RPW-021 Single Coil Spring – Durable and Reliable
RPW-021 Single Coil Spring – Durable and Reliable
Overview
HydroMax Seal RPW-021 | Uni-Directional Single Coil Spring Seal with PTFE ‘V’ Packing
The RPW-021 is a unidirectional single coil spring mechanical seal featuring a shrink-fitted rotary head and PTFE ‘V’ packing for superior chemical resistance. Designed for parallel shafts, this seal includes a set screw drive system and is supplied in standard working lengths for consistent installation and reliable operation.
Engineered for internal wet service, the RPW-021 provides robust sealing performance in applications requiring low friction and high compatibility with aggressive media.
Product Description
Design Features
- Uni-directional single spring configuration
- Shrink-fitted rotary head ensures secure fit and stable sealing
- Parallel shaft design with PTFE ‘V’ packing for enhanced chemical resistance
- Set screw driven for positive torque transmission
- Ideal for internal wet applications in chemically aggressive environments
Technical Specifications
| Seal Shaft Sizes | 1.000″ – 4.000″ (12mm – 100mm) |
| Inboard Seal Face Combination | Car/TC Car/SiC |
| Elastomers | V-Packing (PTFE) |
| Shaft Speeds | Up to 10 m/s |
| Pressures | Up to 8 Barg (116 psig) – Shaft Size Specific |
HydroMax Seal RPW-021 is a reliable sealing solution designed for unidirectional rotating equipment in chemical, pharmaceutical, and light industrial applications.
Typical Applications & Industry Use Cases
The RPW-021 Single Coil Spring Mechanical Seal is a simple and reliable internal wet seal designed for parallel-shaft rotating equipment. It features a single helical coil spring and elastomeric secondary seals for effective sealing in general industrial fluid services. The set-screw drive provides secure mechanical engagement, making the RPW-021 suitable for applications that require straightforward sealing without complex support systems.
Industries Served
Water and wastewater treatment
Chemical and petrochemical processing
Industrial process pumping
HVAC and building services
Agricultural and irrigation systems
Manufacturing and fluid transfer operations
Equipment & Use-Case Scenarios
- Parallel-shaft centrifugal and process pumps require basic internal sealing
- Services with clean to moderately contaminated liquids
- Applications under low to moderate pressure and temperature conditions
- Routine maintenance and part replacement in standard pumping systems
Why It Fits These Applications
- Single coil spring design: Maintains consistent radial load to keep seal faces in contact
- Elastomeric secondary seals: Provide dependable sealing to shaft and housing surfaces
- Set-screw drive: Ensures secure mechanical engagement and simplifies installation
- Internal wet configuration: Utilises the process fluid for lubrication and heat dissipation
- Straightforward construction: Ideal choice where cost-effective, no-frills sealing is adequate
Installation Guidelines
Pre-Installation Preparation
Clean and inspect the pump shaft, seal chamber bore, and gland surfaces. Remove corrosion, debris, and surface imperfections to ensure good sealing surface contact and proper alignment.
Seal Installation
Slide the RPW-021 seal onto the shaft into the seal chamber. Position the coil spring and elastomer components correctly relative to the shaft and housing. Tighten the set screws evenly to secure the seal without over-torquing.
Orientation Check
Verify that the seal’s orientation matches the direction of shaft rotation and fluid flow where applicable.
System Readiness
Confirm that the seal chamber is flooded with process fluid if required and that all components are securely in place before starting the equipment.
Maintenance & Inspection Best Practices
- Routine Visual Checks: Periodically inspect the seal area for leakage, unusual vibration, or temperature variation
- Seal Face Condition: Check seal faces during scheduled maintenance for wear, scoring, or deposits
- Secondary Seal Care: Inspect elastomeric O-rings and replace if hardened, cracked, or deformed
- Operating Logs: Keep records of pressure, temperature, and shaft speed to assist predictive maintenance
- Spare Parts Inventory: Maintain replacement springs, secondary seals, and seal faces to minimise downtime
Service & Support Options
- Application Review: Confirm elastomer compatibility and overall seal selection based on fluid chemistry and operating conditions
- Installation Assistance: Guidance to help ensure correct orientation and secure engagement
- Preventive Maintenance Scheduling: Establish inspection and parts replacement intervals based on duty cycles
- Seal Upgrade Evaluation: If operating conditions intensify, consider alternate designs or materials for improved performance
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Contact HydroMax Seal
Contact HydroMax Seal today for innovative solutions, expert guidance, and over a century of engineering excellence. Your journey to mechanical sealing excellence starts with HydroMax Seal!
E-Mail: sales@hydromaxseal.com
Address: 18511 Beaumont Hwy Building D
Houston, TX
77049









