Ptfe-lined Sight Glass Material Selection And Installation Application

A PTFE lined sight glass combines a corrosion-resistant PTFE liner with a toughened borosilicate glass viewing tube. The liner shields the metallic housing from acid attack. The glass withstands thermal shock. For PTFE lined pipe systems, this component serves as an inspection point. Select flanged connections (PN10, PN16, or 150LBS) and confirm temperature rating (-29°C to 200°C). Specify spark-tested PTFE lining (min 3mm) for permeation resistance.

Glass Material: Toughened Borosilicate

Borosilicate glass is the standard for sight glass windows. Its low thermal expansion coefficient provides resistance to thermal shock. The glass withstands sudden temperature fluctuations common during CIP cycles. Oil-tempering and quenching per BS 3463 ensure impact resistance.

Glass properties for PTFE lined piping systems:

• High light transmission for clear observation

• Low thermal expansion coefficient

• Chemical corrosion resistance from acid fumes

• Pressure rating up to 10 kg/cm²

PTFE Liner Integration and Corrosion Protection

The PTFE lining isolates the metallic body from corrosive media. Minimum 3mm thickness ensures permeation resistance against HCl, H₂SO₄, and hot NaOH. The liner is molded and mechanically locked into the body, preventing blowout under vacuum or pressure surges.

Liner design features:

• Virgin PTFE lining per ASTM D1457

• Minimum lining thickness: 3mm (exceeds ASTM F-1545)

• High-voltage spark testing (10-15 KV) for porosity-free liner

• Vent holes to release trapped gases

Temperature and Pressure Ratings

The PTFE lined pipework assembly is rated for -29°C to 200°C continuous service. Flanged connections are available in PN10, PN16, and 150LBS ratings. The assembly handles full vacuum service with hydrostatic testing at 10 kg/cm².

Design Configurations for Process Visibility

PTFE lined sight glasses are available in tubular full-view and double-window types. The tubular design provides 360-degree visibility. The double-window design allows observation from two sides for pipelines with limited access.

Standard sizes for PTFE lined pipes & fittings:

• 1/2" to 12" (15mm to 300mm) nominal bore

• Flanged ends per ANSI B16.5 Class 150, DIN, or BS standards

• Customizable face-to-face dimensions

Applications and Installation

PTFE lined sight glasses are specified for chemical processing, pharmaceutical manufacturing, petrochemical refineries, and water treatment. The PTFE lined pipework design ensures compatibility with concentrated mineral acids, chlorinated solvents, and reactive chemicals.

Installation and specification checks:

1. Verify PTFE liner matches media compatibility

2. Confirm borosilicate glass for thermal shock resistance

3. Specify flange rating (PN10, PN16, or 150LBS)

4. Select tubular or double-window configuration

5. Request spark test certification for liner integrity

6. Confirm -29°C to 200°C temperature rating

The PTFE lined sight glass provides safe visual monitoring for corrosive process lines. PTFE lined pipe price varies with size and pressure rating. PTFE lined pipes & fittings are available in standard configurations. PTFE lined pipework systems incorporate sight glasses as inspection points. PTFE lined piping systems benefit from visual verification capability.

FVF PTFE Lined Sight Glass

• FVF lined sight glass provides reliable and safe visual indication of fluid flow on any corrosive service. Safe and shatter-proof,each window consists of two glasses,cemented together by a proprietary adhesive.
• Fluid flow can be viewed from either top or bottom.No product retention when it is installed vertically.
• It is widely used in corrosive services in chemical and petrochemical plants, pharmaceutical plants and food and beverage processing. 

Product Parameter

Materials of Main Parts

Technical Specification