Industrial separation vessels are high-tech devices whose main task is to protect sensitive components of measuring instruments (including pressure transmitters, pressure gauges, etc.) from the negative effects of a wide range of aggressive, highly viscous, contaminated, and/or high-temperature operating media in double-walled tanks.
In the AO NPK VIP catalog, the following types of separation vessels are presented:
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Nozzle
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Flanged
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Diaphragm
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Tubular
Applications
Separation vessels are used when the measured medium may:
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Cause corrosion of the sensitive element of the instrument
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Clog internal cavities with particles or due to high viscosity
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Crystallize or change plasticity
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Exert high temperature influence
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Fail to meet hygienic requirements in the food industry
Principle of Operation
The principle of operation of any type of separation vessel consists in transmitting pressure from the problematic medium to a neutral (measuring) liquid through the separation element — a diaphragm or a bellows (e.g., PTFE).
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The pressure of the measured medium acts on the separation element.
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The element deforms, displacing the measuring liquid from the vessel into the instrument.
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The instrument registers the pressure value through transmission via the neutral liquid.
The space between the diaphragm and the pressure gauge is completely filled with a special liquid that transmits pressure. The diaphragm prevents the separation liquid from direct contact with the measured medium.
Main Types of Separation Vessels
1. Nozzle Separation Vessels
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Connection: threaded (metric, BSP, or NPT)
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Design: detachable, with internal diaphragm
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Features: replacement of individual parts possible
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Operating pressure range: –1 to 600 kgf/cm² (Type B – up to 200, Type W – up to 250, Type BW – up to 600)
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Temperature range: –90 °C … +400 °C
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Accuracy: within the reference accuracy class of the instrument
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Applications: contaminated, liquid, gaseous aggressive, and highly viscous media (including solidifying hydrocarbons, e.g., fuel oil)
2. Flanged Separation Vessels
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Connection: flanged, per GOST, DIN, or ANSI standards
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Design: detachable, with external or internal diaphragm placement
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Instrument connection: threaded M20×1.5
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Operating pressure range: –1 to 250 kgf/cm²
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Materials: housing – stainless steel; diaphragm – PTFE; flange – carbon or molybdenum steel
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Applications: pulp and paper industry, food industry (special options available), pharmaceutical industry
3. Diaphragm Separation Vessels
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Connection: various, including capillary
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Design: detachable or welded
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Materials: diaphragm – stainless steel, tantalum, titanium, Hastelloy, nickel alloys; housing – stainless or chromium-nickel steel
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Operating pressure range: vacuum (–1 kgf/cm²) to 600 kgf/cm² (60 MPa), depending on model
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Temperature range: –50 °C … +200 °C (some models up to +350 °C)
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Accuracy: ±0.5% (compensated by instrument calibration)
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Applications: universal use in industrial systems, ensuring reliable pressure measurements in extreme conditions
4. Tubular Separation Vessels
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Connection: radial or axial instrument/capillary connection; optional flange mount
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Design: welded, with external diaphragm placement on the tube
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Tube length: 50 mm (standard), optionally 100 / 150 / 200 mm
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Operating pressure range: –1 to 250 bar
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Minimum Upper Range Limit (URL): 0.05 kgf/cm²
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Temperature range: –90 °C … +400 °C
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Applications: thick-walled tanks, insulated tank walls, flow measurement, aggressive/viscous media
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Features: diaphragm flush with tank wall prevents clogging, ensures accurate measurement in double-walled tanks; filled under vacuum
Industries of Application
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Oil industry – for petroleum products
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Chemical industry – for aggressive media
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Food industry – with hygienic requirements
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Pharmaceutical industry – for sterile production
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Energy – for steam and hot media
How to Buy Separation Vessels from AO NPK VIP
To purchase a separation vessel for pressure transmitters or gauges, request wholesale/retail prices, and calculate delivery (across all cities in Russia), please send an inquiry form to zakaz@npkvip.ru.
The price of equipment depends on the version and other parameters. For consultation on selection of AO NPK VIP measuring instruments, please call +7 (343) 302-03-53.