General features
The Alarm System WHISTLE –75 is a modern acoustic signalling system for Selective highpower Alarm for use aboard ship in order to:
 * Be instantly distinguished from other kinds of sound signals.
 * Be heard with a good margin above loud englne noise.
 * Function safely — even under hard operating conditions.

These are some of the requirements met by the WHISTLE series MKT 75/–. The material for all parts is chosen to withstand modern environmental demands as to corrosion, vibration, etc. In all WHISTLE units, the diaphragms — virtually unbreakable — are correctly fitted and therefore need no adjustment.

Contents of system
The Alarm System TYFON –75 comprises:

 * Fire Alarm — frequency 800 Hz.
   Coded or intermittent blasts, e.g. with a cycle of about 2 seconds, signal and silence periods being equal in length.

 * CO2 Alarm — frequencies 460–660 Hz
   Altering two-tone signal with 1 to 2 blasts per second.

 * Engine Alarm/Telephone Signal — frequency 400 Hz.

Single or recurrent blast with long intervals.

The choice of frequencies with great mutual differences and also the specially recommended time scheme have been preceded by practical tests in co–operation with auditory–medical experts. Since the signals are selective, even an unmusical person will understand what kind of alarm is sounding. For coding suggestions and arrangement, see last page.

Solenoid Valves are delivered for standard voltages 115–130, 230–240V AC and 12, 24, 115 and 230V DC. On all valves, a filter is fitted at the inlet side. For MKEV 75/460–660, the connection is pipe thread 1/2” and for the other types, pipe thread 1/4”.

Air consumption is approximately 4 to 5 litres per blast second. All signal units are normally choked for a working pressure up to 0,7 MPa overpressure.
Sound level, measured at a distance of 1 m, is over 130 dB, except for the engine alarm signal and telephone signal which, having a deep non–irritating tone, is on a level of about 120 dB.

Sordine may be applied to the resonance horn if the apparatus is located in a place where the sound intensity is annoying, for instance when WHISTLE KTV 75/400 is for the engine alarm or pump room telephone etc.

For explosive, corrosive or very hot areas, the solenoid valves can be removed and mounted separately, or alternatively be replaced by manual push button valves.

Frequency (basic): 400 Hz
Sound pressure level at 1 m (3’): 120–135 dB (Adjustable by means of screw)
Normal air consumption (free air): 2–5 l/s (0.07-0.18 cfs)
Valve type: TV 88
Working pressure (overpressure): 0,5–1,2 MPa (725-174 psi)
Valve orifice: Ø 8 mm (0.3”)

Power consumption
In–rush: 16 VA
Nominal: 8 VA

Weight: 1,5 kg (3.3 lbs)