Replacement Seal for JC Carter 50E701 LNG Nozzle: P/N B78705-6 Technical Specifications

1. Overview: The Two Critical Sealing Points of the JC Carter 50E701 Nozzle

The JC Carter 50E701 series nozzle (including models 50E701-1, -2, and -3) is a standard-issue component in LNG (Liquefied Natural Gas) fueling infrastructure worldwide. Its operational reliability and safety depend entirely on two critical cryogenic sealing components.

According to the official service manual's troubleshooting guide, nozzle leakage can be traced to two primary failure points :

1. An external seal that fails while the nozzle is coupled (connected).
2. An internal seal that fails while the nozzle is uncoupled (disconnected).

This article provides a technical identification of both seals and presents a high-performance replacement solution.

2. Diagnosis A: Leakage When Coupled — The Spring Energized Seal (P/N B78705-6)

• Symptom: The nozzle leaks only when coupled to the receptacle and pressurized. Signs include "forceful streams of gas escaping" or "LNG dripping" around the front of the nozzle.
• Part Identification: This fault points directly to the Spring Energized Seal, identified by Part Number P/N B78705-6 (or 93278). This is the "yellow" seal and is the primary component in the official Seal Replacement Kit (P/N B91548-1).
• Function Analysis: This seal (pictured below) utilizes both a metal spring and LNG system pressure to create a tight barrier. It simultaneously seals against two surfaces: the internal "nozzle shroud" and the "receptacle inlet". Failure is often caused by ice buildup or abrasive dirt damaging these sealing surfaces.

3. Diagnosis B: Leakage When Uncoupled — The Poppet Seal Disc (P/N 212536)

• Symptom: The nozzle leaks from its tip when it is disconnected from the receptacle but the dispenser line is still pressurized. This may appear as gas or a "small amount of liquid gas spraying out".
• Part Identification: This fault indicates a failure of the Poppet Seal Disc, identified by Part Number P/N 212536. This is the "white" disc-shaped seal.
• Function Analysis: This disc is an internal component located in the poppet assembly. It is pressed against the "shroud sealing surface" by a spring and system pressure to cut off the flow of LNG when the nozzle is not in use . Failure is often due to contaminants or ice crystals in the LNG supply scratching or abrading the seal's critical edge.

4. XHH Seals Solution: High-Performance Replacements for All 50E701 Models

XHH Seals, an ISO 9001 certified manufacturer and global exporter of high-performance sealing solutions, produces precision replacements for both critical components. Our engineering specifications for these items are as follows:

       External Spring Energized Seal (Replacement for P/N B78705-6):

• Dimensions: 32.8mm x 40mm x 5mm
• Material: Ultra-High Molecular Weight Polyethylene (UPE) Jacket with a metal alloy spring energizer.

       Internal Poppet Seal Disc (Replacement for P/N 212536):

• Dimensions: 5mm x 25mm x 2mm
• Material: Polychlorotrifluoroethylene (PCTFE).

Advanced Materials Engineering: Our material selection is purpose-driven for extreme cryogenic service.

• The UPE jacket (for B78705-6) provides an outstanding low-friction surface, high wear resistance, and maintains toughness and flexibility at LNG temperatures down to -196°C (-320°F).
• The PCTFE disc (for 212536) is a premier cryogenic polymer, renowned for its extremely low gas permeability, dimensional stability, and resistance to brittle failure at cryogenic temperatures.

Guaranteed Compatibility: Our replacement seals are manufactured to be dimensionally and geometrically identical to the OEM parts, ensuring a direct, drop-in fit for all JC Carter 50E701 nozzle variants, including 50E701-1, 50E701-2, and 50E701-3 models.

5. Inquiry & Technical Support

Whether you are experiencing a coupled leak (requiring P/N B78705-6) or an internal poppet leak (requiring P/N 212536), or you are simply looking to secure reliable spares for your B91548-1 maintenance kits, XHH Seals is your direct source.

We supply these components globally, supporting both service depots and field operators.

Contact our engineering department for technical support and quotation.

To ensure accurate identification and fastest response, please provide one or more of the following:

• Required Part Number (P/N)
• Nozzle Model (e.g., JC Carter 50E701-1 / 50E701-2 / 50E701-3)
• Seal Photos (front view + side profile for measurement confirmation)
• Operating Conditions (media, temperature, cycle frequency, etc.)

Email: xhh@xhh-smartech.com

XHH Seals also supplies replacement seals for Macro Technologies CryoMac 3 / 3-50M LNG nozzles.