1037 — Double-Anode Mercury-Vapour and Gas-Filled Rectifying Valve

The 1037 is an industrial double-anode rectifying valve designed for high-efficiency power rectification. Utilizing a combination of mercury vapour and gas filling, this valve is engineered to deliver high currents with a low internal voltage drop. Its primary application is in heavy-duty battery charging systems.

Technical Specifications and Filament Heating

The 1037 features a directly heated, oxide-coated filament designed to operate from an alternating current (A.C.) supply. Because the valve contains mercury vapour, specific preheating protocols must be strictly followed to ensure the mercury is fully vaporized before anode voltage is applied. This prevents damage to the cathode coating from ion bombardment.

For automated system integration, a time delay switch (such as type 4152) can be utilized to enforce the necessary preheating period. Following transport or any prolonged period of non-operation, the preheating time must be extended to 5 minutes to ensure proper mercury distribution within the envelope.

Mechanical Construction and Mounting

The physical design of the 1037 is optimized for high-current industrial service, featuring robust external connections and a specialized base to handle high filament currents.

• Base Type: Goliath base.
• Associated Socket: Type 65909 BG/01.
• Mounting Position: Vertical, base down only.
• Anode Connections: Two separate anodes ($a$ and $a'$) terminate in M4 screw connectors on the side of the glass envelope, positioned at a $60^\circ$ angle relative to each other.
• Physical Dimensions:
  • Maximum overall height: 240 mm
  • Seated bulb height (above base): 193 mm
  • Maximum bulb diameter: 85 mm
  • Maximum base diameter: 50 mm
• Weight: Net weight of the valve is 290 g. For shipping, a standard package of 6 valves has a gross weight of 3600 g.

Electrical Characteristics and Operating Limits

The electrical performance of the 1037 is characterized by a low internal voltage drop (arc voltage) once ignition occurs, which is typical of mercury-vapour and gas-filled rectifiers.

Typical Characteristics

• Arc Voltage ($V_{arc}$): 9 V
• Ignition Voltage ($V_{ign}$): 16 V

Limiting Values (Absolute Maxima)

To ensure reliable operation and prevent arc-back or cathode degradation, the circuit parameters must be kept within the following limits:

• Transformer Voltage ($V_{tr}$): Maximum $60\text{ V}_{eff}$, Minimum $15\text{ V}_{eff}$
• Anode Inverse Peak Voltage ($V_{ainv_p}$): Maximum 185 V
• Anode Current ($I_a$): Maximum 3 A
• Anode Peak Current ($I_{ap}$): Maximum 18 A
• Series Resistance ($R_t$): Minimum $1.75\ \Omega$
• Operating Temperature Range ($t_{Hg}$): $30^\circ\text{C}$ to $80^\circ\text{C}$ (condensed mercury temperature)

The minimum series resistance ($R_t$) of $1.75\ \Omega$ is a critical safety parameter required to limit peak inrush currents and protect the cathode from degradation during start-up or transient conditions.

Applications and Circuit Integration

The primary application of the 1037 is in industrial battery chargers. A single valve is rated to deliver a charging current of up to 6 A and can support charging configurations of up to 20 lead-acid (Pb) cells connected in series.

In practical installations, the double-anode configuration allows for full-wave rectification using a single valve. The circuit must be designed to maintain the condensed mercury temperature ($t_{Hg}$) within the specified $30^\circ\text{C}$ to $80^\circ\text{C}$ range, as temperatures outside this window can lead to either failure to ignite (too cold) or premature arc-back (too hot).