HJ4620/4620P Dual Cartridge Mechanical Seal — Replacement for John Crane Type 4620/4620P
The Formax HJ4620/4620P is a dual cartridge O-ring pusher mechanical seal offered for selected John Crane Type 4620/4620P replacement applications.
It combines inboard and outboard sealing assemblies in a compact cartridge configuration.
Supplier-listed shaft sizes range from 1.000 to 2.750 inches.
Confirm the installation dimensions, pumping-ring configuration, support-fluid requirements and operating conditions before ordering.
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- Product Overview
The HJ4620P is a dual mechanical seal supplied as a cartridge assembly with a sleeve, gland and two sealing stages. The cartridge format brings the components together for handling and installation in compatible pump equipment.
The O-ring pusher design uses dynamic secondary sealing elements to accommodate face wear and limited axial movement. Face materials, elastomers and metal components are selected according to the process fluid and supporting-fluid conditions.
Selection must consider both sealing stages and the associated fluid system. Confirm whether the proposed assembly is intended for unpressurised or pressurised operation before specifying the seal.
- Design Features
| Feature | Description |
|---|---|
| Product Model | Formax HJ4620/4620P |
| Supplier Family Reference | HJ4620 / HJ4620P |
| Seal Arrangement | Dual mechanical seal |
| Construction | Cartridge assembly |
| Seal Technology | O-ring pusher design |
| Sealing Stages | Inboard and outboard assemblies |
| Shaft Sizes | Selected inch sizes from 1.000 to 2.750 inches |
| Pumping-Ring Configuration | Confirm for the quoted assembly |
| Support-Fluid Arrangement | Selected according to seal design and operating duty |
| Replacement Reference | Selected John Crane Type 4620P configurations, subject to verification |
Operating Parameters
| Parameter | HJ4620/4620P Supplier-Stated Specification |
|---|---|
| Seal Chamber Temperature | −50 to +204°C / −58 to approximately +399°F |
| Maximum Seal Chamber Pressure | 20 bar / 2.0 MPa / approximately 290 psi |
| Maximum Sliding Velocity | 23 m/s / approximately 75 ft/s |
| Shaft Size Range | 1.000–2.750 inches; selected sizes listed below |
| Maximum Shaft Speed | Confirm for the selected face diameter and configuration |
| Buffer / Barrier Fluid Pressure | Requires separate confirmation |
| Permissible Differential Pressure | Requires separate confirmation for each sealing stage |
These values are taken from the supplier information and do not define a complete dual-seal operating envelope. Confirm process pressure, support-fluid pressure and permissible differential pressure for the quoted configuration.
Maximum temperature, pressure and sliding velocity must not be assumed to apply simultaneously. The full temperature range does not apply to every elastomer option.
- Material Options
| Component | Supplier-Listed Options |
|---|---|
| Seal Faces | Carbon graphite, reaction-bonded silicon carbide, pressureless-sintered silicon carbide, tungsten carbide |
| Secondary Seals | NBR, FKM, EPDM, FFKM |
| Spring and Metal Components | Stainless steel 304, stainless steel 316, Hastelloy C-series alloy subject to grade confirmation |
Specify the inboard and outboard face pairings separately where required. Material selection must consider compatibility with both the process fluid and the buffer or barrier fluid.
Branded elastomers and specific alloy grades require confirmation in the quotation and supporting documentation.
- Dimensions & Installation
The following table reproduces the supplier’s listed dimensions for selected shaft sizes from 1.000 to 2.750 inches.
The source image labels D1 as millimetres, although the values and stated shaft range indicate inch dimensions. Obtain the supplier’s approved inch drawing before using the table for installation or manufacturing.
- Supplier Dimensional Reference — Inch Units to Be Confirmed
| D1 | D4 Min. | D4 Max. | D26 | L90 | L91 Min. | N | M |
|---|---|---|---|---|---|---|---|
| 1.000 | 1.625 | 1.889 | 4.000 | 2.000 | 1.635 | 2.805 | 0.525 |
| 1.125 | 1.750 | 2.015 | 4.125 | 2.125 | 1.603 | 2.933 | 0.525 |
| 1.250 | 1.875 | 2.294 | 4.250 | 2.125 | 1.603 | 3.213 | 0.525 |
| 1.375 | 2.000 | 2.421 | 4.375 | 2.125 | 1.603 | 3.338 | 0.525 |
| 1.500 | 2.250 | 2.680 | 4.875 | 2.187 | 1.680 | 3.599 | 0.525 |
| 1.625 | 2.375 | 2.812 | 5.000 | 2.187 | 1.680 | 3.766 | 0.562 |
| 1.750 | 2.500 | 2.918 | 5.250 | 2.187 | 1.680 | 3.875 | 0.562 |
| 1.875 | 2.625 | 2.918 | 5.250 | 2.187 | 1.680 | 3.875 | 0.562 |
| 2.000 | 2.750 | 3.015 | 5.500 | 2.375 | 1.711 | 4.000 | 0.562 |
| 2.125 | 2.875 | 3.360 | 5.859 | 2.375 | 1.711 | 4.469 | 0.687 |
| 2.250 | 3.000 | 3.485 | 6.500 | 2.475 | 1.711 | 4.566 | 0.687 |
| 2.375 | 3.125 | 3.610 | 6.500 | 2.528 | 1.711 | 4.719 | 0.687 |
| 2.500 | 3.375 | 3.891 | 6.750 | 2.625 | 1.703 | 5.000 | 0.687 |
| 2.625 | 3.687 | 4.062 | 6.750 | 2.562 | 1.727 | 5.170 | 0.687 |
| 2.750 | 3.687 | 4.062 | 6.750 | 2.562 | 1.727 | 5.170 | 0.687 |
D4 is identified as the seal chamber box-bore range. Interpret D26, L90, L91, N and M using the matching supplier drawing.
