Level Gauge / Sight Glass for Recovery Tanks | Specifications & Verification

Product Specifications

Technical details and manufacturing context for Level Gauge or Sight Glass

Definition

A level gauge or sight glass is a monitoring component installed on recovery tanks to provide operators with a direct visual indication of the liquid level within the vessel. It is essential for safe and efficient operation, helping to prevent overfilling or running dry, which could damage equipment or disrupt processes. The device typically consists of a transparent window or a float mechanism connected to an external scale. Materials commonly used include tempered glass, stainless steel, polycarbonate, and acrylic, chosen based on the application's pressure, temperature, and chemical compatibility. Key parameters to consider include nominal diameter (DN15–DN50 per ISO 6708), operating pressure (1.0–1.6 MPa), operating temperature (-20 to 150°C), material grade (304 or 316L per ASTM A240), glass thickness (15–20 mm), visibility length (100–500 mm), connection type (flange or thread per GB/T 9119), accuracy (±5 mm), and weight (2–8 kg). These values are reference ranges and must be verified for the specific model and application. The level gauge is typically connected via flanged or threaded connections, and the visibility length determines the range of liquid level that can be observed. For corrosive media, 316L stainless steel is recommended. The device operates on the principle of direct line of sight through a transparent window or via a float that moves a pointer on a calibrated scale. Regular inspection is necessary to detect clouding, cracking, or leakage. If the glass becomes damaged or the float mechanism sticks, the gauge should be replaced immediately. Always confirm model-specific values and standards with the legal manufacturer or supplier before installation.

Working Principle

The level gauge operates by providing a direct line of sight to the liquid inside the tank through a transparent window (sight glass) or by using a float mechanism connected to an external gauge. In the sight glass type, the liquid level is visible through a transparent tube or window, allowing the operator to read the level directly. In the float type, a float rests on the liquid surface and moves a pointer or indicator along a calibrated scale, translating the liquid level into a readable measurement. The device must be installed at the correct height and orientation to ensure accurate readings. The operating pressure and temperature must be within the specified ranges to prevent glass failure or seal leakage. The accuracy of the reading is typically ±5 mm, which is sufficient for most monitoring applications. The choice of material and glass thickness depends on the pressure and the nature of the media. For high-pressure or corrosive applications, thicker glass and stainless steel construction are recommended. Regular maintenance includes cleaning the glass and checking for any signs of wear or damage.

Common Materials

Tempered Glass, Stainless Steel, Polycarbonate, Acrylic

Technical Parameters

Parameter	Typical range	Notes & selection driver
Nominal Diameter	DN15–DN50 mm	Standard pipe sizes for connectionISO 6708
Operating Pressure	1.0–1.6 MPa	Below 1.0 MPa seat load insufficientISO 5208
Operating Temperature	-20–150 °C	Above 150°C gasket may fail
Material	304/316L	316L for corrosive mediaASTM A240
Glass Thickness	15–20 mm	Thicker for higher pressure
Visibility Length	100–500 mm	Custom lengths available
Connection Type	Flange/Thread	Flange per GB or ANSIGB/T 9119
Accuracy	±5 mm	Visual reading tolerance
Weight	2–8 kg	Depends on length and material

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Viewing Window/Glass Part
Provides a transparent medium to see the liquid level.

Material: Tempered Glass or Polycarbonate
Gasket/Seal Part
Ensures a pressure-tight seal between the glass and the housing.

Material: PTFE, Viton, or EPDM
Housing/Frame Part
Holds the glass and provides mounting points to the tank.

Material: Stainless Steel or Cast Iron
Protective Guard (Optional) Optional Part
Shields the glass from physical impact.

Material: Stainless Steel

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Recovery Tank

View system integration details

Manufacturers of Level Gauge or Sight Glass

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Frequently Asked Questions

What is the typical accuracy of a level gauge?

The typical accuracy is ±5 mm, as listed in the reference parameters. This tolerance is for visual reading and may vary depending on the installation and the specific model. Always verify the accuracy with the manufacturer for your application.

Can the level gauge be used for corrosive media?

Yes, for corrosive media, the material grade should be 316L stainless steel, as indicated in the reference parameters. The glass and seals must also be compatible with the media. Confirm material compatibility with the supplier.

What are the standard connection types?

The standard connection types are flange or thread, per GB/T 9119. The nominal diameter ranges from DN15 to DN50. Ensure the connection type matches your tank's existing fittings.

How do I know if the level gauge needs replacement?

Signs of failure include clouding or cracking of the glass, leakage at the seals, or a stuck float mechanism. If the reading becomes unreliable or the device shows physical damage, replace it immediately. Regular inspection is recommended.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

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pressure:	Vacuum to 25 bar (standard), up to 100 bar with reinforced construction
other spec:	Flow Rate: Not applicable (static measurement), Slurry Concentration: Limited to <10% solids for clear visibility, Viscosity: All ranges, but may require heating jackets for viscous fluids
temperature:	-40°C to 200°C (typical), up to 400°C with special glass/design

Level Gauge or Sight Glass

Product Specifications

Applied To / Applications

Industrial Ecosystem & Supply Chain Structure

Application Fit & Sizing Matrix

Reliability & Engineering Risk Analysis

Compliance & Manufacturing Standards