Air filter monitoring
In a method of monitoring pollution of an air filter (Filt 1 ) in a device in which an air flow (A) generated by a fan (F) engaged by a motor (M) passes the air filter (Filt 1 ), the pollution is determined using data representative of a pressure difference (D 2 ) over the fan (F), a pressure difference (D 1 ) over the air filter, and a motor current (I) to the motor (M). The method comprises the steps of: estimating a flow through the air filter from data representative of the pressure difference (D 2 ) over the fan (F), and the motor current (I) to the motor (M), estimating a filter resistance of the air filter from data representative of the flow through the air filter, and the pressure difference (D 1 ) over the air filter, and estimating the pollution of the air filter from data representative of the filter resistance of the air filter.
1. A method of monitoring pollution of an air filter (Filt 1 ) in a device in which an air flow (A) generated by a fan (F) engaged by a motor (M) passes the air filter (Filt 1 ), wherein the method comprises the steps of:
estimating a flow through the air filter from data representative of a pressure difference (D 2 ) over the fan (F), and a motor current (I) to the motor (M), and
estimating a filter resistance of the air filter from data representative of the flow through the air filter, and a pressure difference (D 1 ) over the air filter,
estimating pollution of the air filter from data representative of the filter resistance of the air filter.
2. A method as claimed in claim 1 , wherein the pollution of the air filter is estimated from comparing the filter resistance of the air filter with a threshold value (PR).
3. A device comprising:
an air filter (Filt 1 ),
a motor (M) coupled to a fan (F) for generating an air flow through the air filter (Filt 1 ), and
a processor (MP) for determining pollution of the air filter (Filt 1 ), wherein the processor is arranged for estimating a flow through the air filter from data representative of a pressure difference (D 2 ) over the fan (F), and a motor current (I) to the motor (M),
estimating a filter resistance of the air filter from data representative of the flow through the air filter, and a pressure difference (D 1 ) over the air filter, and
estimating pollution of the air filter from data representative of the filter resistance of the air filter.
4. A device as claimed in claim 3 , wherein the processor is arranged for estimating the pollution of the air filter from comparing the filter resistance of the air filter with a threshold value (PR).