirable.

task

Object of the present invention is to improve the precision of a balance with temperature influences on the load bearing without requiring readjustment.

Presentation of the invention

The object is achieved in conjunction with the features of protection claim 1, characterized in that between the load bearing on the balance and other attachments such as pan or conveyor belt, a thermoelectric element is mounted, the cooling side with the load bearing and the warming side with the appropriately mounted attachment connected is.

To derive the additional heat generated by the thermoelectric element, a heat sink may be mounted on the warming side, in which the heat is released by convection to the environment.

With very cold weighing material, the cooling side and the warming side of the thermoelectric element can be interchanged during assembly, so that on the one hand the scale is not too cold, on the other hand, the sample is not heated too much.

To improve the precision of this device, a temperature sensor can be mounted on the load bearing of the balance, which fulfills the function of a thermostat, which regulates the performance of the thermoelectric element. This allows the temperature of the load bearing of the balance to be reliably influenced.

To further improve the precision of the device, an additional thermal insulation may be mounted between the thermoelectric element with temperature sensor and the load receiver, so that large parts of a heat energy flowing in the direction of load absorption can be absorbed by the cooling side of the thermoelectric element before the thermal energy dissipates the thermal energy Isolation permeates.

In order to reduce the required power of the thermoelectric element, a thermal insulation can be mounted between it and the additional attachments.

Brief description of the drawings

In the drawings show:

1 FIG. 2: a schematic section of a balance with weighing pan mounted on the load receiver, without a thermoelectric element (prior art), FIG.

2 FIG. 2: a schematic section of a balance with a conveyor belt mounted on the load receiver, without a thermoelectric element (prior art), FIG.

3 FIG. 2: a schematic section of a balance with thermoelectric element mounted on the load mount and conveyor belt mounted thereon, and FIG

4 : A schematic section of a balance with mounted on the load-bearing thermal insulation, then mounted thermoelectric element, heat sink and conveyor belt.

Description of the embodiments

In the case 1 The scales are weighing mechanics 3 and weighing electronics 4 accommodated. By means of the load suspension 5 the weight of the cargoes through the housing feedthrough 2 through to the car mechanics 3 transfer. On the load suspension 5 can accordingly 1 and 2 Attachments like weighing pan 6 or conveyor belt 7 be mounted. 1 and 2 show conventional scales without thermoelectric element.

The load pickup 5 can be done accordingly 3 be interrupted by a thermoelectric element, which further ensures the transmission of the weight, but the flow of thermal energy from the weighing material 9 over the load suspension 5 counteracts the interior of the balance. The temperature sensor 13 acts as a thermostat on the performance of the thermoelectric element 10 , So can the temperature on the cooling side 12 of the thermoelectric element 10 kept constant.

Between load pickup 5 and thermoelectric element 10 can be done accordingly 4 a thermal insulation 15 be mounted so that one from the temperature sensor 13 perceived temperature increase largely by the thermoelectric element 10 can be compensated before the thermal energy thermal insulation 15 penetrates and heating the load bearing 5 causes.

On the warming side 11 of the thermoelectric element 10 can accordingly 4 Heat sink attached to you by friction of the conveyor belt 7 , Drive motor 8th and thermoelectric element 10 transferred thermal energy by convection to the environment.

LIST OF REFERENCE NUMBERS

1

Housing of the balance

2

Housing bushing

3

wage mechanics

4

wage electronics

5

lifting

6

pan

7

conveyor belt

8th

drive motor

9

Wägegutaufnahme

10

thermoelectric element

11

warming side

12

cooling side

13

temperature sensor

14

Adapter with temperature sensor

15

thermal insulation

16

heatsink

Claims (10)

Scale with load suspension ( 5 ), characterized in that between load bearing ( 5 ) and weighing a thermoelectric element ( 10 ), which prevents temperature influences on the balance. Balance according to claim 1, characterized in that the power of the thermoelectric element ( 10 ) by means of a temperature sensor ( 13 ) can be regulated. Scales according to one of the preceding claims, characterized in that on the warming side ( 11 ) of the thermoelectric element ( 10 ) Heat sink ( 16 ) are attached, the heat energy to the environment. Scales according to one of the preceding claims, characterized in that between cooling side ( 12 ) of the thermoelectric element ( 10 ) with temperature sensor ( 13 ) and load bearing ( 5 ) a thermal insulation ( 15 ) is attached. Scales according to one of the preceding claims, characterized in that the cooling side ( 11 ) and warming side ( 12 ) of the thermoelectric element ( 10 ) are reversed so that the influence of low temperatures on the balance is prevented. Balance according to one of the preceding claims, characterized in that the thermoelectric element ( 10 ) is formed as a Peltier element. Scales according to one of the preceding claims, characterized in that by means of electronic control in operation, the cooling side ( 12 ) and the warming side ( 11 ) of the thermoelectric element ( 10 ) can be reversed. Scales according to one of the preceding claims, characterized in that between the thermoelectric element and weighing material is mounted a thermal insulation, so that the required power of the thermoelectric element ( 10 ) can be reduced. Scales according to one of the preceding claims, characterized in that the thermoelectric element ( 10 ) was mounted by means of adhesive, so that no screws or bolts as thermal bridges the thermoelectric element ( 10 ) penetrate or bypass. Balance according to one of the preceding claims, characterized in that a plurality of thermoelectric elements are combined.

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