Description
API Plan 32 supplies a clean, compatible external liquid directly into the seal chamber to improve the operating environment around the mechanical seal faces. The injected flush dilutes or displaces abrasive particles, suspended solids, polymerizing compounds, oxidizing contaminants, or vapors that may otherwise damage the seal faces, restrict face cooling, or cause unstable seal operation.
This plan is typically selected where the pumped fluid is unsuitable for internal circulation because it is dirty, hot, crystallizing, viscous, polymerizing, or contaminated. It is also used where the process can accept dilution from an external flush source and where the seal chamber must be pressurized to reduce flashing, vapor formation, or air intrusion in vacuum service.
Key Features
- · Provides a clean external flush directly to the mechanical seal chamber.
- · Improves seal-face cooling and lubrication in hot or poor-lubricity services.
- · Suitable for vacuum services where positive flush pressure reduces air ingress.
- · Compatible with single mechanical seals in API-style pump sealing arrangements.
- · Supports stable seal operation where pumped media may flash, vaporize, or crystallize.
- · Helps exclude solids, contaminants, pulp fibres, and polymerizing residues from the seal faces.
- · Allows controlled flush regulation using a strainer, flow meter, control valve, pressure indicator, and temperature indicator.
Service Overview
| Parameter | Value |
|---|---|
| Equipment | Centrifugal pumps, process pumps, paper stock pumps, slurry-handling pumps, high-temperature process pumps |
| Fluid | Dirty or contaminated liquids, paper pulp, fluids with solids, oxidizing fluids, polymerizing media, hot process liquids |
| Service Nature | External clean flush injection into the seal chamber |
| Operating Mode | Continuous controlled flush with regulated pressure and flow |
Specifications
| Item | Min | Max | Typical / Notes |
|---|---|---|---|
| Size | 6 mm / 0.250” tubing | 25 mm / 1.000” tubing | Final line size selected by seal size, flush rate, and site standard |
| Pressure | Seal chamber pressure + 2 bar (29 psi) | 38 bar (551 psi) system design pressure | Flush pressure must remain above seal chamber pressure |
| Temp | -20°C (-4°F) | +140°C (+284°F) | Flush liquid should be compatible and cool enough to remove seal heat |
| Speed | Equipment dependent | Equipment dependent | Applicable to single seals where Plan 32 flush is suitable |
Materials
| Component | Standard Material | Optional Material | Comment |
|---|---|---|---|
| Tubing / Pipework | SS 316 | SS 304, Duplex SS, Alloy 20, Hastelloy | Select based on flush liquid and site corrosion requirements |
| Control Valve | SS 316 needle/globe valve | Alloy construction | Used for flush-flow regulation |
| Flow Meter | SS 316 body with glass/metal tube | Digital flow transmitter | Recommended for reliable flush verification |
| Strainer | SS 316 Y-strainer | Duplex SS, Hastelloy | Protects the restriction or control valve from blockage |
| Instruments | Pressure indicator, temperature indicator | Pressure/temperature transmitters | Optional monitoring for critical services |
| Connections | NPT / BSP / flanged | Compression fittings, welded fittings | Selected to suit the pump gland and plant standard |
Applications
- · Dirty or contaminated process-fluid services.
- · Polymerizing, oxidizing, or crystallizing liquid services.
- · Paper and pulp processing pumps handling fibrous stock.
- · Slurry or solids-bearing fluids where the process permits dilution.
- · High-temperature pump seal chambers requiring external cooling flush.
- · Chemical, petrochemical, paper, refinery, and general process industries.
- · Vacuum services requiring a positive seal-chamber flush to reduce air intrusion.
Operating Limits
| Parameter | Value |
|---|---|
| Pressure | Up to 38 bar (551 psi); flush supply maintained at least 2 bar (29 psi) above seal chamber pressure |
| Temp | -20°C to +140°C (-4°F to +284°F); flush liquid must remain compatible and non-vaporizing at service conditions |
| Speed | Equipment dependent; governed by selected mechanical seal and pump speed |
| Size Range | Typically, 6 mm to 25 mm / 0.250” to 1.000” (inch series) flush piping/tubing |
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