Description
Product Overview
Spirax Sarco Set of Windows and Gaskets (3, 4, 5) is a factory spare parts kit for single window and double window sight glasses. It restores fluid containment and visual inspection capability when existing sight glass windows suffer erosion, thinning from caustic alkali or hydrofluoric acid, or gasket wear downstream of steam traps.
Each renewal set comprises the toughened soda lime glass window (item 3) together with the upper top gasket (item 4) and lower bottom gasket (item 5). This renewal assembly permits field overhaul of worn optical observation ports without replacing the complete brass or bronze body housing.
Key Features
- Factory replacement kit matching original Spirax Sarco single and double window sight glass manufacturing specifications.
- Window discs manufactured from toughened soda lime glass compliant with BS 3463 standard.
- High-integrity sealing supplied by top and bottom gaskets fabricated from reinforced exfoliated graphite.
- Gaskets include thin stainless steel support rings to maintain pressure containment under operating thermal cycles.
- Supplied as a coordinated replacement grouping encompassing items 3, 4, and 5 for streamlined maintenance.
Technical Specifications
| Item / Parameter | Specification |
|---|---|
| Kit Designation | Set of windows and gaskets (Items 3, 4, 5) |
| Included Parts | Window (3), Top gasket (4), Bottom gasket (5) |
| Window Material (Item 3) | Toughened soda lime glass to BS 3463 |
| Top Gasket Material (Item 4) | Reinforced exfoliated graphite with stainless steel support ring |
| Bottom Gasket Material (Item 5) | Reinforced exfoliated graphite with stainless steel support ring |
| Host Body Design Rating | PN5 |
| Maximum Allowable Pressure (PMA) | 5 bar g @ 90 °C (72.5 psi g @ 194 °F) |
| Maximum Allowable Temperature (TMA) | 148 °C @ 3.5 bar g (298.4 °F @ 50.75 psi g) |
| Minimum Allowable Temperature | -29 °C (-20.2 °F) |
| Maximum Saturated Steam Operating Pressure (PMO) | 3.5 bar g (50.75 psi g) |
| Maximum Operating Temperature (TMO) | 148 °C @ 3.5 bar g (298.4 °F @ 50.75 psi g) |
| Minimum Operating Temperature | 0 °C (32 °F) |
| Cold Hydraulic Test Pressure | 7 bar g (101.5 psi g) |
| Steam Test Pressure (PTMX) | 3.5 bar g (50.75 psi g) |
| Bezel (Item 2) Tightening Torque | 60 N m to 65 N m (43 lbf ft to 47 lbf ft / 44 ft lbf to 48 ft lbf) |
Applications
- Routine maintenance and overhaul of Spirax Sarco single window sight glasses in sizes 1/2”, 3/4”, and 1” (including 3/8” variants).
- Renewal of clouded, scratched, or thinned glass ports on Spirax Sarco double window sight glasses in sizes 1/2”, 3/4”, 1”, 1-1/4”, 1-1/2”, and 2”.
- Installations downstream of steam traps and process equipment handling European Pressure Equipment Directive Group 2 fluids (steam, condensate, water, and compressed air).
- Preventive replacement in condensate return lines where chemical testing identifies caustic alkali or hydrofluoric acid attack on visual glass surfaces.
Replacement and Maintenance
- Isolate the sight glass by closing isolating valves, shutting the upstream stop valve first to prevent overpressurisation.
- Allow internal fluid pressure and temperature to normalize completely to ambient conditions before dismantling.
- Unscrew the threaded bezel (item 2) from the body.
- Remove the old upper gasket (item 4), glass window (item 3), and lower gasket (item 5). Note that gaskets contain thin stainless steel support rings; handle and dispose of them with care to avoid physical injury.
- Carefully clean the body seating recess and inspect internal surfaces for corrosion or debris.
- Fit the new window and gaskets, ensuring that a gasket (item 4) is correctly positioned on either side of each glass window (item 3).
- Thread the bezel (item 2) into the body and tighten to the specified torque of 60 N m to 65 N m (43 lbf ft to 47 lbf ft).
- Re-open isolation valves slowly to allow pressure and temperature to build up in a controlled manner, then inspect the bezel perimeter for leakage.
Ordering Instructions
Spares must be ordered using the description “Set of windows and gaskets” accompanied by the exact size and type of the host sight glass.
- Single window example: 1 off Set of windows and gaskets for a 1” Spirax Sarco single window sight glass.
- Double window example: 1 off Set of windows and gaskets for a 1” Spirax Sarco double window sight glass.