Sight Glass Technical Support — Selection, CAD Drawings & Installation
From choosing the right glass to replacing a broken window — technical support from the engineers who build SIGHTSPEC sight glasses.
What Our Technical Support Covers
Four support areas cover the full life of a sight glass — before you order, at installation and long after delivery. All support is provided by factory engineers, in English, with answers within 24 hours on working days.
Selection Assistance
We match glass type, size, connection, pressure and temperature to your process — for new builds and for replacing windows in existing vessels and piping.
CAD Drawings
Dimensional drawings in DWG and PDF before you order, so your designers can verify fit, flange drilling and envelope without guesswork.
Installation Guidance
Gasket selection, torque values, clamp alignment and heating options — the details that stop leaks, glass stress and premature failures.
After-Sales Service
Glass breakage replacement, gasket kits and spare parts, with a warranty process handled directly by the factory.
Selection Assistance — Five Questions We Ask
Answer these five questions and the right sight glass — or a custom configuration — becomes obvious. Send the answers with a photo or drawing and we confirm the model within 24 hours.
| Question | What We Need to Know |
|---|---|
| What is the opening size? | Measure the clear opening or existing window envelope. Standard tri-clamp sizes run 1/2"–12" (DN15–DN300), threaded 1/4"–3", flanged 2"–8". |
| Which connection? | Tri-clamp for sanitary lines, NPT/BSP threaded for compact high-pressure service, ANSI/DIN flanged for large process windows. Weld-in and bolt-on are available. |
| Pressure and temperature? | Borosilicate to DIN 7080 handles up to 572°F (300°C); threaded models are rated up to 100 bar. Vacuum service uses the FV rating (to 230 psi on tri-clamp models). |
| What media is inside? | Aggressive chemicals favor borosilicate or quartz with matching gaskets (PTFE, FKM, EPDM); food and pharma lines need USP Class VI compliant materials and hygienic finishes. |
| New build or retrofit? | For retrofits we match existing bolt patterns and glass dimensions exactly — send a photo or drawing and we confirm compatibility before you order. |
Product families and full ratings: tri-clamp sight glasses, sight flow indicators, threaded sight glasses and flanged sight glasses.
CAD Drawings Before You Order
Every SIGHTSPEC window can be supplied with a dimensional drawing before production. For retrofit windows we work from your measurements to guarantee the envelope fits.
- DWG and PDF drawings for approval — including custom flange drilling and bolt patterns.
- Drawings returned within 24–48 hours for standard sizes, slightly longer for complex OEM designs.
- Full OEM drawing and sampling support on our OEM / ODM page.
Installation Guide
Most sight glass field failures trace back to installation: old gaskets, uneven torque or thermal shock. Follow these four steps and the window will seat correctly first time.
Inspect on Arrival
Unpack and check glass and gaskets for transport damage. Report any cracked glass or damaged seals within 7 days with photos for a free replacement.
Fit New Gaskets
Always install new gaskets when replacing a window. Match the gasket to your media — EPDM for water and mild chemicals, FKM for oils and solvents, PTFE for aggressive media.
Align & Torque Evenly
Center the glass in the opening and tighten clamps or bolts in a criss-cross pattern, in stages, to the recommended torque — uneven clamping is the most common cause of glass cracking.
Pressure Test & Operate
After installation, gradually bring the line to operating pressure and check for leaks. Thermal shock is the main enemy: avoid cold liquid hitting a hot glass surface.
Gasket Selection Table
Gaskets are the sealing heart of every sight glass installation. Match the gasket to your media and temperature — wrong gasket selection is a leading cause of leaks. For chemical, oil and gas duty, review the chemical processing and oil & gas application guides.
| Media | Recommended Gasket | Temperature Range |
|---|---|---|
| Water, steam (low), CIP chemicals | EPDM | –40°F to 300°F |
| Oils, fuels, solvents, moderate acids | FKM (Viton) | –20°F to 400°F |
| Strong acids, aggressive chemicals | PTFE | –100°F to 500°F |
| Pharma, food, beverage (USP Class VI) | Silicone / hygienic TPE | –60°F to 400°F |
After-Sales: Glass Breakage & Gasket Replacement
Sight glass windows are service parts by nature — glass is a consumable that can be damaged by thermal shock, overpressure or impact. Our after-sales service keeps your line running with fast replacement supply. For pharma and food lines, see our pharmaceutical and food & beverage application pages.
🪟 Glass Breakage Replacement
Send photos of the failed window and the size or nameplate. We supply a drop-in replacement — glass, gaskets and clamps — matching your existing envelope, with express shipping options for downtime-critical lines. Manufacturing defects found on arrival are covered by warranty.
🧩 Gasket & Spare Kits
Order spare gasket kits with every window so maintenance crews can reseal during planned stops. Kits include gaskets, washers and a torque specification card for your exact model — EPDM, FKM, PTFE, silicone or hygienic TPE.
Common Sight Glass Issues
A quick diagnostic table for the field. If your symptom is not listed, send photos and a description — we diagnose the root cause and recommend the fix.
| Symptom | Likely Cause | Fix |
|---|---|---|
| Glass fogs or clouds internally | Moisture ingress or long-term thermal stress | Replace the glass; consider an anti-fog heating option for humid duty |
| Leak at the gasket face | Worn gasket, uneven torque or damaged sealing surface | Replace gaskets and re-torque in sequence to the specified value |
| Glass cracked or shattered | Thermal shock, overpressure, impact or uneven clamping | Replace with the correct glass type; verify pressure rating and clamp alignment |
| Flow indicator not spinning | Rotor stuck on deposits or worn parts | Disassemble, clean and check the rotor; replace parts from our spare kits |
Technical Support FAQ
How fast do you answer technical questions?
Do you provide CAD drawings before purchase?
What if the glass breaks in service?
Can you replace a sight glass on an existing vessel?
Which gasket should I use for my media?
Do you support installation on site?
Need Help Spec'ing a Sight Glass?
Send your size, connection, pressure and media — our engineers reply within 24 hours with a model recommendation and drawing.