DE20017210U1 - Device for determining the degree of contamination of filters - Google Patents

Description

Device for determining the Degree of contamination of filters

The invention relates to a device for determining the degree of contamination of filters, in particular air filters, in a line system consisting of

- at least one electronic board equipped with components in a housing, and

- at least one optical display, preferably light-emitting diodes.

Devices of this type are known as warning indicators. These known devices measure a drop in pressure in the flow path. A negative pressure in the system is therefore registered via a pressure cell.

The disadvantage of these known devices is that they cannot be adapted to individual needs and, above all, cannot indicate the degree of contamination of the filter, but only a subjective level of contamination. After a preset pressure difference, a relay is activated and subsequent activities, such as warning signals or warning lights, are initiated.

Since different fans are used in the various systems, there are also different pressures in the lines, so an adjustment of the range is necessary.

FB-001 /Sep-00

The object of the invention is therefore to propose a device which can be adapted to limit values and indicates the degree of contamination of the filter.

The object of the invention is characterized by the solution that setting means are functionally connected to the optical display in order to set the limit values, the input variable for the setting means being an electrical variable which corresponds to the pressure difference in the system. The measured pressure drop is compared with a setpoint value and this ΔΘ is then converted into an electrical variable in a converter.

The housing is advantageously made of plastic. This also ensures that corrosion protection is guaranteed and the locations where it can be used are almost unlimited. This means that splash-proofing to IP60 is achieved, which would not be possible with a metal housing.

It is suggested to use potentiometers as an adjustment device. This has the advantage that a continuous and precise calibration to the desired limit values is possible. Some of the components on the electronic board are functionally connected to an evaluation unit in order to be able to display the measured variables converted in the evaluation unit in the desired manner. The evaluation unit supplies a current or a voltage as an output variable.

The input value of the evaluation unit is, for example, the pressure measured at the pressure sensor, which measures the pressure drop. A comparison to a setpoint is carried out in the evaluation unit. It is also conceivable, however, that pressure sensors are arranged before and after the filter element and that a pressure difference is measured in the evaluation unit.

FB-001 Sep-00

difference is determined, which is then converted into an electrical value and shown as a percentage value on the optical display. Pressure sensors, for example, can be used as pressure sensors.

The relationships are shown schematically in the drawings.
Fig. 1 shows the structure and the housing, and
Fig. 2 the measuring sensors in the flow path

Figure 1 shows the front view of the housing (1). Several LEDs (5), here 10, form a display unit for the pre-filter display (2) and the main filter display (3). Both displays are assigned a warning lamp (12, 13). The limit values, i.e. the highest and lowest values, are set using the potentiometers (6). The device can be switched on and off using the main switch (4).

Pre-filters (7) and main filters (8) are used in a line system (14), as shown in Figure 2. The pressure differences are determined here using a differential pressure cell. For this purpose, pressure sensors (9) are arranged in the flow path (11) before and after the filters (7, 8), which are connected to an evaluation unit (1), which in turn is connected to components on the electronic board in the housing (1). The pressure sensors (9) provide the respective actual pressure in the flow path (11). The pressure difference can be determined using the evaluation unit (10). Depending on the size of this &Dgr;&Rgr;, a current value or a voltage value is transmitted to components on the electronic board in the housing (1). In other words, an electrical value that is proportional to the pressure. The level of the transmitted value

·

·

·

FB-001 Sep-00

determines the deflection of the optical display, here the number of illuminated diodes (5).

Preferably 10 diodes (5) are used for each filter to enable a percentage display from 0%-100%. The potentiometers (6) are used to set the free flow path, i.e. without any degree of contamination, and thus set as the lower limit. The value therefore stands for Δ�R = 0. The upper limit is also set using one of the potentiometers (6) and stands for complete contamination of the filter (7, 8), i.e. for Δ�R = co [infinite], or very high. Using a further setting element (6), the value can be set at which the system switches to the warning position, i.e. the warning lamps (12, 13) are activated and/or the system stops, for example when the level is 80% contamination. It is of course possible to control other activities at the same time as the activation, such as triggering a warning tone or transmitting data to a central computer system. It is therefore possible, for example, to query the maintenance intervals externally.

If several filters are used as shown, when the system is switched off it is shown which filter caused this. The last value is saved and used as an input value for the filter next in the flow direction. This is necessary because when the system is switched off there would be an extremely high pressure drop and the display for the following filters would therefore be incorrect.

FB-001 Sep-00

List of reference symbols: Housing 5 1 Pre-filter display 2 Main filter display 3 Main switch 4 led 5 Potentiometer 6 Prefilter 7 Main filter 8th Pressure transducer 9 Evaluation unit 10 Flow direction 11 Warning lamp for pre-filter 7 12 Warning lamp for main filter 8 13 Flow line 14 Toggle switch 15 Differential pressure cell 16

FB-001 Sep-00

Claims (6)

Device for determining the degree of contamination of a filter, in particular an air filter, in a line system ( 14 ), consisting of - at least one electronic board equipped with components in a housing ( 1 ), and - at least one optical display ( 5 ), preferably light-emitting diodes, marked by
Adjustment means ( 6 ) functionally connected to the optical display ( 5 ) to set the limit values,
wherein the input variable for the adjustment means ( 6 ) is an electrical variable which corresponds to the pressure difference in the line system. 2. Device according to claim 1, characterized in that the housing ( 1 ) is a plastic housing. 3. Device according to claim 1, characterized in that the adjusting means ( 6 ) are potentiometers. 4. Device according to claim 2 or 3, characterized in that components on the electronic board are functionally connected to the evaluation unit ( 10 ). 5. Device according to claim 4, characterized in that the evaluation unit ( 10 ) supplies a current intensity as an output variable. 6. Device according to claim 4, characterized in that the evaluation unit ( 10 ) supplies a voltage as an output variable.