The Leeds & Northrop Model 8627 Optical Pyrometer is a high-quality measurement tool designed for industrial and business applications. This pyrometer features an integrated pistol-grip meter body for easy handling and precise measurements. With its origins in the United States, this product showcases the brand's reputation for producing reliable and accurate test equipment. The Leeds & Northrop Model 8627 is a trusted tool for those in need of precise temperature measurements in a variety of settings.
This listing is for the core measurement hardware, but is missing a critical operational component:
- What you have: You possess the main integrated pistol-grip meter body (which houses the analog readout scale, range selector switch, and adjustment knob) along with its original leather protective holster case.
- What is missing: The power source is missing. This specific handheld unit requires an internal battery (typically a specialized cylindrical cell or an adapted battery pack inside the handle compartment) to heat the internal filament. Without a working battery installed, the internal target filament will not light up, rendering the unit non-functional.
AI Mode Conversation: LEEDS & NORTHRUP MODEL 8627 OPTICAL PYROMETER
LEEDS & NORTHRUP MODEL 8627 OPTICAL PYROMETER
The Leeds & Northrup Model 8627 Optical Pyrometer is
a vintage, industrial-grade contactless thermal sensor designed to measure exceptionally high temperatures (such as flame, molten metal, or kiln environments) by matching the brightness of an internal filament to the target object. [
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The instrument relies on a two-part physical configuration: [
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- Main Body: A square, portable metal casing that houses the internal battery compartment, electrical circuit, and a master temperature display dial. The face features a prominent disk-shaped control knob to adjust current. [1]
- Handheld Eyepiece: A telescopic optical wand connected to the main body via a rugged, screw-on multi-conductor cable. When not in use, the eyepiece rests securely in a dedicated metal holster bracket mounted to the side of the housing. [1]
The device works on the disappearing filament principle: [
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- Targeting: The operator looks through the handheld eyepiece and aligns the optics so the internal incandescent lamp filament sits directly over the high-temperature light source (like a furnace interior or flame). [1, 2]
- Adjustment: Using the control dial on the main unit, the user alters the electrical current feeding the filament, changing its brightness. [1, 2]
- Matching: Once the current matches the heat intensity of the target, the filament "disappears" against the glowing background. [1]
- Readout: The accurate temperature is then read straight from the physical gauge dial located on top of the instrument box, typically calibrated in degrees Celsius or Fahrenheit. [1, 2]
Because it operates via direct human visual comparison, it offers a reliable mechanical alternative to modern digital infrared tools for high-temperature smelting and metalworking applications. However, it requires manual interaction and a human eye to successfully record a measurement. [
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Description & Technical Specifications
This device is a vintage, self-contained
disappearing-filament optical pyrometer used for non-contact high-temperature measurements in heavy industries like metallurgy, glass blowing, and furnace tracking. [
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- Manufacturer: Leeds & Northrup (L&N)
- Model: 8627 Optical Pyrometer
- Temperature Range: 1400°F to 3200°F (as clearly indicated by the dual scales on the display). [1]
- Scale Breakdown:
- Low Range (L): 1400°F to 2250°F (read on the bottom scale)
- High Range (H) / Maximum (M): Up to 3200°F (read on the top scale)
- Operation Mode: The user looks through the rear eyepiece lens at a glowing heat source, pulls the white trigger switch to power the unit, and turns the central °F control dial. This adjusts the brightness of a tiny internal wire filament until it perfectly blends into the background color of the heat source. Once it "disappears", the mechanical needle indicates the exact temperature on the scale. [1]