FIVE MAIN COMPONENTS TO ALL FLAT GLASS GAUGES
- Chamber: Center of the gauge, and is the part that primarily contains the process fluid. It is machined from bar stock. The gasket seat is recessed for lateral support, and easy positioning.
- Glass: Provides the visual interface between the process fluid and the outside.
- Cover: Protects the glass, and provides the compression surface for sealing the gauge. The cushion seat is surfaced for lateral support and easy positioning.
- Gasket/Cushion: Provides for a seal between the chamber and glass (gasket), and protects the glass from mechanical stresses from the cover (cushion). For a given gauge, the gasket and cushion are normally the same material.
- Bolts/Studs/Nuts: Provides a uniform compression load to the gauge for pressure sealing.
REFLEX STYLE LEVEL GAUGE
Reflex gauges have a single piece of glass, mounted on one side of the chamber. This piece of glass is flat on the outside, and has a series of prisms on the inside, facing the process fluid. When light strikes the portion of the glass covered by a liquid, the light is reflected from the back of the chamber. This area appears “black”. When light strikes the glass where no liquid is present, the prisms reflect the light directly out of the gauge. This area appears “silvery”. Reflex gauges provide an excellent way to measure clear, or difficult to see fluids. The “silvery”/”black” interface is easy to see from several feet away.
WHY USE FLAT GLASS GAUGES
Flat Glass Gauges have been in use for over 100 years. They give you the ability to directly view the process fluid under temperature/pressure conditions that would render most other level technologies useless. Their construction is very robust, and reliable. They define the term “simple to use”. After installation, the only tool you will need is your eyes. Flat Glass Gauges are relatively inexpensive as compared to most other level technologies.
Other Features
- They do not need electrical power to operate. This can be a great advantage in the case of a power outage.
- Simple to install – no calibration is necessary.
- Can be used as a reference to check, or calibrate, other level technologies.
- Pressure rating from vacuum to 4000psig.
- Temperature rating from -425oF to 750oF
- Not affected by the chemical or electrical properties of the process liquid. Specific gravity, dielectric, conductivity, surface turbulence, vapor, foam, etc. no longer needs to be considered.
FLAT GLASS GAUGES VS. TUBULAR GLASS GAUGES
KENCO offers a wide range of Flat Glass Gauges and Tubular Gauges. With all of those choices, one of the basic questions is, “Should I use Flat Glass or Tubular Glass gauges?”
The answer is fairly simple. If the process pressure is under 500psig and the process temperature is under 400
oF, tubular style gauges should be considered. KENCO tubular gauges shield the glass on all four sides to virtually eliminate glass breakage, and tubular gauges are even more cost effective than flat glass gauges. Regardless of the style chosen, KENCO’s high quality gauges will provide you with many years of reliable service.
MEDIUM PRESSURE FLAT GLASS GAUGES
KENCO Medium Pressure Flat Glass Gauges are versatile enough for most common process conditions. Standard carbon steel gauges meet the requirements of NACE MR0175. Unlike other manufacturers, there is not additional charge for NACE. All materials meet or exceed ASTM specifications. Model KMR Reflex Gauges can reach process pressures up to 3000psig. Model KMT Transparent Gauges can handle pressures up to 2000psig. While these gauges are not specifically designed for steam service, the Model KMR gauges will perform at saturated steam pressures up to 300WSP. The Model KMT will perform at saturated steam pressures up to 600WSP, depending upon gauge size. Mica shields are recommended for Model KMT when used in steam. Shields cannot be used with Reflex Gauges.
HIGHT PRESSURE FLAT GLASS GAUGES
KENCO High Pressure Flat Glass Gauges have a superior rugged design for the most demanding process conditions. Standard carbon steel gauges meet the requirements of NACE MR0175. Unlike other manufacturers, there is no additional charge for NACE. All materials meet or exceed ASTM specifications. Model KHR Reflex Gauges can reach pressures up to 4000psig. Model KHT Transparent Gauges can handle pressures up to 3000psig. While these gauges are not specifically designed for steam service, the Model KHR gauges will perform at saturated steam pressures up to 300WSP. The Model KHT will perform at saturated steam pressures up to 750WSP. Mica shields are recommended for Model KHT when used in steam. Shields cannot be used with Reflex Gauges.
FLAT GLASS GAUGE VALVES (GAUGE COCKS)
KENCO Gauge Cocks are designed for use with KENCO Flat Glass Gauges, or gauges from any other manufacturer. All valves are “Offset Pattern” design. This provides for gauge connections that are offset 0.875″ from the centerline of the vessel connections. This allows the gauge to be cleaned by removing vent/drain plugs from the valve. All materials meet or exceed ASTM specifications.
SERIES KMV VALVE STANDARD FEATURES
- Safety Shut-off Ballchecks (Horizontal)
- Integral Bonnet
- Gauge Connection
- Model KMVR — Rigid
- Model KMVU — Union
- Union Vessel Connection
- Integral Seat
SERIES KHV VALVE STANDARD FEATURES
- Safety Shut-off Ballchecks (Horizontal)
- Union Bonnet
- Gauge Connection
- Model KHVR — Rigid
- Model KHVU — Union
- Union Vessel Connection
- Threaded Renewable Seat
PRESSURE/TEMPERATURE RATINGS
- Model KMVx Valves are rated to 2500psig @ 100°F; 1400psig @ 750°F
- Model KHVx Valves are rated to 4000psig @100°F; 1500psig @ 750°F; KHVx valves also carry a steam rating of 450 WSP
OTHER GAUGE ACCESSORIES
Frost Proof Extension
The KENCO Frost-proof Extension is used in low temperature applications where frost has a tendency to build up on the gauge. This extension prevents frost from covering the window, maintaining visibility at all times. The Frost-proof Extension consists of clear, plastic block that is in direct contact with the glass, and extends beyond the cover so that frost build-up does not block the glass. Mounting is easy, and can be added to any Reflex or Transparent gauge in the field. The extension can be installed or removed for cleaning while the gauge is in service.
Gauge Glass Options
KENCO supplies tempered borosilicate glass as standard in all Flat Glass Gauges. Borosilicate glass is suitable for most chemicals, and is good for temperature ranging from -425°F to 600°F (glass rating only). The tempering process improves the thermal shock resistance of the glass. Aluminosilcate glass is offered as an option for higher temperature applications. It offers less thermal expansion, as compared to borosilicate glass. Aluminosilicate glass is good for temperatures ranging from -425°F to 800°F (glass rating only). However, due to the added cost, it is only recommended for temperatures from -600°F to 800°F.
Glass Shields
For corrosive or steam applications, KENCO offers shields to extend the life of the glass in transparent gauges. The shields are made from either PCTFE (Kel-F) or Mica. Mica shields are recommended for steam service. Kel-F shields should be used in corrosive fluid applications. The shield is placed on the process side of the glass. Shields can only be used with transparent gauges.
Thermal Insulators and Gauge Scales
KENCO offers a wide variety of methods to heat or cool gauges in order to maintain the temperature of the process in the gauge. Internal & external heating/cooling tubes, thermal jackets, and insulation blankets are available. Gauge scales can be supplied to provide a numerical reference to the level being measured. Contact KENCO for more information.
