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PRESSURE SENSOR ACCESSORIES. 2008-CHEM-83 2008-CHEM-63 2008-CHEM-27 2008-CHEM-129 2008-CHEM-147. SYNOPSIS. Introduction Categories/Kinds of Pressure Sensing Accessories Purpose References. INTRODUCTION. Definition
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PRESSURE SENSOR ACCESSORIES 2008-CHEM-83 2008-CHEM-63 2008-CHEM-27 2008-CHEM-129 2008-CHEM-147
SYNOPSIS • Introduction • Categories/Kinds of Pressure Sensing Accessories • Purpose • References
INTRODUCTION • Definition • To avoid excessive maintenance problems and damage of instruments, special accessories provide a safe and reliable working of instrument as well as the process • Working Principle
CATEGORIES/KINDS OF PRESSURE SENSING ACCESSORIES • Valve Manifolds • Bleed (Vent) Fittings • Pressure Pulsation Damping • Fill Fluid Mechanism • Remote and Chemical Seals
Valve Manifolds Three Valve Manifold A fourth valve called a “bleed” valve used to vent trapped fluid pressure to atmosphere
Two block valves are left open to allow process fluid pressure to reach the transmitter. The equalizing valve is left tightly shut so no fluid can pass between the “high” and “low” pressure sides
Five Valve Manifold • For normal operation and maintenance • Never open while both block valves
Bleed (Vent) Fittings Close-up views of a bleed fitting both assembled (left) and with the plug fully extracted from the fitting (right) Bleed fittings installed in two different ways
Pressure Pulsation Damping An oil-filled pressure gauge Snubber
Fill Fluid Mechanism • Fill the pressure sensor mechanism with a clean liquid (called a fill fluid) • Transfer pressure from the process fluid to the fill fluid
Pressure gauge with a chemical seal diaphragm Chemical Seal Diaphragm Thin metal isolating diaphragm
Electronic PT Remote Seal Capillary tube with coiled metal (“armor”) sheath Close-up view of the sealing diaphragm with corrugated design
Water Traps & Pigtal Siphon Pigtail Siphons Transmitter with Pigtail Siphons
REFERENCES • Singh S.K., “Industrial Instrumentation and Control”, Tata McGraw Hill Publishing Company Limited New Delhi, Edition Ist, Chapter 12, Page 393-397 • Tony R. Kuphaldt, Jan11, 2009, lessons in industrial instrumentation, Creative Commons, page 397-425 • http://iamechatronics.com/notes/general-engineering • Dr. Shahid Naveed, Dr. Ing Naveed Ramzan & Ms. Sana Yousuf 2011, Industrial instrumentation, First Edition, Allied Book company, Pages 77-78