Sight Glass/Level Indicator: Temperature Range -20°C to 120°C

Component Specifications

Definition

A sight glass or level indicator is a transparent window or gauge installed on coolant reservoirs to provide visual monitoring of fluid levels, temperature, and condition without opening the system. It enables operators to maintain optimal coolant levels for efficient heat transfer and equipment protection in industrial machinery.

Working Principle

Operates through transparent material (typically glass or polycarbonate) that allows direct visual observation of fluid levels against calibrated markings. Some advanced versions incorporate magnetic floats, electronic sensors, or temperature indicators for enhanced monitoring capabilities.

Materials

Body: Stainless steel (304/316), aluminum, or brass; Window: Tempered glass, borosilicate glass, or polycarbonate; Seals: EPDM, Viton, or silicone gaskets; Optional: Magnetic float (stainless steel with magnet)

Technical Parameters

Parameter	Typical range	Notes & selection driver
Accuracy	±2 mm
Visibility	360° or 180° viewing angle
Connection Type	Threaded (NPT, BSP), Flanged
Pressure Rating	0-10 bar
Window Diameter	25-100 mm
Temperature Range	-20°C to 120°C

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

Standards

ISO 9001, DIN 11851, ASME B31.3

Parent Products

This component is used in the following industrial products

Coolant Reservoir

A container that stores and supplies coolant fluid within a water cooling system.

View Product Details

Coolant Tank/Reservoir

The coolant tank or reservoir is a critical component of coolant systems that serves as a storage and supply vessel for coolant fluid.

View Product Details

Engineering Analysis

Risks & Mitigation

Visual obstruction from clouding
Seal failure leading to leaks
Window cracking under pressure/temperature extremes
Inaccurate readings due to parallax error
Chemical incompatibility with fluids

FMEA Triads

Trigger: Thermal stress from rapid temperature changes
Failure: Window cracking or seal degradation
Mitigation: Use tempered or borosilicate glass with proper thickness; install thermal shields; implement gradual temperature changes

Trigger: Chemical attack from incompatible coolants
Failure: Window clouding, discoloration, or material degradation
Mitigation: Select chemically resistant materials (borosilicate glass, specific polymers); verify coolant compatibility; implement regular inspection schedules

Trigger: Mechanical impact or vibration
Failure: Window breakage or connection loosening
Mitigation: Install protective guards; use shock-absorbing mounts; specify impact-resistant materials like polycarbonate for high-vibration environments

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Level indication accuracy within ±2% of full scale; Pressure rating must exceed maximum system pressure by 25%

Test Method

Hydrostatic pressure testing per ISO 9001; Visual inspection for clarity and marking permanence; Material compatibility testing with specified coolants

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

Compare the published product scope and source details, then include your specifications and quantity in an enquiry.

Manufacturers of Sight Glass/Level Indicator

1 company lists this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Tianjin U-ideal Instrument Co., Ltd.

Tianjin, CN

Also makes: Level Indicator, Level Controller, Viewing Port and 1 more

Listed on the company's own website · profile compiled by CNFX from public sources

Listed there as: “Reflex (reflective) Sight Glass Level indicator”
View source page ↗ china-flow-meters.com · recorded 2026-09-14

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Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

How often should sight glass on coolant reservoirs be inspected?

Daily visual inspections are recommended during machine operation checks. Complete cleaning and seal inspection should occur during scheduled maintenance, typically every 3-6 months depending on coolant type and operating conditions.

What causes sight glass clouding or discoloration?

Clouding typically results from chemical degradation of the window material due to incompatible coolants, excessive heat exposure, or UV radiation. Discoloration may indicate coolant contamination or chemical reactions between the fluid and window material.

Can sight glasses be used with all types of industrial coolants?

Most standard sight glasses are compatible with water-based coolants and oils. For aggressive chemicals or extreme temperatures, specify borosilicate glass or specialized polycarbonate windows with chemical-resistant seals.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Sight Glass/Level Indicator