UL 51:2002 pdf download – Power-Operated Pumps for Anhydrous Ammonia andLP-Gas.
5.10 When warping ot a casting can affect the tightness of liquid-confining joints, or the necessary fit of parts, the casting shall be stress relieved to reduce to a minimum the possibility of warping.
5.11 A part made of drawn brass or machined from twass rod shall be capable of withstanding, without cracking. the 10-Day Moist Ammonia Air Stress Cradclng Test, Section 19.
6 Bodies. Covers, and Heads
6.1 A pump body assembly shall comply with the requirements specified in the Deformation Test, Section
14: the Leakage Test. Section 15: and the Hydrostatic Strength Test. Section 18.
6.2 Flanges of parts intended to be clamped together shall have sufficient strength to withstand the stresses imposed by tightening of the clamping bolts or cap screws.
6.3 Plugs and other parts, other than cap screws and bolts threaded into noricorrosion-resstant ferrous parts of the pump. shall be of corrosion-resistant metal or be provided with a protective coating if their function is such that they are required to be removed for adjustment, repair. or other care of the pump.
6.4 A plug, cap, or other part threaded into or on the pump body shall engage with at least four full threads.
6.5 A bolt or a screw hole shall not extend through the outer walls of a pump body into a liquid-handling section.
7 Strainers
7.1 A strainer integral with or provided as part of a pump assembly shall conform to the requirements In
7,2 — 7.4 and the applicable requirements for tile Standard for Strainers for Flammable Fluids and Anhydrous Ammonia, UL 331.
7.2 A strainer shall be constructed so that when the screen or filter element is removed for cleaning, all foreign matter (sediment or dirt) is removed without the probability of any of the foreign matter being deposited in the outlet side of the strainer.
7.3 A screen or filter element shall be capable of being removed, cleaned, and readily replaced.
12 PIpe Connections
12,1 Pipe threads shall be in accordance with the Standard for Pipe Threads. General Purpose (Inch),
Exception: Pumps intended for use in installations where pipe fittings incorporate other than NPT type threads shall be permitted to be provided with pipe threads complying with a national pipe thread standard compatible with those fittings. The pipe Thread type shall be identified in accordance with 22.5.
122 Flanges of flange•type pumps shall comply with the respective Amencan National Standard for pipe flanges and flanged fillings covering the material from which they are made.
13 General
13.1 A representative sample of each size and specific design of pump is to be subjected to the tests described in these requirements. Additional samples ot parts constructed of nonmetallic materials are generally required for physical and chemical tests.
13.2 Water or other liquid is to be used in developing the required pressure in a leakage or hydrostatic pressure test. All hydrostatic pressures are to be maintained for at least 10 minutes.
13.3 The investigation of a pump is to be limited to the service conditions for wtiich it is recommended, such as speed, maximum discharge pressure. and liquid to be handled.
14 Deformation Test
14.1 Joints in a pump shall not leak, nor shall there be evidence of damage resulting from the turning elton exerted on pipe-threaded sections when tested as described in 14.2 and 14.3.
14.2 The sample pump used in this test is to be rigidly anchored or otherwise supported. A length of Schedule 80 pipe is to be connected to a female pipe-threaded section of the pump. with the male threads having first been lubricated with SAE No. 10 machine oil. The pipe section is then to be tightened to the torque specified in Table 14.1.