Gestra VK16 is a straight-through steam trap sight glass installed upstream of a steam trap. The product features a 1.0460 body and a MAXOS® borosilicate glass sight glass with mica protection. It supports a maximum working pressure of 40.0 barg and is available with DN15 to DN50 DIN flange connections. It is suitable for monitoring steam and condensate conditions in vertical or horizontal piping with pH ≤ 10, and can be used directly for on-site visual inspection in explosion-protected areas classified as Zones 0 to 22.
Product photo of Gestra VK16 steam trap sight glass, three-quarter view
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VK16 Straight-Through Sight Glass for Steam Traps | Gestra
Straight-through sight glass for steam traps with mica disc, for installation in horizontal or vertical pipelines.
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Specifications
- Connection type
- DIN flanges, PN 40
- Nominal size
- DN15, DN20, DN25, DN40, DN50
- Pressure-temperature rating
- 40.0 barg (20°C); 37.1 barg (100°C); 33.3 barg (200°C); 30.4 barg (250°C); 27.6 barg (300°C)
- Applicable media
- Steam and condensate, pH ≤ 10
- Body material
- 1.0460 (P250GH / C 22.8)
- Internal component material
- 1.0619 (GP240GH / GS C-25)
- Sight glass material
- MAXOS® borosilicate glass, DIN 7080
- Sight glass configuration
- With mica protection
- Design
- Straight-through, no moving parts
- Installation position
- Installed upstream of the steam trap
- Installation orientation
- Flow deflector facing downward; install according to the flow-direction arrow
- Piping installation
- Suitable for installation in vertical and horizontal piping
- PED compliance
- PED 97/23/EC, Group 2 fluids
- Suitability for explosion-protected environments
- Suitable for Ex areas in Zones 0, 1, 2, 20, 21, and 22; without Ex marking
Application scenarios
Monitoring steam and condensate conditions upstream of a steam trap
Installed upstream of a steam trap, the product enables observation of steam and condensate flow and conditions through the MAXOS borosilicate glass sight glass. It is suitable for PN40 applications and can be installed in vertical or horizontal piping.
Visual inspection of steam trap systems in explosion-protected areas
The product is suitable for Ex areas in Zones 0, 1, 2, 20, 21, and 22. It can be installed upstream of a steam trap for on-site visual inspection of steam and condensate conditions. The product is supplied without an Ex marking.
Installation & maintenance notes
Install in the specified orientation and upstream of the steam trap
During installation, ensure that the flow deflector faces downward and install the sight glass according to the flow-direction arrow on the body. The sight glass must be installed upstream of the steam trap and is suitable for vertical and horizontal piping.
Observe the applicable media and pressure-temperature ratings
Use only with steam and condensate. The medium pH must not exceed 10, and operation must remain within the applicable pressure and temperature ratings of the product.
FAQ
After installing the Gestra VK16 sight glass upstream of a steam trap, how can steam leakage or condensate accumulation be identified?
The VK16 uses sight glasses on both sides to observe the flow and condition of steam and condensate entering the steam trap. Under normal conditions, condensate flows beneath the flow deflector, which remains continuously immersed or at least in contact with the liquid surface, creating a siphoning effect that conveys the condensate to the steam trap. If the sight glass is completely filled with liquid, condensate accumulation is present. If the water level inside the sight glass decreases significantly during normal operation, the steam trap may be leaking live steam.
How should the pressure and temperature range of the Gestra VK16 be matched to steam system operating conditions?
The VK16 is rated PN40. For the DIN flange version, the maximum permissible pressure is 40.0 barg at 20°C, 37.1 barg at 100°C, 33.3 barg at 200°C, 30.4 barg at 250°C, and 27.6 barg at 300°C. During selection, verify the actual operating pressure, operating temperature, and medium pH. The applicable media are steam and condensate with pH ≤ 10.
How should the Gestra VK16 be installed, and can it be used in vertical piping?
The VK16 must be installed upstream of the steam trap and aligned with the flow-direction arrow on the body, with the internal flow deflector facing downward. This design is suitable for installation in both horizontal and vertical piping. Correct positioning of the flow deflector helps maintain condensate flow and siphoning beneath the deflector.
What nominal sizes and connection types are available for the Gestra VK16?
The VK16 is available in DN15, DN20, DN25, DN40, and DN50 sizes. DIN flange connections are rated PN40. Product documentation also lists ASME Class 150 RF and ASME Class 300 RF flanges, as well as threaded sockets and socket-weld ends for BSP and NPT threads. During procurement, match the product to the on-site pipe size, connection standard, operating pressure, and temperature.
Can the Gestra VK16 be used for on-site visual inspection in explosion-protected areas?
Yes. The VK16 does not contain an inherent potential ignition source and is outside the scope of ATEX Directive 94/9/EC. It can be used for visual inspection of steam and condensate conditions in Ex areas classified as Zones 0, 1, 2, 20, 21, and 22. The device is supplied without an Ex marking.