INDUSTRY COMPONENT

Drain Plug

A threaded plug designed for draining hydraulic fluid from reservoirs in industrial machinery.

Component Specifications

Definition
A precision-engineered sealing component installed at the lowest point of hydraulic reservoirs to facilitate complete drainage of hydraulic fluid during maintenance, fluid changes, or system repairs. It features a tapered or flat sealing surface with appropriate thread specifications to prevent leaks under high-pressure conditions.
Working Principle
The drain plug creates a removable seal through threaded engagement with the reservoir body. When tightened, it compresses against a sealing surface (often with a gasket or O-ring) to prevent fluid leakage. During drainage, removal allows gravitational flow of hydraulic fluid through the opening.
Materials
Typically manufactured from carbon steel (AISI 1018/1020), stainless steel (304/316), or brass, often with zinc plating or other corrosion-resistant coatings. Sealing elements may include nitrile rubber (NBR), fluorocarbon (FKM), or polytetrafluoroethylene (PTFE) gaskets.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Size Range1/4" to 1" NPT equivalent
Thread TypeNPT, BSPP, BSPT, or metric threads (e.g., M12x1.5)
Pressure RatingUp to 5000 psi (345 bar)
Temperature Range-40°C to 120°C
Torque Specification15-50 Nm depending on size 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.

Standards
ISO 1179, DIN 3852, SAE J514, ANSI/ASME B1.20.1

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Fluid contamination during drainage
  • Cross-threading during installation
  • Stripped reservoir threads
  • Incomplete sealing causing leaks
  • Over-torquing leading to component failure
FMEA Triads
Trigger: Improper installation torque
Failure: Thread stripping or incomplete seal
Mitigation: Use calibrated torque wrenches and follow manufacturer specifications
Trigger: Corrosion from hydraulic fluid additives
Failure: Seizure making removal impossible
Mitigation: Select compatible materials and apply anti-seize compounds
Trigger: Vibration during operation
Failure: Loosening and catastrophic fluid loss
Mitigation: Implement lock-wire, safety clips, or thread-locking compounds

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance
Thread dimensions per ISO 1179-1 Class B, sealing surface flatness within 0.05mm
Test Method
Pressure testing per ISO 4413, helium leak detection for critical applications, torque-tension relationship verification

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.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Drain Plug

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

SUNPASS SEALING TECHNOLOGY (ZHEJIANG) CO., LTD.
Zhejiang, CN
Listed on the company's own website · profile compiled by CNFX from public sources
HANZHOU CANDID I/E CO.,LTD
Hangzhou, Zhejiang, CN
Listed on the company's own website · profile compiled by CNFX from public sources

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

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Frequently Asked Questions

How often should hydraulic reservoir drain plugs be inspected?

Inspect during every scheduled maintenance interval (typically 250-500 operating hours). Check for thread damage, corrosion, and seal integrity to prevent leaks.

Can drain plugs be reused after removal?

Yes, if threads and sealing surfaces are undamaged. Always replace the sealing gasket/O-ring and apply appropriate thread sealant during reinstallation.

What causes drain plug leaks in hydraulic systems?

Common causes include overtightening (thread stripping), undertightening, damaged sealing surfaces, incorrect thread type, thermal cycling, and chemical degradation of 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.

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