Product Introduction – Transformer Oil Drainage/Sampling Flange Valve

I. Product Overview

The transformer oil drainage/sampling flange valve is a specially designed valve assembly installed at the bottom or side of a power transformer tank. Its core functions are the safe and controlled drainage of transformer insulating oil or the extraction of oil samples, while ensuring absolute sealing during normal transformer operation to prevent oil leakage and the ingress of air and moisture.

It is an indispensable critical component for transformer maintenance, repair, oil testing, and emergency incident handling.

II. Primary Structure 

Typical Structure:

Valve Body:​ Typically made of cast iron, copper, or stainless steel, providing sufficient mechanical strength and oil resistance.

Disc/Valve Core:​ Often brass or stainless steel, designed as a rotary type (e.g., butterfly) or plunger type to ensure effective sealing and flow capacity.

Sealing Components:​ Utilize oil-resistant, high-temperature resistant, and aging-resistant sealing rings made of materials like Nitrile Butadiene Rubber (NBR) or Fluorocarbon Rubber (FKM) to guarantee long-term sealing performance.

Operating Lever/Handwheel:​ The external operating mechanism, usually featuring “Open/Close” indicators. Higher-end models may include a lockable handle or a chained wrench to prevent accidental operation.

Flange Connection:​ Both ends of the valve feature standard flanges (e.g., GB, ANSI, DIN standards) for easy connection to the transformer tank and external piping.

Sampling/Drainage Nozzle:​ The valve outlet typically features an internal thread or quick-connect coupling for attaching drainage hoses or specialized sample bottles.

III. Core Functions and Applications

Insulating Oil Sampling:​ Used for extracting oil samples during routine testing or for fault analysis. This enables key tests such as Dissolved Gas Analysis (DGA), moisture content, breakdown voltage, and dielectric dissipation factor, which are the most important means of assessing the internal health of a transformer (e.g., overheating, discharge, insulation degradation).

Transformer Maintenance and Oil Replacement:​ Serves as the oil inlet/outlet point when filtering, replenishing, or replacing the insulating oil.

Transformer Inspection/Overhaul:​ Used to drain oil from the tank into a storage vessel prior to core inspection or major internal work.

Emergency Oil Drainage:​ In the event of a severe internal fault (e.g., fire, oil eruption), it allows for rapid oil drainage into a designated containment pit to prevent fire escalation and environmental contamination.

Bottom Sediment and Water Drainage:​ Allows for the removal of trace amounts of accumulated water and particulate matter from the bottom of the tank.

IV. Key Features and Advantages

1.High Sealing Reliability:​ A dual-seal design ensures zero leakage throughout the transformer’s extended operational life (potentially decades), helping maintain a slight internal positive pressure to prevent insulating oil from absorbing moisture and oxidizing.

2.Simple and Safe Operation:​ A 90-degree rotation opens or closes the valve, requiring minimal operating torque. Clear open/close indicators and safeguards against accidental operation enhance personnel safety.

3.Low Flow Resistance Design:​ When fully open, the disc/valve core presents minimal obstruction to oil flow, enabling fast drainage and high efficiency.

4.Excellent Material Compatibility:​ All materials in contact with the insulating oil (metals, seals) are fully compatible, preventing corrosion or the generation of substances that could catalyze oil aging.

5.Robust and Durable Construction:​ Withstands vibration, thermal expansion/contraction, and potential internal pressure fluctuations during transformer operation.

6.Standardized Connections:​ Flange dimensions comply with international or national standards, ensuring good interchangeability and ease of installation/connection to external equipment