The invention relates to a method for supplying at least water and liquid yeast to a mixing chamber, wherein the temperature of the water is controlled in dependence on the temperature which is desired in the mixing chamber, whereupon said water and said yeast are supplied to said mixing chamber from a water metering device and a liquid yeast metering device respectively, after which flour is mixed with said liquid yeast and said water in said mixing chamber.

The invention furthermore relates to a device comprising at least a water metering device and a liquid yeast metering device, which are each in communication with a mixing chamber via a pipe.

With a similar method, which is known from German patent application DE-A1-30.23.823, flour, among other things, is mixed with liquid yeast and water, which are each supplied to the mixing chamber in a predetermined quantity. The yeast is preferably in liquid form, since this makes it easier to meter the desired quantity. Liquid yeast must be stored at a relatively low temperature of about 4 °C in order to inhibit the action of the yeast. Only at the moment when the liquid yeast is added to the flour, whereby the flour has a temperature of for example 10-22 °C, does the liquid yeast become active.

One drawback of supplying liquid yeast is the fact that yeast remains behind in the pipe between the cooled yeast metering device and the mixing chamber, which pipe is at room temperature. There is a risk thereby of the liquid yeast becoming active in said pipe. This can be prevented by cleaning the pipe regularly, which takes up a relatively great deal of time. Another drawback is the fact that less than the desired quantity of yeast is supplied to the mixing chamber as a result of yeast remaining behind in the pipe.

The object of the invention is to provide a method wherein a desired quantity of liquid yeast is supplied to the mixing chamber, whilst hardly any residue will remain behind in the pipe.

This objective is accomplished with the method according to the invention in that the pipe which is connected to said liquid yeast metering device is coupled by means of a coupling near said liquid yeast metering device to the pipe which is connected to said water metering

device, and that said metering devices are in communication with said mixing chamber from said coupling via a common discharge pipe, wherein first the liquid yeast is supplied to the mixing chamber, followed by the water, wherein residue of said liquid yeast which is present in said discharge pipe is removed from said discharge pipe by means of said water and supplied to the mixing chamber.

In this manner the yeast is washed out of the discharge pipe by the water. Furthermore, said water is at the same time supplied to the mixing chamber, so that the residue of the yeast is introduced into the mixing chamber as yet.

The temperature of the water is determined in dependence on the amounts of said water and said yeast and on the temperature of said yeast, among other things, so that the mixture in the mixing chamber will have a desired temperature. It is also possible, of course, to take into account the temperature of other substances present in the mixing chamber.

It is noted that from European patent application EP-A2- 0.172.000 a method is known wherein residue of a fluid which is present in a pipe is discharged by means of water. Said patent application does not relate to the mixing of water, liquid yeast and flour in desired amounts and at a predetermined temperature in a mixing chamber, however.

Moreover, the device required for carrying out said method is relatively complicated, inter alia because of the presence of two distribution units 36,42.

Another object of the invention is to provide a device wherein the problems of the known device are avoided.

This objective is accomplished with the device according to the invention in that the pipe which is connected to the liquid yeast metering device is coupled by means of a coupling near said liquid yeast metering device to the pipe which is connected to the water metering device, wherein said metering devices are. in communication with the mixing chamber from said coupling via a common discharge pipe.

The yeast from the yeast metering device can be cleared from the discharge pipe, via the common discharge pipe, by means of the water from the water metering device, whereby at the same time the water is supplied to the mixing chamber. In this way it is no longer necessary to clean the discharge pipe regularly, and it is ensured that the desired quantity of the yeast is supplied to the mixing chamber.

The invention will be explained in more detail hereafter with reference to the drawings, wherein: Figure 1 is a diagrammatic representation of a device according to the invention; Figure 2 is a perspective, partially sectional front view of a device according to the invention; Figure 3 is a front view of an enlarged portion of a liquid yeast metering device.

Like parts are numbered alike in the figures.

Figure 1 is a diagrammatic representation of a device 1 according to the invention, which comprises a liquid yeast metering device 2, a water metering device 3, and a mixing chamber 4. Liquid yeast metering device 2 is provided with a pipe 5, which is connected to a coupling 6 on a side remote from yeast metering device 2. Coupling 6 is preferably disposed as closely to liquid yeast metering device 2 as possible, so that pipe 5 will have a minimum length.

Furthermore connected to coupling 6 is a pipe 7, which is connected to water metering device 3, as well as a discharge pipe 8, which opens into mixing chamber 4 on a side 9 remote from coupling 6. Water metering device 3 comprises a cold water supply pipe 10 and a hot water supply pipe 11. In the situation as shown in Figure 1, a substance 12, for example flour, is present in mixing chamber 4. Substance 12 has been supplied to mixing chamber 4 via pipes (not shown).

