Sanitary Absolute Pressure Transmitter with Tri-Clamp Connection for Hygienic Processes

In food, beverage and pharmaceutical production, the instrument is part of the product contact surface - and it must be as cleanable as the tank it monitors. The QWY-324 sanitary absolute pressure transmitter combines a polished 316L flush diaphragm with a Tri-Clamp connection, so there is no dead-leg for product to hide in and no crevice for bacteria to colonize. It measures true absolute pressure against a sealed vacuum reference, which matters more than most hygienic plant engineers realize: fermentation, sterilization and vacuum cooling processes are all defined by absolute pressure, and gauge readings drift with every weather front. One instrument, one gasket, one clamp - and a measurement you can defend in an audit.

Why Do You Need Absolute Pressure Measurement in Hygienic Processes?

Consider what actually defines a hygienic process. Fermentation: yeast activity is governed by the absolute pressure of CO2 above the broth, and the tank is often sealed from atmosphere. Sterilization and autoclaving: the lethality of the cycle depends on absolute steam pressure, not on the difference to the weather outside. Vacuum cooling and freeze drying: the product temperature is set by the absolute vacuum in the chamber. In every one of these, a gauge-referenced transmitter drags the local barometer into your batch. On a stormy day your fermenter looks different from the same fermenter on a clear day - same broth, same biology, different reading. Absolute pressure measurement removes the atmosphere from the equation, giving you a batch-to-batch reference that does not move. And because the QWY-324 is built to hygienic design rules - flush diaphragm, Tri-Clamp mounting, Ra ≤ 0.4 µm finish - adding this measurement does not add a contamination risk.

Working Principle: Flush Diaphragm, Sealed Vacuum Reference, CIP/SIP Safe

The QWY-324 mounts directly in the process line or tank wall through a standard Tri-Clamp ferrule. A flush 316L diaphragm, polished to Ra ≤ 0.4 µm, forms a continuous surface with the pipe wall, so product flows over it without stagnation. Process pressure deflects the diaphragm and is transferred through a short internal fill to a diffused silicon cell that measures it against a sealed vacuum reference - the same principle as our industrial absolute transmitters, in a hygienic package. The electronics convert the signal to 4-20 mA or HART, and the housing is sealed to IP67 so the entire assembly survives CIP and SIP cycles, hose-down and steam. With no vent to atmosphere and no dead-leg, the instrument is simultaneously more accurate and more hygienic than the gauge transmitter it replaces.

Structural Advantages of the QWY-324 Sanitary Absolute Pressure Transmitter

• Tri-Clamp connection (1.5" / 2", DN25-DN50) for tool-free installation and removal
• Flush polished 316L diaphragm with Ra ≤ 0.4 µm surface finish, no dead-leg
• Sealed vacuum reference - no atmospheric vent, no barometric drift, no contamination path
• Wetted parts in 316L/304L with FDA-compliant materials and EPDM/Viton/silicone seals
• Survives CIP and SIP cleaning cycles with media temperature up to 150°C
• 4-20 mA output with HART option for clean-room and control-room integration
• IP67 sealed electronics housing for hose-down and washdown environments
• Compact body that fits existing skids, bioreactors and processing lines

Pain Point Analysis: 4 Working Conditions Where Absolute Reference Wins

Application Case 1: Fermentation Vessel Headspace Control in a Brewery

Application Case 2: Freeze Dryer Vacuum Monitoring in Pharma

Eight Product Advantages of the QWY-324

1. Hygienic Tri-Clamp design with flush diaphragm - no dead-leg, no product hold-up
2. True absolute measurement with sealed vacuum reference for repeatable batches
3. Ra ≤ 0.4 µm polished 316L wetted surfaces, FDA-compliant materials
4. Withstands CIP and SIP cycles up to 150°C media temperature
5. Tool-free installation and removal through standard Tri-Clamp ferrules
6. IP67 housing for hose-down and washdown hygienic areas
7. 4-20 mA with HART option for full integration into validated control systems
8. 24-month warranty with material certificates and calibration documentation

Technical Parameters

Why Choose Our Absolute Pressure Transmitter?

