PSK-75 air gun

The PSK-75 ([Efimov (1986)], Fig.12) is a configurable volume chamber (125, 250, 500 1000 ml) air gun with 75mm output port. The working pressure can range from 30 to 200 bar, while the air-gun can be deployed unpressurized. The solenoid electrovalves (Fig.13) are driven by 2 to 20 msec long pulses [Efimov and Kilikov (2001),Efimov (1998)] produced by the BUP-N sub-system 14. The power circuitry is set-up by thyristor devices and the seismic signature can be modified by different lenghts of the pulses.

The design of the towing system is such that its depth is maintained at 4-7 m with ship speeds ranging 8-12 kn, and it can be deployed at full speed by two-three men using winches or capstans.

figure

Figure 12: PSK-75 Air-gun (1000ml volume chamber) assembled with tow-system on deck.

figure

Figure 13: PSK-75 solenoids.

figure

Figure 14: BUP-N instrumental racks. Left (from top): monitor, digitizer SNSP2001/MC1, analog control. Right(from bottom): oscilloscope, solenoid control BUP-4, solenoid control BUP-5, second digitizer SNSP2001/MC-2.

figure

Figure 15: Air distribution panel..

Air delivery and control (fig.15) is such that one or two guns can work with different pressure settins.

To avoid the condensation freezing (survey in high latitudes), original connectors which maintain a constant diameter for air flow and heating of all the air system control were performed.