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Transparent Sight Glass

Transparent Sight Glass

Transparent Sight Glass

Polycarbonate Level Tube

Polycarbonate tubes in level gauges offer a combination of durability and optical clarity, making them an excellent choice for fluid level monitoring across various applications. This tough thermoplastic is easy to handle at high temperatures and is widely used in modern manufacturing due to its outstanding properties and resistance to chemicals.

These tubes are commonly utilized in fluid level monitoring systemswhere there is a risk of breakage from impact or vibration. As an FDA-approved material, polycarbonate is widely employed in water treatment, food and beverage processing, as well as the chemical and pharmaceutical industries.

Transparent Sight Glass

TECHNICAL INFORMATION

Glass typePolycarbonate
Outside diameter1/2", 5/8", 3/4", 1", 1-1/2", 2", 2-1/4", 3", 3-1/2", 4"
Wall thicknessVaries by O.D. (see chart below)
Minimum length1"
Maximum length145"
Maximum working temperature120°C
Minimum working temperature−40°C
Thermal shock resistance60 K
Maximum working pressureConsult a Douglass representative
Thermal expansion coefficient70 × 10⁻⁶ / K
Fragilization temperature−175°C
Chemical resistanceVaries by chemical (see chart below)

AVAILABLE SIZES

Outside diameterWall thicknessOutside diameterWall thickness
1/2"1/8"2"3/16"
5/8"1/8"2-1/4"3/16"
3/4"1/8"3"1/4"
1"1/8"3-1/2"1/4"
1-1/2"3/16"4"1/4"

Tempered Borosilicate Level

Sight Glasses DIN7081 - Reflex

Reflex level gauge glasses, made out of borosilicate, are a critical tool in various industrial applications, offering a simple yet effective method to visually monitor the liquid level within tanks and vessels.

These devices utilize a series of prisms embedded in the glass that reflect light differently depending on whether they are in contact with a liquid or gas. When the liquid level is present, the prisms in contact with the liquid allow light to pass through, making the liquid level appear dark against a silvery background. Conversely, in areas where no liquid is present, the prisms reflect light, making these sections appear bright.

This clear visual contrast provides an immediate and accurate indication of the fluid level, facilitating safe and efficient process managementin industries such as chemical manufacturing, petroleum refining, and power generation, where precise level measurement is crucial for operational safety and efficiency.

Transparent Sight Glass

Crystal length l by size

THK bRD r2345678m91011
30 mm15 mm140 mm165 mm190 mm220 mm250 mm280 mm320 mm340 mm370 mm400 mm
34 mm17 mm5-1/2"6-1/2"7-1/2"8-5/8"9-7/8"11"12-5/8"13-3/8"370 mm400 mm

Chemical properties

PropertySpecification
Hydrolytic resistanceHGB 1 (ISO 719)
Acid resistanceCLASS S1 (ISO 1776)
Alkaline resistanceCLASS A2 (ISO 695)
SiO₂Min 80% content
B₂O₃Min 13% content
Na₂O + K₂OMin 4.5% content

Tempered Borosilicate Level

Sight Glasses DIN7081 - Transparent

High-pressure transparent level gauge glasses, serve as an indispensable tool in environments where monitoring the exact level of fluids under high pressure is critical.

Unlike their reflex counterparts, these gauges employ two pieces of flat, transparent glass mounted on opposite sides of a tank or vessel, allowing operators to observe the fluid level directly. This design is particularly advantageous in applications where it’s essential to view the characteristics of the fluid itself, such as color, clarity, and the presence of any sediments or separations.

The straightforward, yet effective, visibility provided by these gauges makes them a key component in maintaining operational safety and efficiency, ensuring precise fluid management in even the most demanding industrial settings.

Transparent Sight Glass

Crystal length l by size (DIN 7081 reference)

THK bRD r2345678m91011
1.18"0.59"140 mm165 mm190 mm220 mm250 mm280 mm320 mm340 mm370 mm400 mm
1.34"0.67"5-1/2"6-1/2"7-1/2"8-5/8"9-7/8"11"12-5/8"13-3/8"

Chemical properties

PropertySpecification
Hydrolytic ResistanceHGB 1 (ISO 719)
Acid ResistanceCLASS S1 (ISO 1776)
Alkaline ResistanceCLASS A2 (ISO 695)
SiO₂Minimum content 80%
B₂O₃Minimum content 13%
Na₂O + K₂OMinimum content 4.5%

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