Dimensions are catalogue references, not approved manufacturing data. Confirm units, tolerances, gland mounting, axial clearances and connection details before ordering.
- Dual-Seal Operation & Support Fluids
A dual mechanical seal must be selected together with its supporting fluid arrangement.
| Arrangement | Selection Requirement |
|---|---|
| Unpressurised Tandem | Confirm suitability for operation with buffer-fluid pressure below process seal chamber pressure |
| Pressurised Double | Confirm suitability for operation with barrier-fluid pressure above process seal chamber pressure |
| Pumping-Assisted Circulation | Confirm the pumping-ring design, rotation requirements, fluid viscosity and available circulation |
| External Support System | Specify fluid compatibility, cooling duty, pressure control and monitoring requirements |
These arrangements are not automatically available in every replacement assembly. Confirm the proposed operating mode and pressure limits with the supplier.
A pumping ring assists circulation within a suitable system; it does not by itself establish the required barrier-fluid pressure.
- Typical Applications
| Service | Candidate Equipment |
|---|---|
| Chemical Processing | Compatible process and chemical transfer pumps |
| Water and Wastewater | Suitable industrial pump installations |
| Pulp and Paper | Compatible process and circulation duties |
| Power Generation | Suitable auxiliary liquid-service pumps |
| General Industrial Service | Compatible horizontal and vertical pump equipment |
| Mixing Equipment | Selected mixers and agitators following a separate application review |
Suitability depends on the fluid, solids content, lubrication, operating conditions and supporting-fluid system.
Food, beverage, pharmaceutical and other regulated applications require configuration-specific material and compliance documentation.
- John Crane Type 4620P Replacement Compatibility
The Formax HJ4620P is offered for selected John Crane Type 4620P replacement applications. Verify dimensional fit, material compatibility and dual-seal operating requirements before ordering.
The replacement must be checked as a complete assembly. Matching the shaft diameter does not establish compatibility with the gland mounting, seal chamber, piping connections or required support system.
| Compatibility Check | Information Required |
|---|---|
| Existing Seal | Complete model designation, size code and materials |
| Shaft or Sleeve | Diameter, fit and available installation length |
| Seal Chamber | Bore diameter, depth and clearances |
| Gland Mounting | Bolt arrangement, mounting dimensions and available space |
| Cartridge Dimensions | D26, L90, L91, N and M |
| Connections | Port sizes, threads, locations and piping arrangement |
| Pumping Ring | Required configuration and circulation duty |
| Process Conditions | Fluid, pressure, temperature, speed and solids content |
| Support Fluid | Type, pressure, temperature and circulation method |
| Documentation | Existing seal drawing, equipment drawing or measured photographs |
HJ4620 and HJ4620P references require separate configuration checks. Do not assume that both versions have identical pumping features or operating limits.
- Frequently Asked Questions
| Question | Answer |
|---|---|
| Is HJ4620P a single or dual cartridge seal? | It is offered as a dual cartridge O-ring pusher seal. HJ4610 is the related single-cartridge product discussed separately. |
| Is a pumping ring included? | Confirm this in the quotation and assembly drawing. The original Type 4620P includes a pumping ring, but that feature must be verified for the replacement supplied. |
| Can it operate as a tandem or pressurised double seal? | Only when the selected replacement configuration is approved for the intended arrangement and pressure conditions. |
| Does 20 bar apply to the barrier-fluid system? | Not automatically. The supplier describes a seal chamber pressure limit. Support-fluid and differential-pressure limits require separate confirmation. |
| Can I use the original seal’s 3600 rpm limit? | Not automatically. The replacement supplier lists sliding velocity; allowable rpm depends on the selected seal geometry and duty. |
| Is it directly interchangeable with every Type 4620P? | No blanket interchangeability is claimed. Dimensions, materials, pumping features and operating conditions must be checked. |
- Request a Quote
Need a replacement for your John Crane Type 4620P seal? Send the existing seal designation, installation drawing, process conditions and buffer or barrier fluid details to Formax Fluid for review and quotation.
John Crane and Type 4620P are trademarks or product designations of their respective owners. Formax Fluid is an independent supplier and is not affiliated with or endorsed by John Crane.
