Gundelach Light Anode X-ray Tubes with Osmotic Regulation (1900-1905)

Gundelach X-ray Tube

The two bi-anode x-ray tubes featured here were manufactured by the Emil Gundelach company of Gehlberg, Germany. The larger of the two is shown above, while the smaller tube can be seen below.

Both employed Villard’s "osmosis" method of regulating the tube’s internal gas pressure. In fact, the Gundelach company was the very first to use this method for regulating an x-ray tube! More about osmo-regulation later.

As seen in the photos, the circular platinum target is positioned in the center of the tube’s spherical bulb and oriented at a 45 degree angle to the tube axis.

The cupped aluminum cathode in each tube is located at the point where the large glass arm is attached to the right side of the bulb (as seen in the images). The anode consists of a flat aluminum disk attached at the end of a rod that enters the bulb from the left side (as seen in the photo).

These tubes could have been used for either therapy or diagnosis (imaging).


The company logo, a scale hanging from the inside of a large "G," can be seen etched on the stem of the tube (image to right).

In addition to the company logo, the following is etched on the stem of the larger tube: "O. Carliczek, Chicago, D.R.P. No. 103100 Made in Germany."



Villard's osmo-regulation system involved heating a fine capillary that penetrated the tube wall in a flame until the capillary glowed red. At this temperature, atmospheric hydrogen gas would diffuse into the capillary and from there into the main body of the tube. This served as a periodic correction for the almost inevitable decrease of gas pressure inside the x-ray tube.

I believe that Gundelach frequently used a platinum-iridium alloy in the manufacture of the capillary.

The capillary would normally be protected by a glass tube (as seen in the photograph to the right). Of course, when the capillary was to be heated, the protective tube would be removed - carefully.

For more information about regulating gas pressure, click the "Info Button" on the directory page for X-ray and Gas Discharge Tubes. Or, just click here.

X-ray Tube Regulator

The Gundelach company was founded in 1852 by Emil Gundelach, a glass blower. Initially they offered a variety of Crookes and Geissler tubes. As a result, they were in excellent shape when the time came to begin manufacturing tubes specialized for x-ray production. In fact, they began doing so within a few month's of Rontgen's discovery. They continued producing x-ray tubes until the late 1920s.

Size: The smaller tube is approximately 10" long with 4.5" bulb diameter, and larger tube is approximately 13" long with 5.5" bulb diameter

The following image is from a James Biddle catalog published in 1904. It seems to be a close match for the tubes pictured above.

Gundelach Tube Biddle

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Last updated: 11/07/07
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