Abstract: An improved and unique liquid light tube (guide) end cap assembly particularly useful in a system for the clinical analysis of liquid biological samples for directing wavelengths of light is described. The assembly comprises a light guide having projecting at one end portion thereof a quartz member and a housing for containing the end portion of the light guide and the quartz member, thereby forming an aperture between the quartz member and the housing, the aperture having a depth of between about 0.002 and 0.007 inches.

Abstract: For precision dispensing of fluids particularly for medical applications, a face valve has a valve member mounted for linear sliding movement across the face of a valve body, which has fluid passages therethrough, between positions in which respectively the valve member seals the ends of the fluid passages at the valve body face and a channel in the valve member connects the ends of the fluid passages. The valve body is of a hard corrosion resistant metal and the valve member is of bearing plastic material, both materials being inert to the fluids being dispensed. The valve is pressed against the face of the valve body by a spring which is oriented in a particular way to optimize valve life.