Hygienic instrumentation is about documentation as much as hardware, and Qinwei Instruments supplies both. Every QWY-324 ships with material certificates for the wetted parts, a 3.1-style calibration certificate, and surface finish inspection records - the paperwork your QA team needs for audits and validation. Our factory has supplied sanitary instruments to food, beverage and pharmaceutical projects for over a decade, and our engineers understand CIP/SIP duty, seal material selection and validation documentation. When you choose the QWY-324, you get a hygienic absolute pressure transmitter that is engineered for cleanability, documented for compliance, and backed by a manufacturer that answers when your auditor asks a question.

SEO FAQ

Because the processes themselves are defined by absolute pressure. Fermentation performance depends on the absolute CO2 pressure above the broth; sterilization lethality depends on absolute steam pressure; freeze drying and vacuum cooling depend on true chamber vacuum. A gauge transmitter references the local atmosphere, so its reading changes with the weather - a passing storm front can shift a fermenter reading by several millibar even though nothing changed inside the tank. That makes batch records look inconsistent and forces operators to compensate manually. An absolute transmitter with a sealed vacuum reference reads the same on any day, at any altitude, which means your process data, your validation records and your batch reports all tell the same story.

Yes. The wetted parts are 316L/304L stainless steel with an EPDM, Viton or silicone seal, and the media temperature rating of 150°C covers hot CIP and SIP cycles. The flush diaphragm design means cleaning solution flows across the sensing surface exactly as it flows across the pipe wall, with no dead-leg where soil could survive the cycle. The electronics housing is IP67 sealed, so the transmitter body also tolerates hose-down and the humid atmosphere of a cleaning bay. After each cleaning cycle, the instrument returns to its calibrated zero without adjustment, which we validate as part of the factory test and which our pharma customers confirm during their SIP qualification runs.

Each QWY-324 ships with a calibration certificate with the as-tested values, material certificates for the wetted stainless steel parts, and the surface finish inspection record for the diaphragm. On request we can supply a factory certificate conforming to EN 10204 3.1, additional material traceability, and a certificate of conformity for the seal materials. This documentation package is designed to drop directly into your equipment qualification file. If your site requires specific formats or additional statements, tell us at the quotation stage and we will include them in the documentation set.

EPDM is the standard choice for aqueous, acidic and caustic cleaning media and for most food and beverage products; it withstands hot water and steam well. Viton (FKM) suits fatty, oily and high-temperature media and is widely used in dairy and edible-oil processes. Silicone is chosen for very high temperature duty and for some pharmaceutical applications, but it has lower mechanical strength and is not recommended for steam service. If your product contains solvents or aggressive chemicals, send us the composition and we will confirm the correct seal and wetted material combination. We supply all three seal options so you can match the gasket to the product without changing the transmitter.

The QWY-324 mounts with a standard Tri-Clamp ferrule and clamp - no threading, no welding, no special tools. To remove it for off-line calibration or product changeover, loosen the clamp, slide the transmitter off the ferrule, and cap the line with a standard blind cap. Installation is equally fast: locate the gasket, slide the unit on, and tighten the clamp. Because the diaphragm is flush with the ferrule face, the transmitter can also be calibrated in place using a Tri-Clamp calibration adapter that applies a known pressure to the diaphragm. This tool-free design is one of the reasons hygienic plants standardize on Tri-Clamp instrumentation - it keeps changeover and validation downtime to minutes.

Yes. Mounted at the bottom of a storage tank through a side or bottom ferrule, the QWY-324 measures the hydrostatic pressure of the liquid column, which is proportional to level for a known density. For closed tanks with a pressurized or evacuated headspace, the absolute measurement gives you the combined effect of headspace pressure and liquid head, and we can help you configure the transmitter and the control system to derive true level. The flush diaphragm is ideal for dairy, juice, sauce and cosmetic products where a protruding sensor would trap product and complicate cleaning. Send us the tank height, product density and headspace conditions and we will confirm the range and calibration.