Cole-Parmer 32718-00 Stainless Steel Differential Pressure Flow Transmitter

Overview

The Cole-Parmer 32718-00 is a precision-engineered differential pressure (DP) flow transmitter designed for reliable, repeatable measurement of low-to-moderate flow rates in laboratory, pilot-scale, and light industrial fluid handling systems. Operating on the principle of laminar or turbulent flow-induced pressure drop across a calibrated restriction—typically an orifice plate or integrated flow body—the device delivers linear analog output proportional to volumetric flow rate. Its robust 316 stainless steel construction ensures long-term stability in chemically aggressive environments, while its compact form factor supports integration into tight spaces within gas chromatography sample loops, solvent delivery manifolds, fermentation feed lines, and analytical reagent dosing systems. Unlike thermal mass or ultrasonic technologies, this DP-based design provides inherent immunity to fluid property variations such as density shifts (within specified viscosity limits), making it especially suitable for applications where consistent calibration traceability and mechanical simplicity are prioritized over dynamic range flexibility.

Key Features

• High-accuracy measurement with ±1.0% full-scale repeatability across eight standard flow ranges (13 mL/min to 10 L/min)
• Fully welded 316 stainless steel housing and compression fittings rated for continuous service up to 150 psi working pressure
• Multiple analog output configurations: isolated 0–5 VDC (models ending in -0x/-2x) or loop-powered 4–20 mA (models ending in -4x/-5x)
• Low-viscosity fluid compatibility (≤10 cSt) including acetone, methanol, IPA, deionized water, nitrogen, argon, and compressed air
• Integrated mounting flanges and standardized 1/8″, 1/4″, or 3/8″ OD tube connections for rapid installation without welding or brazing
• Optional NIST-traceable calibration certificate (P/N 17080-12) supporting ISO/IEC 17025-compliant quality documentation requirements
• Designed for compliance with general-purpose electrical safety standards (UL Recognized Component, CE-marked per EMC Directive 2014/30/EU)

Sample Compatibility & Compliance

This transmitter is validated for use with transparent, non-particulate, low-viscosity fluids (≤10 cSt) that do not precipitate or polymerize within the flow path. It is not recommended for slurries, high-viscosity oils (>10 cSt), steam, or two-phase flows. The wetted materials—316 stainless steel body, Viton® O-rings (standard), and stainless steel sensing diaphragm—are compatible with common organic solvents, aqueous buffers, and inert gases. For regulated environments, the instrument supports audit-ready operation when paired with appropriate power supplies (e.g., 32704-55 or 32704-90) and optional display modules featuring timestamped data logging. While not inherently 21 CFR Part 11 compliant, its analog output architecture allows seamless integration into validated SCADA or DCS platforms where electronic record integrity is managed at the system level.

Software & Data Management

The 32718-00 operates as a stand-alone analog sensor and does not include embedded firmware or onboard software. Signal conditioning and data acquisition occur externally via PLCs, DAQ systems, or dedicated display units. Compatible accessories include the 32706-72 DC-powered 3½-digit LCD flow display (0–5 VDC input, panel-mountable) and the 32704-40 pulse-input flow indicator/totalizer (battery-operated, 8-digit cumulative count). All displays support engineering unit scaling through front-panel programming or external configuration tools. When used with certified calibration reports (P/N 17080-12), the device meets GLP documentation requirements for method validation and routine performance verification. Raw output signals maintain linearity across ambient temperatures from 0°C to 50°C, with thermal zero shift <±0.02% FS/°C.

Applications

• Continuous monitoring of carrier gas flow in GC and HPLC auxiliary systems
• Precise solvent metering in automated synthesis reactors and parallel screening platforms
• Feed rate control in membrane filtration and ultrafiltration test rigs
• Leak detection and purge verification in vacuum manifold assemblies
• Calibration reference for larger flow systems using master-meter methodology (ASTM D3558)
• Environmental chamber humidity control via saturated nitrogen sweep flow regulation

FAQ

Is the 32718-00 suitable for measuring corrosive gases like chlorine or hydrogen sulfide?

No. While the 316 stainless steel body resists many acids and bases, chlorine and H₂S may cause stress corrosion cracking under sustained exposure. Consult Cole-Parmer’s chemical compatibility database before deployment.
Can I use my existing 24 VDC power supply with the 0–5 VDC output models?

Yes—but only if the supply is electrically isolated and ripple-free. Use the 32704-52 cable kit to ensure proper grounding and noise rejection.
Does the device require periodic recalibration?

Per ISO 5167 and manufacturer recommendations, annual verification against a traceable standard is advised for critical applications. NIST-traceable calibration (P/N 17080-12) is available at time of purchase.
What is the maximum allowable upstream/downstream straight-pipe length requirement?

For optimal accuracy, install with ≥10 pipe diameters upstream and ≥5 diameters downstream of any disturbance (elbow, valve, reducer). Refer to ASME MFC-3M guidelines for detailed installation schematics.
Is explosion-proof certification available for this model?

No. The 32718-00 is rated for general-purpose use only and is not certified for Class I Div 1 hazardous locations. Intrinsically safe barriers must be implemented externally if deployed in classified areas.