Abstract: A method for sealing the edges of a filter sheet (10) with wax to create a fluid-impermeable wax seal (11) enclosing a non-sealed portion (12). The method includes applying melted wax to the edges of the filter sheet, heating the treated filter sheet such that the wax permeates through the edges thereof, and then allowing the filter sheet to cool such that the wax congeals. The wax of the fluid-impermeable wax layer (11) has a durometer reading of about 75 to about 100 Shore A hardness at 25° C. and 85° C., a melt point of about 110° C. to about 180° C., a viscosity of less than about 100 cp at 155° C. and preferably includes ethylene bis stearamide. The wax layer increases the useful life of the filter sheet while providing a sheet which is easily released from a filter press and which retains integrity along the seal during repeated hot water sanitations.

Abstract: A filter sheet positioned between plates (14) of a filter press has a fluid-impermeable wax layer (11) sealing the sheet's perimeter. The wax preferably comprises ethylene bis stearamide and has a durometer reading of about 75 to about 100 Shore A hardness at 25.degree. C. and 85.degree. C., a melt point of about 110.degree. C. to about 180.degree. C., and a viscosity of less than about 100 cp at 155.degree. C. The wax layer increases the useful life of the filter sheet while providing a sheet which is easily released from a filter press and which retains integrity along the seal during repeated hot water sanitations.

Abstract: For simultaneously measuring the radioactivity of multiple samples arranged in a predetermined array of x rows and y columns, a fixed array of radiation counters arranged in the same array of x rows and y columns so that one of the counters is aligned with each of the multiple samples. Each of the counters has a pair of spaced electrodes; an electrical voltage source connected to the electrodes of all the counters for applying the same voltage across the electrodes of each of the radiation counters in the array; and sensing means connected to the electrodes of each of the radiation counters for independently detecting pulses of electrical current produced by ionization of the gas between the respective pairs of electrodes of each of the radiation counters. For measuring low-energy radiation, the radiation counters are windowless, a flow of ionizable gas is supplied to the counters, and the same flow rate of the ionizable gas is maintained through each of the radiation counters in the array.