Catch devices

The Catch device (Balt Extrusion, Montmorency, Erance) is a distally closed, self-expanding nitinol cage that has also been used for thrombectomy with promising results [32]. A comparison between the MERCI and the Catch devices in an animal model has demonstrated superiority of the MERCI Retriever, which resulted in higher rates of overall recanalization (90% vs. 70%), higher chances of recanalization at the first attempt, and a lower rate of thrombus fragmentation/ distal embolization [33]. 

A Utilize positive screen retention A Utilize hopper magnet or other metal-catching device... 

Hosseini-SianaJd, A. Makin, J. Xiao, S. Johnson, A.R. Firoozian, R. Bullough, W.A. Operational Considerations in the Use of an Electro-Rheological Catch Device. Proc. Soc. Fluid Power Transmission and Control, 1st Fluid Power Trans. Control Symp., Beijing, Beijing Inst. Tech. (1991), pp. 591-595... 

Polymers incorporating safety catch device for cleavage of peptide bond... 

Types of Equipment The three most commonly used types of equipment for handling emergency relief device effluents are blowdown drums (also called knockout drums or catch tanks), cyclone vapor-liquid separators, and quench tanks (also called passive scruh-hers). These are described as follows. 

Cyclone Separator with Separate Catch Tank This type of blowdown system, shown in Fig. 26-17 and 26-18, is frequently used in chemical plants where plot pan space is hmited. The cyclone performs the vapor-liquid separation, while the catch tank accumulates the hquid from the cyclone. This arrangement allows location of the cyclone knockout drum close to the reactor so that the length of the relief device discharge hne can be minimized. The cyclone nas internals, vital to its proper operation, which will be discussed in the following sections. 

There are usually several reactors hnked to a single catch tank. To ensure that rupture of a disk on one reac tor does not affect the others, each reactor is fitted with a double-rupture-disk assembly. The use of double rupture disks in this apphcation requires installation of a leak detection device in the space between the two disks, which... 

Gespenstf n. specter, ghost, phantom. Gesperr(e), n. locking device, catch, ratchet, gespieen, p.p. (of speien) spat vomited. Gespinst, n. spun yarn spun goods thread (textile) fabric web cocoon, -faser, /. textile fiber, -pflanze,/. textile plant fiber plant. 

Often a system (a group of vessels not capable of being isolated from each other by block valves, or containing restriction to flow and release of pressure) may need a relief valve set reasonably close, sat +15% to 20% when system is below 1000 psig above, typically use 7% to 15% above as set criteria related to normal operating pressure to catch any pressure upswing. Then this may have a backup valve set higher (but within code) to handle further pressure increase. Or, the second device may be a rupture disk. It is not unusual to have two relief de ices on the same equipment set at different pressures. 

Chapot R. First experience with the Catch, a new device for cerebral thrombectomy. Intervent Neuroradiol 2005 ll(Suppl. 2) 58. 

Should not be fastened with locks other than antipanic catches or other quick releasing devices. 

Horizontal blowdown drum/catch tank This type of drum, shown in Fig. 23-49, combines both the vapor-liquid separation and holdup functions in one vessel. Horizontal arums are commonly used where space is plentiful. The two-phase mixture usually enters at one end, and the vapor exits at the other end. To overcome reentrainment of liquid droplets, due to high inlet velocities, various devices and piping arrangements are used to provide a more uniform distribution of vapor-liquid mixtures into the separator, as shown in Fig. 23-50. For two-phase streams with very high vapor flow rates, inlets may be provided at each end, with the vapor outlet at the center of the drum, thus minimizing vapor velocities at the inlet and aiding vapor-liquid separation. 

FIG. 23-50 Feed distributor devices for horizontal blowdown drums/catch tanks. (Guidelines for Pressure Relief and Effluent Handling Systems, Center for Chemical Process Safely (CCPS) of the American Institute of Chemical Engineers (AlChE) copyright 1988 AlChE and reproduced with permission.). 

Quench pool/catch tank This type of system, as shown in Fig. 23-55, is used to condense, cool, react with, and/or collect a mixture of liquid and vapors discharging from a relief device by passing them through a pool of liquid in a vessel. Feed vapor and liquid (if present) are sparged into the pool of cool liquid, where the vapors are condensed and the liquid is cooled. If the feed materials are miscible with the pool liquid, they mix with and are diluted by the pool liquid if not, the condensate, feed liquid, and pool liquid separate into layers after the emergency relief event is over. The condensed vapors, feed liquid, and quench liquid are contained in the vessel until they are sent to final disposal. 

Equipment Selection Criteria and Guidelines A number of factors should be considered to determine when to select which type ofvapor/gas/solid-liquid separator (blowdown drum or cyclone separator) to handle a multiphase stream from a relief device, and which final control or destruction equipment (emergency flare, emergency scrubber, or quench pool/catch tank) should be selected. These factors include the plot plan space available, the operating limitations of each type, and the physicochemical properties of the stream. 

On one occasion after the polymer catch tank was opened, the waste plastic inside spontaneously caught fire. This also happened when a companion vessel was opened. On two other occasions, waste plastic removed from these vessels spontaneously caught fire after being placed in a dumpster. Investigations did not identify that the fires were likely related to the formation of volatile and flammable substances from thermal decomposition of the plastic. During inspections, the pressure relief device was found to be fouled with solid plastic, which could have rendered it inoperative. The potential consequences of such fouling were not analyzed, and no adequate measures were developed to prevent recurrence. 

Usually it is difficult to justify pressure-resistant construction in the case of extreme operating pressures because of the necessary material strength (JW wall thickness) needed. In individual cases it can also be difficult and labour-intensive to design a vent system for safe venting via pressure relief devices. This can be the case when catch systems are required. A separate document details the conditions and how safe venting from pressure relief systems can be achieved. 

Note Paul himself preferred to call the device lonenkdfig (ion cage) rather than the nowadays accepted term quadmpole ion trap because it does not actively act to catch ions from outside. The acronym QUISTOR derived from quadrupole ion store was also widespread in use. 

Pheromone traps are mechanical devices containing scents that attract a specific insect species. Pheromone traps are available for Japanese beetles and a wide range of other insects. The insects are enticed into the trap by the scent and are unable to get out. These traps attract pests from a considerable distance, but do not immediately catch all the insects they attract. They are best used some distance from the garden to attract the insects away from, not into. 

Simple and inexpensive, these devices are still in place in plating operations all too rarely. The intent of a drain board is to catch drips, preventing them reaching the floor and requiring treatment as waste. Construction can be of any compatible material. Care should be taken to orient the board so as to direct drips to the correct solution (e.g., drips of process solution back to the process bath, not into the following rinse). A small dam at either end is also useful in preventing runoff. 

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