In chemical processing, a sight glass —also known as a sight window or viewport— is a transparent component that allows operators to visually inspect the interior of a process pipe or tank. It enables real-time monitoring of liquid levels, media conditions, and process stages without halting operations.
At Douglass, we offer high-quality products for Real-Time Fluid Monitoring, designed with the finest industry-grade components to ensure durability, precision, and reliability. Our solutions provide clear visibility into industrial processes, helping you maintain efficiency, safety, and control. Explore our range of premium sight glasses and monitoring equipment tailored to meet the demands of various industries.
WELD TO TANK
The Douglass ZW15 Weld-to-Tank Sight Glass is a durable and adaptable solution designed for industrial applications requiring clear visibility into tank operations. Built for use in tanks with pressures up to 150 PSI, this sight glass offers a balance of easy installation and a polished, professional look. Its sturdy construction and compatibility with different materials make it suitable for diverse industries, from chemical processingto food and beverage production.
Available in both standard and customizable configurations, the ZW15 ensures it meets specific project requirements while enhancing the overall appearance of the installation.
| Item | Part name | Material options |
|---|---|---|
| 1 | Cover Flange |
|
| 2 | Weld Pad |
|
| 3 | Sight Glass (max temp) |
|
| 4 | Gaskets *(max temp) |
|
| 5 | Bolts |
|
| ZW15-2 | ZW15-3 | ZW15-4 | ZW15-5 | ZW15-6 | ZW15-7 | ZW15-8 | |
|---|---|---|---|---|---|---|---|
| Visible Diameter (A) | 2" | 3" | 4" | 5" | 6" | 7" | 8" |
| Total Diameter (B) | 4" | 5" | 6" | 7-1/2" | 9" | 10" | 11" |
| ZW15-2 | ZW15-3 | ZW15-4 | ZW15-5 | ZW15-6 | ZW15-7 | ZW15-8 | |
|---|---|---|---|---|---|---|---|
| Cover (H1) | 5/8" | 5/8" | 5/8" | 3/4" | 3/4" | 1" | 1" |
| Weld Pad (H2) | 3/4" | 3/4" | 3/4" | 1" | 1" | 1-1/4" | 1-1/4" |
| ZW15-2 | ZW15-3 | ZW15-4 | ZW15-5 | ZW15-6 | ZW15-7 | ZW15-8 | |
|---|---|---|---|---|---|---|---|
| Ø | 2-3/4" | 3-3/4" | 4-3/4" | 6" | 7" | 8" | 9" |
| Thickness | 5/8" | 5/8" | 3/4" | 3/4" | 3/4" | 1" | 1" |
| ZW15-2 | ZW15-3 | ZW15-4 | ZW15-5 | ZW15-6 | ZW15-7 | ZW15-8 | |
|---|---|---|---|---|---|---|---|
| Bolt Circle Diameter (C) | 3-3/8" | 4-3/8" | 5-3/8" | 6-3/4" | 8" | 9" | 10" |
| Tightening Torque (ft/lbs) | 17 | 17 | 19 | 19 | 21 | 25 | 25 |
WELD TO TANK
The Douglass ZW30 Weld-to-Tank Sight Glass is a high-performance solution designed for demanding industrial applications requiring enhanced durability and higher pressure ratings. Suitable for tanks operating up to 300 PSI, the ZW30 is engineered to provide clear, reliable visibility into tank processes while withstanding the rigors of more intensive environments. Its robust construction allows for greater torque application, making it ideal for use with metal-inserted gaskets.
| Item | Part name | Material options |
|---|---|---|
| 1 | Cover Flange |
|
| 2 | Weld Pad |
|
| 3 | Sight Glass (max temp) |
|
| 4 | Gaskets *(max temp) |
|
| 5 | Bolts |
|
| ZW30-2 | ZW30-3 | ZW30-4 | ZW30-5 | ZW30-6 | ZW30-7 | ZW30-8 | |
|---|---|---|---|---|---|---|---|
| Visible Diameter (A) | 2" | 3" | 4" | 5" | 6" | 7" | 8" |
| Total Diameter (B) | 5" | 6" | 7" | 8-1/2" | 10" | 11" | 13" |
| ZW30-2 | ZW30-3 | ZW30-4 | ZW30-5 | ZW30-6 | ZW30-7 | ZW30-8 | |
|---|---|---|---|---|---|---|---|
| Cover (H1) | 3/4" | 3/4" | 3/4" | 1" | 1-1/4" | 1-1/4" | 1-1/2" |
| Weld Pad (H2) | 1" | 1" | 1" | 1-1/4" | 1-1/2" | 1-1/4" | 1-1/2" |
| ZW30-2 | ZW30-3 | ZW30-4 | ZW30-5 | ZW30-6 | ZW30-7 | ZW30-8 | |
|---|---|---|---|---|---|---|---|
| Ø | 3-3/4" | 4-3/4" | 5-3/4" | 7" | 8" | 9" | 11" |
| Thickness | 3/4" | 3/4" | 1" | 3/4" | 1-1/4" | 1-1/4" | 1-1/4" |
| ZW30-2 | ZW30-3 | ZW30-4 | ZW30-5 | ZW30-6 | ZW30-7 | ZW30-8 | |
|---|---|---|---|---|---|---|---|
| Bolt Circle Diameter (C) | 3-3/8" | 4-3/8" | 6-3/8" | 7-3/4" | 9" | 10" | 12" |
| Tightening Torque (ft/lbs) | 17 | 17 | 19 | 22 | 25 | 28 | 32 |
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Please feel free to contact us with any questions or comments you may have. We would love to hear from you!