Valves manual

Opening a manual valve. Manual valves which are normally closed to isolate two or more pieces of equipment or process streams can be inadvertently opened, causing the release of a high-pressure stream or resulting in vacuum conditions. Other effects may include the development of critical flows, flashing of liquids, or the generation of a runaway chemical reaction. 

Trickle valves Manual or automatic valves or openings that allow a given quantity of air or other gas to pass from one space to another. 

In one plant, the operating procedures required that valve A should be placed into the "manual closed position." The process worker misinterpreted this information and instead of placing the valve controller in the manual position, he closed the block valve manually and deprived the plant of an essential feed. 

High pressure valves, manual, 13 415 High pressure vessel suppliers, 13 412 High production volume (HPV) chemicals, 24 186... 

The ftinction of the lift lever is to allow manual opening of the valve. Usually, when no extia-lever mechanism is provided, at least 75% of the system s set pressure is required to overcome the spring force by opening the valve manually with a lift lever. While it is required by code, it is judged unsafe to manually open a valve under pressure, especially at higher pressures and higher temperatures, as the person operating the lever would be too close to the valve. 

Control of the hazard could well involve bunding the plant area so that any spills are contained. If the bunds slope to sumps or catch-pits, the surface area available for burning will be reduced. Other important control mechanisms will probably depend on the use of remotely operable shut-off valves on key pipelines (to stop the supply of fuel to any fire, and remotely operated because nobody will want to approach a fire to close valves manually). 

Pneumatic valve Manual valve Pressure regulator valve I I Orifice flange M Retention valve Z Filter... 

Manual On/off valve Manual On-off valve ElectrovaJve with purge Two-way manual valve Flow coatroller... 

If you do not drain the tank and leave about 1 psi on the hydrogen side, then check KOH level, pump more in if needed, and then close the oxygen and hydrogen valves. Manually reconnect the power source and sensor switches for another run. 

In manually operated coke units, the operator must open several block valves manually, open the steam valves, time the amount of steaming, and close the steam valves while opening the water valves. Because each step is manually timed, extra steam and water is consumed and less resid is upgraded into lighter hydrocarbons per day. 

SERVICE VALVE - Manually operated valve mounted on refrigerating systems used for service operation. 

The outside operator checked and found the manual valves at the tank open. The outside operator also saw no indication of flow on the flow meter and made an effort to visually verify that there was no flow. He then began to open and close the valves manually to try to fix the problem. He reported to the control room operator that he heard a clunk that may have cleared an obstruction, and the control room operator tried opening the valve remotely again. Both operators stUl saw no flow on the flow meter. The outside operator at this time got a call to deal with a problem in a different part of the plant and left. He did not make another attempt to visually verify if there was flow. The control room operator left the valve in the closed position. In retrospect, it appears that the tank level at this time was approximately 77 feet. 

AR616 Power Engineers Valve Manual. Power Engineering Magazine. 

Air lock rotary valve Manual or motorised (with constant speed or with speed control). These are generally gas tight and feed sohd powders into a unit operating under pressure or imder vacuum. They can provide fine control action by the speed variation. 

ANSI/ISA-84.00.01-2004 contains several references to the need to provide a manual shutdown backup for the logic solver. The main reference is clause 11.2.8, which states, Manual means (for example, emergency stop push button), independent of the logic solver, shall be provided to actuate the SIS final elements unless otherwise directed by the safety requirement specifications. This clause outlines a specific way a manual shutdown may be implemented, but allows the user to specify other ways to provide a manual shutdown. Manual shutdown can be initiated by the operator using the BPCS, remote or local pushbuttons and switches, or directly with process equipment, e.g., manual closure of valves. Manual shutdown capability should be provided for any SIS where maintenance bypasses are used to support online equipment repair, maintenance, and proof test. 

Nesbitt, B., ed. 2007. Valves Manual International Handbook of Valves and Actuators. Oxford, U.K. Elsevier. Led by a 40-page glossary of definitions and abbreviations in Chapter 1, this work covers valves and actuators of all types and for virtually any application. Most chapters end with a set of useful references. The table of contents contains advertisements from valve and actuator manufacturers and suppliers, and the volume closes with a Buyer s Guide. 

During start-up, before the turbine is synchronized, pressu-re.is controlled by the same dump system eithel automatically or manually. As steam Is passed to the turbine by opening its valve manually the dump valve must start to close to maintain pressure. Auto-control of pressure is switched onto the turbine valve as soon as possible and the dump valve closed manually, which causes the turbine valve to open and Increase its loading. 

The design of a hybrid capillary-flap valve is presented for vapor control in point-of-care microfluidic CDs. The design of the capillary-flap valve is developed after consideration of a wide range of available valves such as membrane valves, flap valves, diaphragm valves, manual valves, and sacrificial valves. The capillary-flap valve is derived from a flap valve for its simplicity in design and low in cost to fabricate, and it complements the existing capillary valves used in microfluidic CDs. 

Self-closing valves are used where failure to close a valve manually might permit flow of oil or gas into areas where a serious fire may result. The types of installation for which self-closing valves should be considered include water and chemical draws, vents, bleeders, drains, level cocks, sample points, and tank truck and barrel filling and emptying systems. 

Per application flow control valve, pressure control valve, temperature control valve, level control valve, on- ofT control valve, manual control valve, emergency shutdown valve. 

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