Tubular Sight Glass

Tubular Sight Glass

Tubular sight glass (also called ‘tubular gauge glass’) is found on the outside of a boiler or tank and it provides a simple and efficient way to view the liquid level within the structure. It fits between an upper and lower gauge glass valve which in turn is mounted on the structure.

Available Tubular Sight-Glass

Scroll through the chart before to locate the part number and technical data for the type of glass you are looking for. Please contact us for price and availability.

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Do you have questions about tubular gauge glass?

To help us get you pricing and availability please have the following info:

  • Glass length
  • Glass O.D. (1/2″, 5/8″ or 3/4″)
  • High-Pressure or Heavy Wall thickness
  • Clear or Red-Line

You can refer to the chart above for technical data and to see what’s available.

We do our absolute best to package glass safely for transportation and to make our courier’s aware that they are handling a fragile glass product. However, ultimately we are shipping glass and Keystone cannot guarantee safe arrival. 

If we are shipping locally within the GTA, we ship via MadDash, a small local courier. This is helpful as the glass does not have to change hands much or have to go through large  transport depots. Often, the driver will pickup, put the glass in the backseat of their car and deliver it straight to you, fully aware they are moving glass.

If we are shipping outside of the GTA we package the glass tubes inside of PVC tubing and surround it with packaging peanuts. We put many fragile stickers on the box and ask the courier not to put it on the belt at the depot.

In the end, if glass does break in transit there are no refunds and you will have to place a new order. We encourage customers to come pickup glass from us directly, whenever possible. Alternatively, consider ordering polycarbonate tubing if you are far away from us as it is much safer to ship.

The borosilicate glass used to manufacture these products is outstanding for chemical services. Certain limitations, however, must be recognized. Some materials reduce the useful life of the gage glass by chemical action: e.g. hydrofluoric acid (HF); hot  concentrated phosphoric acid; sodium and potassium hydroxides above 125 ̊F; steam or
superheated water above 250 ̊F.

Alkaline solutions attack glass very slowly at room temperatures, but as temperature is increased over 100 ̊F, the corrosion rate rises rapidly.

High pressure sight glass can be used for low pressure boilers,  restaurant equipment, closed tanks, liquid level gages, sight flow, film rolls hydraulic equipment. It offers visual indication of liquid flow, contamination or discoloration of liquid, metering a constant rate of flow through a fixed port. As well as a long service life.

Heavy wall glass can be used in crude oil, water or gas flowmeters. It permits stable and reliable operation with better viewing of oil, water or gas flow rates.

The red line shaded with white lines make it easier to read the liquid level (on heavy wall red-line glass only).

Keystone supplies washers and valve sets for new gauge glass installations. If you are replacing glass on an existing installation you may also wish to purchase new EPDM washers if the old ones are worn out. 

If you want to cut your own glass, we also sell Wheeler-Rex sight glass cutters. If you often need smaller pieces of glass this option can ultimately save you money. Purchase longer stock pieces of glass in advance and then cut them down yourself as you need them.

Finally, we also sell Gauge Glass Guardian; a polycarbonate protective shield designed to prevent sight glass from accidentally breaking.