Weep holes

In addition, the small motor fan attempts to blow air down over the motor and is no match for the much bigger cooling tower fan drawing air up and around the motor. The small fan in this case is useless- even counterproductive. This application needs a TEAO motor. Cooling tower manufacturers sometimes purchase special motors tailored for their application... special grease, seals, slingers, weep hole locations, epoxy coatings, etc.. Such features make an OEM replacement more desirable than an off the shelf replacement. 

The multiwall vessel was made from an inner shell and 11 layers of wrapping, each drilled with a weep hole. The disintegration was attributed to excessive stresses near a nozzle. These had not been recognized when the vessel was designed. 

The report on the incident states Our reading of the literature led us to believe that as long as the leaking gas could be relieved through the weep holes, it would be safe to operate the equipment. We called a number of knowledgeable people and discussed the safety issue with them. Consensus at the time supported our conclusion. But after the explosion, there was some dispute over... 

A general recommendation [5] is to provide four square inches of weep hole area per 100 ft of net open liquid tray area in the tower. This latter refers to the total of all trays in the tow er. 

Diameter of w eep hole, in. Note that this is the diameter equivalent to area of all weep holes per tray or... 

Stay bolts are also used in many FT boiler designs. Typically, these bolts are provided with a drilled weep hole that leaks if deterioration of the stay bolt occurs due to waterside corrosion, thus providing an early warning to the operator. 

Weep holes are used to drain water from the block cores into the subslab area when surface waterproofing barriers fail. Such a connection between the exterior and interior subslab areas is an obvious channel for radon entry, allowing soil gas to pass from the subslab to the interior of the block wall. Openings from the subslab into the block wall would also make it difficult to apply active SSD at a later date. If the block tops are sealed and the interior of the block wall is sealed, then weep holes would be much less of a problem as radon entry points or as barriers to SSD. 

It has been suggested that it might be possible to retain the weep hole while venting the upper blocks above grade to allow soil gas to escape. This idea would need to be combined with an interior barrier such as paint. In general, weep holes should be avoided and if drainage problems are expected, an exterior drainage should be installed. 

It is recommended that, if weep holes are used, care should be taken that they do not present a radon entry path or a barrier to later SSD. The best approaches appear to be either avoiding weep holes by carefully planning and installing a drainage system that would prevent water from entering the block walls or sealing the block tops and interior of the block wall. 

However, these processes have been found to be dangerous in that expins have occurred for one reason or another. Attempts to eliminate traces of hydrogen in the gas stream (one cause of expins) have led to the use of a Pd catalyst (Ref 28). Other attempts to keep the gaseous mixt below the use of a gas-absorbing solvent (Ref 40). Standard precautions now include sufficient maintenance procedures to eliminate plugged weep holes and corroded piping and reactor shells (Ref 41)... 

Cup nut 2, Threaded collar 3, Male cone 4, Female cone 5, Weep-hole. 

Without a method or mechanism to detect a catastrophic, or even a small release from an inner wall, the use of a secondary outer wall is superfluous. A failure in the inner wall will certainly lead to a failure of the outer wall if the failure goes unnoticed and no action is taken. The secondary wall may delay the release, but release would be inevitable without annular space detection. Typical detection mechanisms include gas analyzers or pressure detectors for vapors, conductivity switches for liquids, or weep holes routed to drain systems that are periodically monitored (Prugh, 1992). A purge gas is sometimes used as a detection medium, to reveal a change in contaminants in the purge gas exhaust (CCPS, 1988b). 

LEAKAGE AND WEEP HOLES. To ensure a minimum of liquid leakage from one tray to another, bubble-cap risers should be fitted firmly or sealed into the trays, and an effective seal is necessary around the tray supports. In large columns, the trays are often made in sections for ease of installation. Each of these sections must be installed carefully to minimize leakage. 

Provision for draining the liquid from a bubble-cap tray when the unit is not in operation is made by the use of weep holes. These holes are usually located near the overflow weir so that any delivery during operation follows approximately the same path as the overflow fluid. The weep holes must be large enough to prevent plugging, but they should not deliver an excessive amount of fluid during operation. A size in the range of to f-in. diameter is usually adequate. 

All stage divider openings must be designed so that the column can be free draining. For this reason, draft tubes are often extended below the opening, or, if they extend above the stage divider, then small weep holes are drilled into the draft tube just above the stage divider. If a disk attached to the shaft is used to minimize back-... 

Penetrations through the trench or pit wall or bottom must be so designed as to prevent penetration or bypass of the membrane. In drains, this is accomplished by the selection of a unit of the Josun type. See Sketch 1 on Drawing 10. Note that this type of drain has a wide collar on the shaft at the surface of the concrete, the thickness of a brick, plus membrane, below the floor level. The membrane is applied over the surface of the floor and under the collar, then an additional thickness of membrane is added over the collar, sandwiching it into the membrane. Above the membrane over the upper face of the collar are weep-holes through the shaft of the drain, so that any liquid that may collect... 

---