John Crane 3-4036-004C Pump Mechanical Seal Unit

Module Feature

3-4036-004C is John Crane industrial single spring balanced mechanical seal, widely used for centrifugal process pump overhaul replacement. It adopts carbon rotating face paired with silicon carbide stationary seat, Viton O-ring elastomer, good chemical compatibility for water, oil and light chemical medium. Balanced design reduces pressure load on sealing face, suitable for medium high pressure working condition. It can be installed as component seal or cartridge assembly. Widely used in chemical, water treatment, oil and gas transfer pump.

Working principle

Spring force pushes rotating seal face to closely fit stationary seat, forming thin liquid film between two lapped faces to realize sealing. The balanced structure offsets part of medium pressure to reduce face specific pressure, extend service life. The O-ring provides static sealing between seal ring and shaft/sleeve. Once face wear or elastomer aging occurs, medium leakage will appear.

Onboard components

Carbon rotating ring, silicon carbide stationary seat, stainless steel single compression spring, Viton O-rings, drive pin, anti-rotation stop component.

LED indicators

No built-in indicator lamp. Seal failure is judged by visible medium leakage and pump packing box drip.

Hardware self‑diagnosis

No electronic self-check. Fault judgment relies on visual leakage, pressure holding and periodic disassembly inspection.

Programming software

Not applicable.

Electrical & Process Parameters

Model:3-4036-004C Brand:John Crane Device type:Balanced Mechanical Shaft Seal Face material:Carbon / Silicon Carbide Elastomer:Viton Media:Clean water, mineral oil, light process chemical Function:Shaft sealing of centrifugal pump, prevent medium leakage along shaft

Mechanical & Structure

Mounting:Installed on pump shaft sleeve inside seal chamber Protection class:IP55 after assembly Housing:Multiple precision sealing components

Environmental

Operating temperature:-20℃ ~ +180℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing Certification:API682 optional compliant Status:John Crane original mechanical seal spare

Installation

Clean shaft sleeve, seal chamber and all parts completely before assembly. Protect lapped sealing face from scratch. Install O-ring and seal ring in sequence, set spring compression according to drawing requirement. After pump assembly, fill flush fluid and check leakage. Replace regularly when face pitting or elastomer swelling occurs.

Interface

Inner bore matches pump shaft sleeve, sealing face contacts stationary seat, flush port interface for flush plan.

Diagnostic

Continuous medium leakage: Seal face scratched, spring fatigue loss of compression, O-ring chemical swelling.

Short service life: Flush fluid interrupt, solid particle abrasive wear on sealing face.

Seal heat and smoke: Dry running without liquid film.

Product BriefJohn Crane 3-4036-004C balanced mechanical seal, carbon silicon carbide face, Viton seal, single spring structure, used for industrial centrifugal pump shaft sealing.