Abstract: In a purge gas system for a lithographic apparatus, a rate of flow of purge gas to the system is reduced substantially once a contamination level has fallen below a threshold level. The control may be on the basis of a detected level of contamination or on the basis of a timetable.

Abstract: In a purge gas system for a lithographic apparatus, a rate of flow of purge gas to the system is reduced substantially once a contamination level has fallen below a threshold level. The control may be on the basis of a detected level of contamination or on the basis of a timetable.

Abstract: A method is described for injection-moulding a product by means of the so-called gas-injection method. A special feature of the method is that in addition to the injection of gas into the product cavity (10) via a first gas inlet (51), gas is injected into a spill cavity (20) via a second gas inlet (52). The amount of material (1) flowing from and toward the spill cavity (20) can be controlled by the location of the second gas inlet (52). Moreover, a variant of the method prevents the formation of so-called dead ends. By means of another variant of the method in accordance with the invention it is possible to prevent the occurrence of so-called flow lines.

Abstract: A height-adjustable table for supporting a patient during medical examination or treatment in which a patient support table top mounted on a carrier 2 is connected to a base 3 by a parallelism maintaining linkage comprising a diamond or rhombus shaped linked assembly of four mutually pivoted equal struts 6, 7, 8, 9, pivotally attached top and bottom to the carrier 2 and to the base 3, and intermediately to the centers of first and second struts 17, 18 which are attached at their ends for free rectilinear displacement, to slides 20, 22, 24, 26, mounted on the carrier 2 and the base 3. Inextensible diagonal links 30, 32 connect diagonally opposed slides 24, 22 and 20, 26, to form an assembly of good horizontal and vertical stiffness even at the maximum height adjustment which is effected by e.g. a screw jack 5.