Drain line valves

Auxiliary feedwater failure not recognized for 8 min Stuck-open relief valve not recognized Loss of coolant not recognized High-pressure safety injection turned off Incorrectly opened drain line valve Steam in primary coolant system not recognized... 

Combustor-shell pressure transducer line drain solenoid valve energized. 

The preferred accumulator is the bladder type as shown in Figure 8-9. Body material should be 300 series stainless steel, in accordance with. ASTM A 240. Either a manual precharge valve or automatic charging system can be used, based primarily on the user s preference. The alternative choice is a direct contact accumulator as seen in Figure 8-10. This accumulator has several problems. The gas used to pressure the top of the oil will eventually be absorbed by the oil, which can lead to drain line foam-... 

If water has to be drained regularly from liquefied flammable gases or other flashing liquids, and if a spring-loaded valve cannot be used, then a remotely operated emergency isolation valve (see Section 7.2.1) should be installed in the drain line. 

Many fires have been prevented or quickly extinguished by remotely operated emergency isolation valves. We cannot install them in the lines leading to all equipment that might leak. However, we can install them in the lines leading to equipment that, experience shows, is particularly liable to leak (for example, very hot or cold pumps or drain lines, as described in Section 7.1.2) or in lines from which, if a leak did occur, a very large quantity of material, say 50 tons or more, would be spilled (for example, the bottoms pumps or reflux pumps on large distillation columns). 

Restrict the size of the second drain valve to M in., and place it at least 1 m from the fust valve. The drain line should be robust and firmly supported. Its end should be located outside tbe shadow of the tank. 

Fit a remotely controlled emergency isolation valve (see Section 7.2.1) in the drain line. 

The drain (blowdown) line on a boiler appeared to be choked. It could not be cleared by rodding (the choke was probably due to scale settling in the base of the boiler), so the maintenance foreman pushed a water hose through the drain valve and turned on the water. The choke cleared immediately, and the head of water left in the boiler pushed the hose out of the drain line and showered the foreman with hot water. Although the boiler had been shut down for 15 hours, the water was still at 80°-90°C and scalded the foreman. 

Clearing the choke should not have been attempted until the temperature of the water was below 60°C, the foreman should have worn protective clothing, and if possible a second valve should have been fitted to the end of the drain line as described in (a) above. The accumulation of scale suggests that the water treatment was not adequate [3]. 

Blowdown from the boiler(s) should always be taken to either a blowdown sump or blowdown vessel before discharging into drains. Both should be adequately sized to give cooling by dilution and be fitted with vent pipes to dissipate pressure safely. The boiler(s) should have independent drain lines for the main manually operated blowdown valve and the drains from a continuous blowdown system. Where more than one boiler is connected to either system the line should be fitted with a check or secondary valve capable of being locked. 

The drum filter consists of a 1 to 5 m diameter cylindrical drum that rotates while remaining partially submerged in an open-feed slurry tank. The drum surface is wrapped around tightly with the filter medium. The drum shell is divided into compartments, and drain lines are connected to the central valve system that permits either vacuum or pres-... 

Plant management wisely insisted on a full review before the plant could be restarted. Equipment inspectors examined each of the five barometric condensers to determine if there were any significant calcium deposits in the drain lines. The barometric condenser drain piping was simplified by routing it directly to the hopper without a valve and without a branch connection. Plant supervision initiated an engineering study to determine if inherently safer vacuum engines should be used as an alternate to barometric systems. 

Turn off steam and close drain. Open valve to 300-liter permeate vessel to charge lines with sterile air to maintain positive pressure while cooling. 

Opening of any valve to a vacuum column is likely to suck in the contents of that line, and possibly materials from other equipment connected to it. These must be thoroughly dried prior to opening the valve. A pressure surge incident resulting from sucking water from a drain line into a vacuum column has been described (4). 

Beware of controlling reboilers by a valve directly on the condensate drain line, and the steam supply pressure is low. 

T0 reduce the quantity of sodium leakage, the drain system was found to require two improvements. One is the addition of a new drain line pipe at the inlet of the secondary pump. The other is the replacement of all drain lines by pipes of larger diameter. In the existing system, each drain line has two drain valves in series to prevent accidental draining by single valve action error. In future so as to assure the draining, each drain line will have double drain valves in parallel. After these improvements, the drain time will be shortened from approximately 50 minutes to 20 minutes. It is estimated that it takes 40 minutes from the occurrence of sodium leakage to finish the drain for the secondary circuit. The modified drain system is shown in Fig.9. 

P IDs show all the process lines in a unit, including valves, material specs, and insulation detail. The P ID may or may not include minor piping such as vent and drain lines and tubing. They provide a pictorial representation of all equipment, instmmentation, and piping in a facility. They are crucial documents in almost all types of safety study and analysis. 

For removing water floating on a chlorinated hydrocarbon bottom layer, two or three drain valves at easily accessible positions should be provided. The valves should be fitted close to the tank sides to avoid the danger of the drain lines freezing up. Product tanks should be fitted with pressure-vacuum valves and with self-closing dip and sample hatches. 

In the air distribution system, all takeoffs should be from the top of the pipe or header. Headers should slope towards their ends and should include terminal drain/blowdown valves. Connection points for hoses should be standardized throughout each plant and should carry prominent reminders to blow out the line before use. 

Figure 20 Principle of a venting filter for in situ integrity tests. The integrity tests are carried out following the water intrusion method 1, primary filter with an 0.22 pm cartridge 2, secondary filter with an 0.22 pm cartridge installed as a backup filter, sterilized independently of the filter 1 3, test liquid reservoir (WFI) with heater 4, inlet valve for test liquid (WFI) 5, pure steam inlet 6, filtered air (5 bar absolute) 7, venting gas (1060 mbar) 8, drain line with valves 9, to water ring pump (WRP) 10, to condenser 11, to chamber 12, sanitary valves 13, temperature sensors.

In case of failure to actuate the electromechanical protection system, reactor shutdown is accomplished by the emergency boron injection system (Fig 7.2.2.). Activation of the system is possible by opening valves in the pipelines connecting the system to the reactor or by rupture of a membrane with simultaneous opening of check valves in the drain line by direct action of the pressure in the reactor. The boron solution is supplied by gravity due to the location of the system tanks above the reactor. 

Liquid hydrocarbons in a coke drum will cause a foamover when hot resid is first switched into the drum. The liquid is condensed when a drum is warmed and should be completely drained by the end of the warm-up period. Before the switch, the drain valve shown in Figure 2-3 is closed. An experienced operator can hear, as he closes this valve, if vapor is blowing freely through it. Also, a low temeprature (450°F to 600°F) at the bottom of the drum indicates that the drain line is plugged. 

First, obtain a sample of the reflux naphtha. Does it contain free water If so, manually drain the water from the reflux drum until hydrocarbons blow out of the drain. About 30 minutes of water-free refluxing should clear up the dirty naphtha. A malfunctioning reflux drum water-naphtha interface level control valve is often the culprit. Perhaps the steam stripping rate has been increased, and the water drain line cannot handle the increased flow. 

Steam purge through separate vent Aggressive use of the warm-up valve Plugged condensate drain line... 

Installation of a control valve directly on the condensate drain line. 

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