Abstract: A pressure balanced floating seal system positioned within a structure about a rotating shaft. The floating seal system has a cylindrical outer seal housing having a cylindrical internal recessed region formed in the outer seal housing with a retaining flange extending into said internal recessed region. A cylindrical inner seal housing is positioned within the internal recessed region. The inner seal housing has an annular internal surface for accommodating the rotating shaft. Two sealing member retaining grooves are formed in the inner seal housing annular internal surface and a lubricant recess is formed between the two grooves. An intermediate seal is retained on the forward side of the inner seal housing forward face between the inner seal housing and the outer seal housing at the retaining flange. Sealing members are positioned in the sealing member retaining grooves at substantially the same radius as the intermediate seal.

Abstract: A vibration isolation mount comprises a frame adapted for attachment to a pport member, a spring device mounted on the frame and adapted for attachment to a protected device, the spring device being movable on the frame to permit movement of the protected device relative to the support member, and a locking mechanism for limiting movement of the spring device on the frame, thereby to limit movement of the protected device relative to the support member.

Abstract: Apparatus for obtaining programmable threshold extension of an FM demodulator comprises a limiter preamplifier 4 and a variable gain buffer amplifier 6. The buffer amplifier 6 is provided with an external control node 16 such that the signal level fed from the buffer amplifier 6 to an injection locked oscillator/divider 8 can be programmed in dependence upon a control signal applied to the external control node 16. In this manner threshold extension of the FM demodulator can be selectively applied in dependence upon the noise level in an FM input signal to be demodulated. The limiter preamplifier 4 and the buffer amplifier 6 may form part of an automatic gain control circuit.