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PDFtk (short for PDF Toolkit) is a toolkit for manipulating Portable Document Format (PDF) documents. [ 3 ] [ 4 ] It runs on Linux , Windows and macOS . [ 5 ] It comes in three versions: PDFtk Server ( open-source command-line tool ), PDFtk Free ( freeware ) and PDFtk Pro ( proprietary paid ). [ 2 ]
λ D = The dangerous failure rate of the safety function. TI FC = The full closure interval, i.e. how often the valve must be full closed for testing. TI PST = The partial stroke test interval. The proof test coverage is a measure of how effective the partial stroke test is and the higher the PTC the greater the effect of the test.
A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. [1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure , temperature , and liquid level.
Pressure reducing valve: Valve: Gate valve: Control valve: Manual valve Check valve: Needle valve: Butterfly valve: Diaphragm valve: Ball valve: Check valve: Back draft damper Bag Gas bottle: Globe valve: 3-way valve Piston or reciprocating compressor: Relief valve: Rupture disc: Turboexpander: Centrifugal pump: Reciprocating pump
A relief valve DN25 on cooling water pipe from heat exchanger Schematic diagram of a conventional spring-loaded pressure relief valve. A relief valve or pressure relief valve (PRV) is a type of safety valve used to control or limit the pressure in a system; excessive pressure might otherwise build up and create a process upset, instrument or equipment failure, explosion, or fire.
If the fluid is a liquid, a different type of limiting condition (also known as choked flow) occurs when the venturi effect acting on the liquid flow through the restriction causes a decrease of the liquid pressure beyond the restriction to below that of the liquid's vapor pressure at the prevailing liquid temperature.
This means that they are installed as a component of the completion string and run in during completion. Retrieving the valve, should it malfunction, requires a workover. The full name for this most common type of downhole safety valve is a Tubing Retrievable Surface Controlled Sub-Surface Valve, shortened in completion diagrams to TRSCSSV.
On September 4 at 6:54 p.m. CDT the failed blowout preventer reached the surface of the water and at 9:16 p.m. CDT it was placed in a special container on board the vessel Helix Q4000. [15] The failed blowout preventer was taken to a NASA facility in Louisiana for examination [15] by Det Norske Veritas (DNV).