ASME PTC 25:2018 pdf free download

ASME PTC 25:2018 pdf free download.Pressure Relief Devices.
2-4 PARTS OF PRESSURE RELIEF DEVICES
adjusting ring: a ring assembled to the nozzle or guide of a direct spring valve used to control the opening characteristics and/or the reseat pressure.
adjustment screw: a screw used to adjust the set pressure or the reseat pressure ala reclosing pressure relief device. backjlow preventer: a part or feature of a pilot-operated pressure relief valve used to prevent the valve from
opening and tiowing backwards when the pressure at the valve outlet is greater than the pressure at the
valve inlet.
bellows: a flexible. pressure-containing component of a balance direct spring valve used to prevent changes in set pressure when the valve is subjected to a superimposed back pressure or to prevent corrosion between
the disk holder and guide.
blowdown ring: see adjusting ring.
body: a pressure-retaining or pressure-containing member of a pressure relief device that supports the parts of the valve assembly and has provision(s) for connecting to the primary and/or secondary pressure source
bonnet a component of a direct spring valve or of a pilot in a pilot-operated valve that supports the spring. It may or may not be pressure containing.
breaking pin: the load-carrying element of a breaking pin nonreclosing pressure relief device.
breaking pin housing: a pressure-retaining component that supports the breaking pin in a nonreclosing pressure relief device.
buckling pin: the load-carrying element of a buckling device.
cap: a component used to restrict access and/or protect the adjustment screw in a reclosing pressure relief device.
It may or may not be a pressure-containing part.
diaphragm: a flexible metallic, plastic, or elastomer pressure-containing member of a reclosing pressure relief device used to sense pressure or provide opening or
closing force.
disk: a movable component of a pressure relief device that contains the primary pressure when it rests against the nozzle,
disk holder: a movable component in a pressure relief device that contains the disk.
dome: the volume on the side of the unbalanced moving member opposite the nozzle in the main relieving valve of a pilot-operated pressure relief device.
4-5.1 Test Arrangements
The pressure source may be a pump or an accumulator of liquid in combination with high-pressure compressed gas. Measures shall be taken to ensure that pressure pulsations in the system are reduced to a minimum. The flow- meter test arrangement shown in Figure 4-2.3-1 illustrates a recommended arrangement up to and including the test pressure relief device. Figure 4-2.10-3 illustrates a recommended discharge arrangement.
(a) If a flowmeter [para. 4-2.4(a)(1)I is used, the associated measurements shall include, as a minimum, flow- meter differential pressure, device-inlet pressure, and liquid temperature. In this case, the use of a means of determining the volume or weight of the discharge is not a requirement.
NOTE: When conducting tlowmeter tests invoMng a pressure relief device having high inlet pressure and low flow rates, it may be desirable to install the flowmc’tcr downstream of the pressure relief device. Such installations are acceptable provided the installation has been calibrated in accordance with subsection 3-8.
(b) If a ilowmeter is not used, volumetric or gravimetric determination of the pressure relief device discharge over a period of time shall be made. Readings of the device-inlet pressure and liquid temperature shall be made and recorded. Means shall be provided for directing the discharge into and diverting it from the tank used for measuring purposes.
4-5.2 PreLiminary Tests
Preliminary tests may be permitted for testing and adjusting operation of the test apparatus and/or device being tested (see subsection 3-5). Such tests may be necessary to ensure the absence of leaks in the test apparatus and ensure that all gas or air has been vented from the component parts of the system, except those referred to in para. 4-5.1.