Reliance® Prismatic (Reflex) Water Gage Glasses

Sharp, Highly Visitble, Accurate Water Level Readings

Sharp, Highly Visible, Accurate Water Level Readings

Precise, Easy-To-Read Level Gages Meet A Wide Variety of Installation Requirements

Clark-Reliance Prismatic Gages provide a well-defined, distinct image of water levels, eliminating reading errors or distortions possible with less effective gage types.  Highly versatile, Prismatic Gages are easily installed in vertical or Tiltview Assemblies.  In addition, Clark-Reliance Prismatic Gages are easily installed in vertical or Tiltview Assemblies.  In addition, Clark-Reliance Prismatic Gages offer the flexibility of combining multiple gage sections to achieve coverage of extended viewing areas.

Available in two designs, “C” Types should be specified for pressures to 250 PSI (17 Bar) and “S” Types for pressures to 350 PSI (23 Bar).

Typical Prismatic Gage applications include installation on boiler drums, feedwater heaters, deaerators, and other tanks.

Quality Materials
 Clark-Reliance Prismatic Gages feature quality materials and reliable design.  Gage glass is of the highest quality borosilicate glass, tempered for improved toughness against shattering.  As an important safety feature, should breakage occur, glass fragments will interlock and remain in place.

The Prismatic Principle

Multiple Sections Allow Longer Level Viewing Areas

Large storage tanks, heater tanks and similar applications call for Prismatic Gage assemblies employing multiple gage sections.  Double, triple and quadruple assemblies are readily available, and even longer assemblies can be provided.

In multiple assemblies, the space between gage windows is approximately 1-1/2 inches.  This gap is considered insignificant where multiple assemblies are normally installed.

Note the various dimensions and specifications for multiple gage assemblies listed in tables presented elsewhere on these pages.

multiple section gages




prismatic water gages

10-27C Type



Specific combinations of boiler water pressure and boiler water pH levels suggest the installation of mica-protected gages to resist gage glass deterioration and possible gage leakage.

gage selection data



prismatic vertical assemblies

prismatic pricebook

*Available in “S” Type Only




prismatic tiltview

tiltview sizing


    • When specifying Prismatic Gages, refer to the Vertical Valve Center dimension “A” in the tables provided.  Locate the “A” dimension that corresponds to your own gage valve centers.
    • The over-all length of the Prismatic Gage, including nipples, is equal to a Tubular Glass gage length.
    • A change to Prismatic Gages reduces the length of visible water range 3″ to 6″ depending upon gage and valve combinations.
    • Gage nipples are 3/4″ diameter.  Minimum length of top nipple is 1-3/4″.  Minimum length of bottom nipple is 1-3/8″ when Clark-Reliance bronze valves are used.




REPLACING tubular glass

NOTE: When installing a Prismatic Gage to replace an existing tubular glass gage, a reduction in gage visibility can be avoided by installing an offset assembly.  The offset assembly accepts a Prismatic Gage long enough to provide the necessary visibility, using valves rotated 90°.  When ordering, please specify gage valve centers and Clark-Reliance Water Column and Valve part Numbers.

valve centers