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Monoflanges and Instrument Manifolds
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Monoflanges and Instrument
Manifolds
Monoflanges and Instrument Manifolds are used as an alternative to multivalve systems. They have been
specifically designed to provide a compact installation for gauge or transmitter
instruments. An application where a monoflange is used is in place of other equipment. For
example, the instance where instead of having one valve and relying on it to close so that
a transmitter can be isolated, two valves are used. A double block and bleed monoflange can be used in place of the two valves. It takes away that need for two valves
and reduces it all into one. That is the monoflange has two valves on it, which are
closed, and a vent that is opened to reduce the pressure between. It has reduced weight
and minimum leak paths providing a higher integrity system. The reduced length of the
installation also reduces the risk of damage through vibration.
Monoflange manifolds can be mounted directly onto vertical or horizontal flanged connections, allowing a gauge to be kept in an upright position. Suitable for both primary isolation (double block and bleed) and instrument (block and bleed) duties a Monoflange provides isolation, venting and instrument mounting in a single compact unit. The designs incorporate safety features that limit vibration and reduce the overall height of a gauge installation.
In order to ensure System Integrity one must not lose sight of the fact that Monoflanges and Instrument Manifolds are subject to Process Conditions eg., pressure and temperature, therefore it is important to purchase high quality units.
Some common questions associated with Monoflanges and Instrument Manifolds
What materials are used and why?What does NPTF thread stand for?|
NPT thread stands for National Pipe Taper. It refers to the thread that tapers
inward to create a better seal. It is recommended that care is taken in
regards to the thread tolerances and only the best quality units are purchased
to achieve this. It is imperative that any manufacturer has demonstrated quality
assurance to a high standard. It is worthwhile ensuring the quality of threads
by gauging at least a proportion of the threads to ensure compliance. Also it is
recommended that thread tolerances and gauging should be specified to a
tolerance better than the requirements of ASME B1.20.1. ICEweb's compression
fittings page has a more detailed explanation of the gauging and tolerance
requirements.
What is an OS&Y valve?
An OS&Y valve is an Outside Screw and Yoke valve. It is a part of the piping
specification. It has a firesafe outside screw construction.
Why is the Molybdenum content of 316SS 2% minimum in an offshore environment?
The molybdenum content is at a minimum 2% to prevent chloride corrosion.
Why is 303 or 304SS not to be used in an offshore environment?
303 or 304SS is not to be used because their molybdenum content is nil and thus the
material is subjected to chloride corrosion.
Is there a maintenance issue when Close Coupled Monoflanges are used? If the Monoflange is installed on a clean, non blocking process then it is not an issue in that access to the tapping point is required very rarely. This is especially so on Fieldbus and HART systems as the transmitter provides a huge amount of diagnostics on-line. The huge advantage of Close Coupling is that many instrument fittings are no longer required, thus eliminating potential leak failure points.
Monoflanges
More
Details on Monoflanges
- From our sponsor Prochem Pipeline products
Monoflange
Specifications and Application data - This
information from Anderson and Greenwood provides some good data.
Installation,
Operation and Maintenance of Monoflanges - Comprehensive
Information from Anderson and Greenwood
Close
Coupled Monoflanges - This design incorporates
all the integrity features of the convention
models, however adds even more safety and cost
saving features. The design eliminates the
requirement for instrument tube, fittings and threaded
connections. Mono Flange Direct, can be provided in
a direct mount version or a interface mounting
plate can be facilitated if required.
Instrumentation
valves, manifolds and enclosures chosen to Enhance Safety of the UK’s Largest
Undeveloped Oil and Gas Reserve Project -
Over 500 Monoflanges and several hundred Largebore
Intellimount units for direct mounting of process instrumentation were specified
to measure liquids and gases for the BP Clair project. The equipment was chosen
to significantly reduce the number of potential leakage points, threaded
connections and impulse lines, in addition to enhancing safety at the new
platform - From Platform Magazine.
Instrument Manifolds
Comprehensive
Catalogue of Instrument Manifold Technical information and specifications - From
Anderson and Greenwood - with 162 pages this is a large 6 Meg download.
Co-Planer
Instrument Manifolds -
Anderson Greenwood MC & MT series Integral Manifolds are designed
specifically for Rosemount Coplanar style transmitters including Model 3051C,
Model 3051P, Model 2024, and the Model 3095 Multivariable transmitters.
Manifold
and Isolation Valve Mounting System for
Direct Mounting DP Transmitters - The system
does not require impulse lines, thereby considerably reducing installation and
maintenance costs.
Titanium instrument manifolds for demanding uses from our sponsor Circor
From our sponsor PROCHEM
PIPELINE PRODUCTS
Information on
Manifolds
Other useful Technical Information
Checking
for Fitting Leaks? - "Leak detective" has the
answer
Great technical information from our sponsors PROCHEM PIPELINE PRODUCTS
Anderson
Greenwood Instrument Valves
Anderson
Greenwood Primary Isolation Valves
Axiswage
Ball Valves
Branch
Fittings
BSP
Fittings
Bu
Tech High pressure components
Buttweld
Fittings
Conversion
Chart
Duplex
Flanges
JIC
Fittings
Gyrolok
Flanges
Gyrolok
Twin Ferrule Tube Fittings
Heat
Exchanger, Condensor & Boiling Tubes
Hygienic
and Tube
Indent
Service
Manual
Sample Systems
NPT
Fittings
O'Brien
Tracepak and O'Brien Analytical
Offshore
Oil and Gas Speciality Valves
Pipe
and Tube
Prochem
Customised Manufacturing
Pyplok
Saflok
Couplers, Y-type Strainer and Swing Check Valves
Selection
of Materials
Socketweld
Fittings
Stainless
Steel Tube
Stainless
Steel Tube, Saddles and Leak Check
Stainless
Steel Tube Chart - Tube weights and working pressures
Swage
and Pipe Nipples and S/S Shim
Teflon
Lined Braided Hoses
Useful
Facts About Stainless Steel
10,000psi
Fittings Specification
The Following links are compliments of Glastonbury
Southern Gage.
Thread
and End Connection Identification Guide - a 56 page document from Swagelok.