Check valve failure

Inlet frits prevent check valve failure. 

Reverse 1. Pump failure (with check valve failure)... 

Similarly, in the standard example the check valve failed to close when reverse flow occurred. If this incident turns out to be a single instance of check valve failure, then a radical overhaul of the maintenance and purchasing procedures to do with check valves is hardly justified. The root cause for the reverse flow problem lies elsewhere. 

Deer Park, Texas, USA, Petrochemical Plant, Explosion and Fire Check valve failure in pipeline to compressor causing rupture. 140,000,000 loss. 

August 1987 and 16-20 March, 26-30 July and 7-13 December 1988) have been carried out during the campaigns the containment was isolated and the following parameters recorded differential (external vs internal) pressure, external abs pressure, external air temperature, external humidity, wind velocity and direction, the sun s irradiation and the container s temperature. The radioactive release associated with the ventilation air has been evaluated as very very low (less than 100 Bq per year). Several deteriorated situations were also examined (check valve failure, loss of seals integrity etc) and the results showed that the proposed solution is safe. 

Loss of heat transport circulation - The loss of fluid circulation could occur from pump failure(s), check valve failure to open/shut on a pump switch, loss of the pump controller(s), fluid leak to space, or from a loss of pressure control (accumulator failure). 

Check valve failure Blocked discharge Control valve failure Thermal expansion of liquid Heat exchanger tube rupture Reflux failure and overhead system Loss of reboiler heat Venting of storage tank Failure of individual motor Accidental closure of valve... 

Third, you would. suppose that parallel pumps are identical, that they were manufactured and assembled together. But it is possible that one pump of the pair is the dominant pump and the other is the runt pump. If you start the dominant pump first in the parallel system, and then decide to add the runt pump of the pair, the weaker pump may not be able to open the check valve. The pump operator perceives that the flow meter on the second pump is stuck or broken. This is because the second pump might be dead heading against a closed check valve, maintained that w ay by the dominant pump. If this situation exists, it may re.sult in premature failure of bearings and. seals, leading maintenance and operations personnel thinking that parallel pumps are problematic. 

Check valves are required in the piping system at any point where backflow of gas after a shutdown has the ability to restart the compressor, running it backwards or, for that matter, even in the normal direction. Reverse rotation is totally bad, as many components of the various compressor types are not designed for reverse rotation, and there is some possibility, generally remote, that the compressor could reach a destructive over speed. Forward rotation is bad primarily because the intent was to stop the compressor, and it is now operating out of control. This is a problem, particularly if the shutdown was caused by a compressor failure indication, and the need to stop was to prevent further damage. In this mode, it is unlikely that the compressor can attain an overspeed condition. An application with a high potential for backflow is the parallel operation of two or more compressors. 

Check valves and other reverse-flow prevention devices, if their failure can affect the safety of the plant. 

Laboratory rooms intended for toxic work should be provided with adjacent shower and change facilities. The layout must not require freshly showered personnel to track back through the area that they might have just contaminated. All drains, including those in laboratory floors, should have deep traps and be directed to a toxic sump. Airlocks will help prevent toxic fumes from spreading to non-toxic areas in the event of a failure of a primary containment cabinet. Check valves in the incoming water lines will prevent contamination of potable water supplies when pressure is lost. 

USA often failure of Clow model GMZ check valve Wrong functioning of a check valve, relieved an explosive gas cloud and exploded 4 1980 - 1994 USA,Saudi-Arabia... 

The cell is usually connected to the rest of the system using stainless steel tubing. Both needle and ball valves are available as are check valves that only allow the flow to travel in one direction. The gas is delivered from a cylinder with a pump or compressor in order to provide the required pressures. For safety, two forms of pressure relief are available. Most simply, burst discs can be included to prevent catastrophic system failure due to over pressurization. These are designed... 

At a facility in Pasadena, Texas, a serious fire and explosion occurred on a compressor section involving failure of a check valve, h) During the investigation by regulators, it was disclosed that a similar occurrence had recently taken place. The company was cited for failure to adequately apply lessons learned from previous incidents. 

On June 22, 1997, an explosion and fire destroyed an olefin plant at the Shell Deer Park, Texas chemical complex. Thirty workers received minor injuries and extensive damage resulted to both the plant and adjacent community. The incident was caused by the sudden failure of a pneumatic check valve in a 300-psig gas compressor discharge line that led to a large release of propylene vapor. A few minutes after the release, the gas ignited causing a vapor cloud explosion and flash fire. 

Before the incident, the facility had experienced a power failure that led to the shutdown of an olefins unit. For several hours, a restart had been attempted and the compressor had tripped on high vibration at low speed. This caused the check valve to close, which placed additional stresses on the valve shaft. Failure to execute a smooth planned start-up was a key contributor to the timing of this incident. However, given the design defects inherent in the valve, an ultimate failure was inevitable. 

The primary modes of failure of this type of pump are leakage past the internal check valves or some mishap which leads to a sudden rush of atr into the upper or lower chamber. The first problem impairs the pumping action and is... 

For over 20 years the tank successfully operated with a nitrogen pad to reduce moisture intrusion and a simple hinged breather vent to provide overpressure and vacuum protection. The modification (installed and completed just three days prior to the failure) provided a vent compressor and a new state-of-the-art nearly zero leakage pressure/vacuum device and some unique piping features. See Figure 2—14, which shows impulse block valve No. 4 and the vent check valve No. 2. 

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