Abstract: The invention relates to a drainage pipe with perforations for draining whey from a whey/curd mass, in which the perforations are formed by small holes, and the hole size lies within the range 0.05-3 mm, while the hole density lies within the range 5-50,000 holes/cm.sup.2. Such a pipe is used in the preparation of cheese. In a drainage pipe which is provided with a large number of small holes, a larger part of the surface can be perforated, with the result that the drainage is more efficient. A natural counterpressure can be built up by varying the hole size and the hole density over the surface of the pipe, thus making expensive facilities for regulating the counterpressure unnecessary. The hole size and/or hole density can be varied in such a way over the surface of the pipe that the open surface increases from top to bottom. Various grid patterns are described for this.

Abstract: The invention relates to a sealing element for forming a liquid-tight seal between two tubular elements running essentially parallel. The sealing element consists of positioning means which are in the form of a flange which is fixed to the inner element of the tubular elements and which is provided on its periphery with a groove which accommodates, in a slightly wedged fit, an endless element of flexible material sealing the groove. On the inside of the groove one or more supply apertures for a compressed medium are present. When the compressed medium is supplied, the endless element of flexible material is moved outwards against the outer element of the tubular elements, in order to form a liquid-tight seal between the two columns. The element can be manufactured simply and cheaply from commercially available materials. The element is also easy to remove from the positioning means and replace. If water is used as the compressed medium, in the event of leakage's, no damage is caused to the products.