1053 — Double-Anode Mercury Vapour and Gas-Filled Rectifying Valve

The 1053 is an industrial double-anode rectifying valve containing a mixture of mercury vapour and gas. Designed by Philips, this heavy-duty thermionic tube is engineered specifically for high-current low-voltage rectification applications, most notably in industrial welding rectifiers.

Overview

The 1053 is a specialized gas-discharge rectifier designed to deliver high currents under demanding industrial conditions. By utilizing a combination of mercury vapour and gas filling, the valve achieves a low internal voltage drop and high efficiency. It features a double-anode configuration within a single glass envelope, allowing for full-wave rectification or parallel anode operation. The primary documented application for the 1053 is in welding rectifiers, where a single valve is rated to supply a total rectified current of 25 A.

Mechanical Design and Physical Dimensions

The 1053 is constructed with a robust glass envelope designed to withstand high thermal and electrical loads. It is equipped with a specialized base and external connections to handle high currents safely.

• Mounting Position: The valve must be mounted strictly in a vertical position with the base pointing downwards. This orientation is critical to ensure the proper distribution of the liquid mercury and the correct condensation of mercury vapour during operation.
• Physical Dimensions:
  • Maximum overall height: 285 mm
  • Maximum bulb diameter: 101 mm
  • Maximum width across the anode terminals: 145 mm
  • Distance between the centers of the side anode terminals: 125 mm
• Weight: The net weight of the valve is 600 g, while its shipping weight is 2400 g.
• Electrode Connections: The filament connections are made via two pins (labeled 'f') at the bottom base. The two anodes (labeled 'a') are connected via separate terminals located on opposite sides of the glass bulb. A metal hook or handle is integrated at the top of the envelope to facilitate handling and support.

Filament and Preheating Requirements

The 1053 utilizes a directly heated, oxide-coated filament. Because it is a mercury-vapour tube, strict preheating protocols must be observed before applying anode voltage to prevent damage to the cathode from positive-ion bombardment.

• Heating Method: Direct heating by A.C.
• Filament Preheating Time ($t_f$): The recommended preheating time is 2 minutes. This delay allows the filament to reach its proper operating temperature and helps establish the correct mercury vapour pressure.
• Urgent Operation: Under urgent circumstances, the preheating time may be reduced to a minimum of 1 minute.
• Time Delay Control: To ensure the minimum preheating time is consistently met, the use of an external time delay switch (such as Philips type 4152) is recommended.
• Commissioning and Transport Delay ($T_w$): After transport, handling, or a prolonged interruption of service, a longer preheating period of 5 minutes is mandatory. This extended period ensures that any liquid mercury deposited on the electrodes or filament is completely vaporized and condensed in the lower portion of the tube before anode voltage is applied.

Electrical Specifications and Operating Limits

The electrical characteristics of the 1053 reflect its design as a low-voltage, high-current industrial rectifier. The gas and mercury vapour filling results in a highly stable voltage drop during conduction.

Typical Characteristics

• Arc Voltage Drop ($V_{arc}$): 9 V. This low voltage drop represents the potential difference across the tube during active conduction, contributing to high electrical efficiency.
• Ignition Voltage ($V_{ign}$): 16 V. This is the minimum voltage required to initiate the gas discharge and start conduction.

Limiting Values

• Transformer Voltage ($V_{tr}$): Maximum 48 $V_{\text{eff}}$, minimum 10 $V_{\text{eff}}$ (applicable under specified circuit conditions, designated as "Circuit a").
• Peak Inverse Anode Voltage ($V_{ainvp}$): Maximum 150 V. This is the maximum safe reverse voltage the tube can withstand during the non-conducting half-cycle.
• Average Anode Current ($I_a$): Maximum 12.5 A per anode.
• Peak Anode Current ($I_{ap}$): Maximum 75 A.
• Surge-Limiting Resistance ($R_t$): Minimum 0.25 $\Omega$.
• Mercury Temperature Range ($t_{Hg}$): 30 °C to 80 °C. The temperature of the condensed mercury must be maintained within this range during operation to ensure stable vapor pressure and prevent arc-back or starvation.

Current Capacity Calculation

The valve is rated for 25 A per valve in welding rectifier applications. This matches the electrical limits of the double-anode structure: with two independent anodes each rated for a maximum average current ($I_a$) of 12.5 A, the combined maximum average output current of the valve is: $\text{Total Current} = 2 \times 12.5\text{ A} = 25\text{ A}$

Technical Summary

The 1053 is a heavy-duty, double-anode, mercury vapour and gas-filled rectifying valve designed for low-voltage, high-current industrial applications. Featuring a directly heated oxide-coated filament, the tube requires a recommended preheating time of 2 minutes (reducible to 1 minute in urgent cases, and extended to 5 minutes after transport or long storage) to protect its cathode. With a typical arc drop of 9 V and an ignition voltage of 16 V, it operates efficiently under a maximum peak inverse voltage of 150 V. Each of its two anodes supports a maximum average current of 12.5 A (75 A peak), enabling a single valve to deliver up to 25 A in welding rectifier circuits. The tube must be operated vertically with the base down within a condensed mercury temperature range of 30 °C to 80 °C.