The operation of the device 1 shown in Figure 1 is as follows. The liquid yeast present in yeast metering device 2 is metered and delivered to mixing chamber 4 via pipe 5, coupling 6 and discharge pipe 8. Residue of the yeast remains behind in pipe 8 thereby. After the first yeast has been supplied, a desired quantity of the water having a desired temperature, which temperature is effected by mixing the relatively cold water from pipe 10 with the relatively hot water from pipe 11, is supplied by water metering device 3 to mixing chamber 4 via pipe 7, coupling 6 and discharge pipe 8. The water will wash away all residue of the yeast which is present in coupling 6 and/or discharge pipe 8 and deliver it to mixing chamber 4 as yet. In this manner it is ensured that the desired quantity of yeast fluid is supplied to mixing chamber 4, whilst preventing residue of the yeast remaining behind in coupling 6 or discharge pipe 8.

Figure 2 is a perspective front view of a device according to the invention, which corresponds with the device which is diagrammatically shown in Figure 1.

Metering device 2 comprises two containers 13 for liquid yeast, which are each provided on the underside with an outlet opening 14. A coupling hose 15 is connected to each outlet opening 14, which coupling hose is connected with an end remote from opening 14 to an electromagnetically controlled valve 16. Valve 16 is connected on a side remote from coupling hose 14 to a pipe 17 which extends between the two valves 16. Between the two valves 16, pipe 17 is connected, via a coupling piece 18, to a hose 20 extending through a peristaltic pump 19. Hose 20 is connected with an end remote from pipe 17 to a flow meter 21, to the other side of which an electromagnetic valve 22 is connected. Valve 22 is furthermore connected to pipe 5, which is connected to coupling 6. Yeast metering device 2 furthermore comprises a cooling arrangement (not shown), by means of which the yeast containers 13 and the valves, the pump, the flow meter etc. are cooled to a temperature of preferably 4 °C. Yeast metering device 2 furthermore comprises insulation material 23, which surrounds the containers and the entire pump arrangement. Only pipe 5 extends partially through the insulation material 23 so as to be connected to coupling 6.

Metering device 4 comprises a mixing drum 24, which is rotated about a vertically extending axis of rotation by means of a motor 25. Mixing chamber 4 furthermore comprises two whisks 26, which are rotated in mixing chamber 24.

The device 1 which is shown in Figure 2 comprises a water metering device 3, in which cold and hot water being supplied via pipes 10,11 are mixed to a desired temperature and subsequently supplied in a desired quantity to pipe 7, which extends from water metering device 3 to coupling 6, which is disposed in yeast metering device 2. <BR> <BR> <BR> <BR> <P> Metering device 3 is furthermore provided with a control<BR> <BR> <BR> <BR> <BR> <BR> <BR> uni t 27 for control 1 i ng the del i very of yeast and water and for control 1 i ng the motors for rotating mixing drum 24 and whisks 26.

The operation of yeast metering device 2 will now be explained in more detail with reference to Figure 3, which shows an enlarged portion of yeast metering device 2. The control unit opens one valve 16 and closes the other valve, as a result of which liquid yeast

is carried from a yeast container 13 to pipe 17 via opening 14, coupling hose 15, and valve 16. Then the yeast is passed through flow meter 21 by means of peristaltic pump 19, and passed through valve 22 to pipe 5. The moment a desired quantity of yeast has been supplied to pipe 5 by means of the flow meter, valve 22 will be closed. When one container 13 becomes empty, the valve 16 associated with said container will be closed and the valve 16 of the other container 13 will be opened. Following that, the empty container 13 will be exchanged for a full one.

Via the relatively short pipe 5, which extends through insulation material 23 to coupling 6, practically all the yeast which is present outside the cooled portion of yeast metering device 2 is washed out of coupling 6 and discharge pipe 8 to mixing drum 24 by means of the water flowing through pipe 7.

When the device 1 is put out of operation for a prolonged period of time, the pump arrangement of yeast metering device 2 can simply be cleaned by connecting water hoses (not shown) to coupling hoses 15 instead of the yeast containers 13, by means of which water hoses all the yeast present in elements 15-22 is subsequently removed.

The invention has been explained with regard to the delivery of yeast and water to a mixing chamber 4. It will be understood, that also other substances, such as liquid bread improvers can be supplied to a mixing chamber in this manner, whereby fluid residue can be washed out of the discharge pipe by means of the water, and whereby both fluids are used in the mixing chamber.