BS EN 50304:2009 pdf free download – Electric cooking ranges, hobs, ovens and grills for household use一Methods for measuring performance.
Place markings 32 mm from the measuring point of the two thermocouples according to 5.3, and
insert the thermocouples into the holes until the marking matches with the surface of the brick.
The thermocouples shall be fixed to ensure that the measuring points remain at a depth of
32 mm during the whole test procedure.
NOTE 2 The thermocouples may be fixed by means of a droplet of silicon glue at the surface of the brick or by other suitable means, see Figure 11.
NOTE 3 Due to the porosity of the brick, care should be taken that the holes of the brick are not enlarged if the thermocouples are removed and reinserted.
NOTE 4 A brick can be used for about twenty tests when handled with normal care.
8.3.1.2 Preparation
The brick, pre-treated according to 8.3.1.1, shall be prepared for energy measurement as follows.
NOTE 1 It is not necessary to pre-treat the brick between uses. It gets approximately the same water content each time it is soaked in water.
The brick shall be put into a water container so that it is completely covered with water at less than 20 °C. The water container with the brick is placed for at least 8 h into a refrigerator and cooled down to a centre temperature (both thermocouples) of (5 ± 2) °C.
A hot brick shall be cooled down in air to a centre temperature below 25 °C before putting it into the cold water.
NOTE 2 A hot brick put directly into cold water would absorb substantially more water due to the capillary effect and different water viscosity at different temperatures.
NOTE 3 Between test series, the brick should be stored in a refrigerator, preferably not soaked with water. The brick soaking water should be kept (to reduce dissolving processes); i.e. re-use of the brick storage water.
After the brick has been taken out of the water container, excessive water is allowed to drip off (for about 1 mm). Then the weight of the wet brick m shall be measured and the absorbed amount of water is determined in g taking into account the weight of the thermocouples, if appropriate, by calculating m = mw — md (md measured according to 8.3.1.1). The amount of absorbed water shall be as specified in Clause D.1. (— wet or water)
The temperature of the brick is measured. Both thermocouples shall read (5 ± 2) °C.
8.3.2 Measurement
8.3.2.1 Procedure
Three tests are performed for each heating function, as appropriate (see 3.16 to 3.18 and Table 6).
NOTE 1 In case an oven has several variants of the functions as described in 3.16 to 3.18, the manufacturer can choose the variant to be tested. This must be reported (see 8.3.4).
With the appliance at ambient temperature, according to 8.3, the brick, prepared according to 8.3.1.2, is placed in the geometric centre of the usable oven cavity with its largest surface centrally on the grid delivered with the appliance, with the thermocouples on the upper side. The grid is inserted into a shelf support level of the oven so that the centre of the brick comes as close as possible to the centre but not higher than to the centre of the usable oven cavity. The longest axis of the brick shall be parallel with the appliance front.
NOTE 2 If no grid can be purchased from the manufacturer of the appliance, any suitable grid must be used, however not a baking sheet, tin or similar.
NOTE 3 Where the grid can be inserted in two different positions (e.g. upside down gives a different height), the position should be taken that brings the brick centre closest to the cavity centre, but not higher.