A filtering apparatus for a reflow oven includes a contaminated-gas inlet for
receiving
contaminated gas from a reflow oven; a filtering device configured to filter the
received contaminated gas; a returned gas outlet for returning filtered gas to
the reflow oven; a gas removal arrangement for allowing gas to escape from the
apparatus; and a control arrangement for controlling the rate of gas flow through
the gas removal arrangement such that in use the flow rate of contaminated gas
flowing from a hotter region of the reflow oven to a cooler region of the reflow
oven is controlled.