1173 — Single-Anode Mercury-Vapour and Gas-Filled Rectifying Valve

An industrial-grade, single-anode rectifying valve designed for high-current power conversion, battery charging, and industrial power supplies.

Overview

The 1173 is a directly heated, single-anode, mercury-vapour and gas-filled rectifying valve. It is specifically designed for industrial rectifier applications, where it can deliver up to 4 A of average current per valve. A typical application includes charging or buffering lead-acid battery banks up to a maximum of 110 Pb-cells. To ensure reliable starting and stable operation under varying load conditions, the valve incorporates an auxiliary ignition electrode.

Construction and Physical Specifications

The 1173 is built with a heavy-duty glass envelope designed to withstand the thermal and mechanical demands of industrial environments.

• Anode Connection: The anode is terminated at the top of the bulb via a robust M6 screw connector (labeled 'a').
• Base and Socket: The tube features a special 3-pin base (Spec. 3p) with three pins of 4 mm diameter. It is designed to be installed in a type 1287 socket.
• Mounting Position: The valve must be mounted vertically with the base down to ensure proper distribution of the liquid mercury.
• Physical Dimensions: The maximum overall height of the tube is 189 mm, and the maximum bulb diameter is 62 mm.
• Weight: The net weight of the valve is 165 g, while the shipping weight is 390 g.

Filament and Pre-Heating Requirements

The 1173 utilizes a directly heated, oxide-coated filament. Because it is a mercury-vapour tube, strict pre-heating protocols must be followed to vaporize the mercury before applying anode voltage, preventing damage to the cathode coating.

• Filament Voltage ($V_f$): 1.9 V
• Filament Current ($I_f$): 13 A
• Calculated Filament Power: $1.9\text{ V} \times 13\text{ A} = 24.7\text{ W}$ (calculated from the nominal filament voltage and current)
• Heating Supply: Direct by A.C.
• Pre-heating Time ($T_w$):
  • The standard recommended pre-heating time is 1 minute.
  • Under urgent circumstances, this pre-heating time may be reduced to a minimum of 45 seconds. A type 4152 time-delay switch can be used to automate this delay.
  • Following transport or after a long interruption of service, the pre-heating time ($T_w$) must be extended to 5 minutes to ensure complete redistribution of the mercury.

Ignition and Auxiliary Electrode Operation

The 1173 exhibits a typical arc voltage ($V_{arc}$) of 12 V and a typical ignition voltage ($V_{ign}$) of 22 V.

To reliably achieve the low ignition voltage of 22 V, an auxiliary D.C. supply unit delivering a minimum of 40 V and a current of at least 10 mA must be connected. This auxiliary supply is connected via a current-limiting resistor between the auxiliary ignition electrode ah (positive potential, +) and the cathode (negative potential, -). The use of a Philips Auxiliary Ignition Unit type 1289 is recommended for this purpose.

Operating Characteristics

The 1173 can be operated in several rectifier circuit configurations. The operating characteristics for these configurations (designated a through g) are detailed below, specifying the transformer secondary voltage ($V_{tr}$ in $V_{eff}$), the direct output voltage ($V_o$), and the direct output current ($I_o$):

Limiting Values and Absolute Maxima

The valve's absolute maximum ratings are divided into two distinct operating regimes, depending on the maximum peak inverse voltage and the thermal environment:

To protect the tube from damage during transient overcurrent conditions, a minimum surge-limiting resistance ($R_t$) of 0.75 $\Omega$ must be maintained in the anode circuit.

Technical Summary

The 1173 is a specialized, single-anode, mercury-vapour and gas-filled rectifying valve designed for demanding industrial power applications. Featuring a high-current 1.9 V, 13 A directly heated filament, the tube is capable of delivering up to 4 A of average anode current and charging battery systems up to 110 Pb-cells. It utilizes a top-cap M6 anode terminal, a special 3-pin base, and must be operated in a vertical, base-down position. By employing an auxiliary ignition electrode connected to a suitable D.C. supply, the valve achieves a low ignition voltage of 22 V and a stable arc voltage of 12 V. Depending on the thermal conditions and circuit configuration, the 1173 supports peak inverse voltages up to 850 V, providing a robust solution for industrial rectification.