330851-02-000-070-10-00-CN Bently Nevada High-Temp Probe

Product Overview

The 330851-02-000-070-10-00-CN is a heavy-duty 3300 XL 25 mm proximity probe specifically engineered for the most demanding steam turbine environments. With its large diameter and rugged construction, it is the primary choice for measuring Differential Expansion (DE) and thrust position on large rotating machinery. This probe serves as a high-performance replacement for legacy 7200-series 25 mm and 35 mm systems. Built for survivability, it operates continuously at 200 °C (392 °F) and features a FluidLoc™ triaxial cable to maintain signal integrity despite high temperatures and moisture ingress.

Technical Configuration

The model number 330851-02-000-070-10-00-CN specifies a hardware build optimized for deep-reach installation requirements:

• Probe Case Type (02): M30x2 threaded stainless steel body.
• Unthreaded Length (000): 0 mm; fully threaded barrel for maximum mounting flexibility.
• Overall Case Length (070): 70 mm case length for extended reach into machine housings.
• Total Length (10): 1.0 meter (3.3 feet) integrated probe cable.
• Armor Option (00): No armor; provides an ultra-lightweight 230 g (8.1 oz) configuration.
• Agency Approval (CN): Country-specific safety certifications for hazardous area compliance.

Technical Specifications

Installation Guide

Proper mechanical installation is vital for the 25 mm system. Use a recommended torque of 68 N•m (50 ft•lb) during mounting, but ensure you do not exceed the maximum rated torque of 163 N•m (120 ft•lb) to prevent thread deformation.

Environmental Considerations

The FluidLoc™ cable is designed to prevent oil or other fluids from wicking through the inside of the cable. However, during installation, maintain a minimum bend radius to protect the triaxial shielding. For hazardous area deployments, ensure the probe is installed with appropriate intrinsically safe zener barriers or galvanic isolators as per Bently Nevada drawing 141092.

Engineering Advantages

The 3300 XL 25 mm system excels in Differential Expansion (DE) monitoring where axial shaft movement exceeds the range of standard probes. Its PEEK tip provides exceptional chemical and thermal resistance, while the AISI 304 stainless steel case ensures structural integrity. This probe is ABS Type Approved for maritime use, meeting 2009 Steel Vessels Rules, making it suitable for both land-based power generation and offshore applications.

Technical FAQs

Q1: What is the benefit of the FluidLoc™ cable?
A1: It prevents moisture and process fluids from leaking through the cable into the Proximitor® housing, which is critical for maintaining signal accuracy in steam-saturated environments.

Q2: Can I use this probe to replace a legacy 7200 series 35 mm probe?
A2: Yes, the 3300 XL 25 mm probe series is specifically designed with case configurations that physically and electrically replace standard 7200 25 mm and 35 mm systems.

Q3: How does temperature affect the hazardous area classification?
A3: The Temperature Classification (T1-T5) depends on the ambient temperature. For example, to maintain a T5 rating, the ambient temperature at the probe must not exceed +40 °C.