Conax Technologies

Company Overview

Conax Technologies, headquartered in Buffalo, New York, has been designing and manufacturing compression seal fittings and temperature sensors for over 60 years. The company has established itself as the industry standard for packing gland fittings used in sample probe assemblies, thermocouple installations, and other instrumentation penetrations into pressurized process systems. Their products are found in virtually every sector of the process industries — oil and gas, chemical processing, power generation, aerospace, semiconductor manufacturing, and nuclear energy.

What distinguishes Conax from generic compression fitting manufacturers is their singular focus on the compression seal principle and the breadth of their sealant and material options. While many instrumentation fittings rely on ferrule-based compression (such as Swagelok-type fittings), Conax packing glands use a fundamentally different sealing mechanism that offers distinct advantages for probe assembly applications.

The PG Packing Gland Product Line

The Conax PG series is the core product line used in sample probe assembly fabrication. These packing glands provide a pressure-tight, adjustable seal around a probe tube (or thermocouple sheath) that allows the tube to be inserted, retracted, or repositioned without breaking the pressure boundary.

How the Compression Seal Works

The PG packing gland consists of a machined body with a bore, a sealant element placed around the probe tube inside the bore, and a gland nut (follower) that threads onto the body. As the gland nut is tightened, it compresses the sealant element axially, causing it to expand radially against both the probe tube outer diameter and the packing gland bore inner diameter. This creates a pressure-tight seal on both surfaces simultaneously.

This design provides several key advantages for sample probe assemblies:

• Adjustability — the probe tube can be repositioned (inserted deeper or withdrawn) by loosening the gland nut, adjusting the probe, and retightening
• Reusability — sealant elements can be replaced in the field without removing the packing gland body from the process connection
• Multi-element sealing — multiple sealant elements can be stacked for higher pressure ratings or redundant sealing
• Accommodates tube run-out — the compliant sealant element compensates for minor variations in probe tube OD or straightness

PG Series Size Range

Conax PG packing glands are available in a range of sizes designated PG2 through PG9, corresponding to the packing gland bore diameter and the range of probe tube ODs each size accommodates:

The most commonly specified sizes for sample probe assemblies are the PG4 and PG5, which accommodate the 1/4" and 3/8" OD probe tubes that represent the vast majority of gas and liquid sampling installations.

Sealant Options

One of Conax's primary advantages is the range of sealant materials available for their PG packing glands. The sealant must be compatible with both the process fluid and the operating temperature. Standard options include:

• TFE (PTFE/Teflon) — the most common sealant for general-purpose service from cryogenic temperatures to approximately 500 degrees F; chemically inert to virtually all process fluids
• Lava (calcium silicate) — for high-temperature applications up to 1,600 degrees F where PTFE would degrade; commonly used in furnace and reactor penetrations
• Silver — for extreme-temperature and high-purity applications; provides a metal-to-metal seal path
• Graphite — for high-temperature service in reducing atmospheres; resistant to radiation (nuclear applications)
• Vespel (polyimide) — for high-temperature service up to approximately 900 degrees F with better mechanical properties than PTFE
• Buna-N, Viton, and silicone elastomers — for specific chemical compatibility requirements

Material Options

Conax manufactures PG packing gland bodies and gland nuts in a wide range of alloys to match the process environment:

• 303 and 316 stainless steel — standard for most industrial applications
• Monel 400 and K-500 — for HF acid, sour gas, and marine environments
• Hastelloy C-276 — for aggressive chloride and mixed-acid service
• Inconel 600 — for high-temperature and nuclear applications
• Carbon steel — for non-corrosive, low-cost installations
• Brass — for low-pressure, non-corrosive utility applications

Why Conax Is the Industry Standard

Conax PG packing glands have become the de facto standard for sample probe assembly fittings because they address the specific needs of the application better than alternative fitting types. Unlike ferrule-based compression fittings, which permanently swage onto the tube and fix its position, Conax packing glands allow the probe tube to be adjusted, removed, and reinstalled. Unlike threaded pipe connections, packing glands provide a seal around a smooth tube without requiring threads that create dead volume and crevice corrosion sites.

The combination of adjustability, broad material and sealant selection, pressure ratings suitable for most process applications, and a six-decade track record of reliable performance makes Conax the first choice for probe assembly fabricators and end users alike.

SampleProbeAssembly.com — Authorized Distributor and Fabricator

SampleProbeAssembly.com is an authorized distributor of Conax Technologies products and a qualified fabricator of complete sample probe assemblies using Conax PG packing glands. We maintain inventory of the most commonly specified PG sizes and materials, and we build finished probe assemblies to customer specifications — combining Conax packing glands with probe tubes, process connections, isolation valves, and any required coatings or special materials.

By sourcing Conax components directly and fabricating assemblies in-house, we deliver complete, ready-to-install sample probe assemblies with full material traceability and documentation — without the lead time and markup associated with ordering individual components from multiple suppliers.