Kemlon Kemlon

Technical Information

Kemlon manufactures a wide variety of glass to metal seals for use as electriocal connectors.  The Kemlon glass sealed feedthrus are single pin seals designed to operate under pressure or vacuum.  The glass serves the dual purpose of bonding the pin and body heremetically as well as insulating them electrically.  Only high quality, high insulation glasses are used on Kemlon feedthrus for low dielectric loss.  In some cases high alimina ceramic is used to reinforce the glass.  It also serves as an extention of the insulation for designs that require longer body shells or arc paths.  Both the design and the manufacturnig techniques of using ceramic to reinforce glass in high pressure electrical connectors are patented Kemlon processes.


The standard construction of Kemlon glass sealed feedthrus is 300 series stainless steel bodies, high temperature glass, and 52% nickel alloy pin.  Other materials are available upon request.  A represenative list of materials in which seals are available is shown in Table 1.

Body or Shell Pin Contact
303 or 304 S.S. 52% Nickel Alloy
316 S.S Kovar
Hast C Molybdenum
Inconel 446 S.S.
Titanium Tantalum
Kovar Hast C
Carbon Steel Tantalum

Current Capacity

The standard carrying capacity of Kemlon glass sealed feedthrus is a function of three conditions.

  1. The diameter of the pin
  2. The pin material type
  3. The operating temperature

In a glass seal the current passing through the pin causes some resistive heating.  Glass seals are not easily damaged by this heating doe to the high temperature proprities of the glass.  Therefore, the current carrying capacity depends upon how much "warming" is acceptable.  Kemlon has set its current capacities for a maximum of 50 deg F temperature rise.

Current Capacities of Standard Kemlon Glass Seals (52 alloy) in Amperes with 50 Degree Temperature Rise
Pin Diameter Service Temperature
Inches mm 25 °C / 77 °F 175 °C / 374 °F
0.030 .076 3.8 2.6
0.040 1.02 5.9 4.1
0.062 1.57 10.0 6.9
0.093 2.36 16.6 11.5
0.125 3.18 24.5 17.0
0.187 4.75 40.5 28.0

In nonstandard materials of construction are used, then a multiplier should be applied to these current capacities shown in Table 2.  At 78 deg F the specific resistivity of various materials is shown in Table 3.  The multiplier is simply the square of the ratio of the specific resistivity of the 52% Nickel alloy to the specific resistivity of the pin material chosen.

Specific Resistivity of glass sealing alloys at 78 deg F
Material Ohms per Circular Mil Foot Micro Ohm Centimeter Current Multiplier
52% Nickel Alloy 260 43.0 1.0
Kovar/Rodar 294 48.0 0.9
446 S.S. 402 66.8 0.8
Tantulum 81 13.5 1.8
Molybdenum 34 5.7 2.8
Inconel X-750 731 121.0 0.6

Pin Arrangement

Standard on all Kemlon seals is straight pin arrangement.  Hovever, eyelets and tubular ends are available on request.  Each eyelet lengthenes the pin .015 inch.

Pin termination


All Kemlon glass sealed feedthrus have tin plated conductors for ease of soldering.  Gold plating is also available if required by special request.

Helium Leakage

Kemlon seals are designed to meet or exceed Helium leak test of 0.00000001 cc/sec.  Represenative samples are inspected using a mass spectrometer leak detector to insure product integrity.  In extreme circumstances 100% batch inspection can be preformed for an additional charge.