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Clark Reliance Prismatic Level Gages

Clark Reliance Prismatic GageClark 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 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 and "S" Types for pressures to 350 PSI.

Reliance Level gaugeTypical 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 unique Clark Reliance clamping design produces a uniform, firm, strictly compressive load on the glass adding to gage reliability and prolonged service life.

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 1½ 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.

Prismatic glass is flat on the outside.   The inside, in contact with either water or steam, is shaped with multiple 90° angle prisms. Rays of light normal to glass strike the prisms at a 45° angle. The critical angle of a ray passing from glass to steam is 42°. Therefore, the 45° ray is totally reflected and causes the steam space to appear white.

The critical angle of a ray passing from glass to water is 62°. Therefore, with the 45° angle being less, the ray penetrates the water and reveals the gage housing in black.

Click to openGAGE SELECTION DATA
Vertical Centers Prismatic Number Vertical Overall
with Reliance Valves C-Type S-Type Visibility Body Length
14 C4 S4 6-3/4 7-7/8
16 C5 S5 7-7/8 9
17 C6 S6 9-1/8 10-1/4
18 C7 S7 10-1/8 11-3/8
19 C7 S7 10-1/8 11-3/8
19-1/2 C8 S8 11-3/4 13
20 C9 S9 12-1/2 13-3/4
21 C9 S9 12-1/2 13-3/4
22 C9 S9 12-1/2 13-3/4
23 C44 S44 14-7/8 16
24 C44 S44 14-7/8 16
25 C55 S55 17-1/8 18-1/4
26 C55 S55 17-1/8 18-1/4
27 C66 S66 19-5/8 20-3/4
28 C66 S66 19-5/8 20-3/4
29 C66 S66 19-5/8 20-3/4
30 C77 S77 21-3/4 23
31 C77 S77 21-3/4 23
32 C77 S77 21-3/4 23
33 C88 S88 25 26-1/4
34 C99 S99 26-1/2 27-3/4
30-1/4 C444 S444 23 24-1/8
33-5/8 C555 S555 26-3/8 27-1/2
37-3/8 C666 S666 30-1/8 31-1/4
40-3/4 C777 S777 33-3/8 34-5/8
45-5/8 C888 S888 38-1/4 39-1/2
47-7/8 C999 S999 40-1/2 41-3/4
38-3/8 C4444 S4444 31-1/8 32-1/4
42-7/8 C5555 S5555 35-5/8 36-3/4
47-7/8 C6666 S6666 40-5/8 41-3/4
52-3/8 C7777 S7777 45 46-1/4
57-7/8 C8888 S8888 51-1/2 52-3/4
61-7/8 C9999 S9999 54-1/2 55-3/4
Click to openVERTICAL GAGE ASSEMBLIES SELECTION DATA

Vertical Centers With Reliance Valves A

Prismatic Number

Vertical Water Visibility C

Over-All Body Length   B

"C" Type

"S"Type

14

C4

S4

7 -7/8

16

C5

S5

7-7/8

9

17

C6

S6

9-1/8

10-¼

18

C7

S7

10-1/8

11-3/8

19

C7

S7

10-1/8

11-3/8

19-½

C8

S8

11-¾

13

20

C9

S9

12-½

13-¾

21

C9

S9

12-½

13-¾

22

C9

S9

12-½

13-¾

23

C44

S44

14-7/8

16

24

C44

S44

14-7/8

16

25

C55

S55

17-1/8

18-¼

26

C55

S55

17-1/8

18-¼

27

C66

S66

19-5/8

20-¾

28

C66

S66

19-5/8

20-3/4

29

C66

S66

19-5/8

20-3/4

30

C77

S77

21-¾

23

31

C77

S77

21-¾

23

32

C77

S77

21-¾

23

33

C88

S88

25

26-¼

34

C99

S99

26-½

27-¾

30-¼

C444

S444

23

24-1/8

33-5/8

C555

S555

26-¾

27-½

37-3/8

C666

S666

30-1/8

31-¼

40-¾

C777

S777

33-3/8

34-5/8

45-5/8

C888

S888

38-¼

39-½

47-7/8

C999

S999

40-½

41-¾

38-3/8

C4444

S4444

31-1/8

32-¼

42-7/8

C5555

S5555

35-5/8

36-¾

47-7/8

C6666

S6666

40-5/8

41-¾

52-3/8

C7777

S7777

45

46-¼

57-7/8

C8888

S8888

51-½

52-¾

61-7/8

C9999

S9999

54-½

55-¾

Click to openTILTVIEW GAGE ASSEMBLIES SELECTION DATA

Vertical Center With Reliance Valves A

Prismatic Number

Vertical Water Visibility C

Over-All Body Length B

"C"Type

"S"Type

15

C6

S6

7-7/8

10-¼

16

C7

S7

8-¾

11-¾

17

C8

S8

10-¼

13

18

C9

S9

10-7/8

13-¾

19

C9

S9

10-7/8

13-¾

20

C44

S44

12-7/8

16

21

C44

S44

12-7/8

16

22

C55

S55

14-7/8

18-¼

23

C55

S55

14-7/8

18-¼

24

C66

S66

17

20-¾

25

C66

S66

17

20-¾

26

C77

S77

18-7/8

23

27

C77

S77

18-7/8

23

28

C77

S77

18-7/8

23

29

C88

S88

21-5/8

26-¼

30

C99

S99

23

27-¾

 
NOTES ON SPECIFYING CLARK RELIANCE PRISMATIC WATER GAGES

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.

Nipples are ¾" diameter. Minimum length of top nipple is 1¾". Minimum length of bottom nipple is 1¾"  when Clark Reliance bronze valves are used.

PRISMATIC GAGES 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.