Remote controlled valves

The next step is to apply a number of loss control credit factors such as process control (emergency power, cooling, explosion control, emergency shutdown, computer control, inert gas, operating procedures, reactive chemical reviews), material isolation (remote control valves, blowdown, drainage, interlocks) and fire protection (leak detection, buried tanks, fire water supply, sprinkler systems, water curtains, foam, cable protection). The credit factors are combined and appHed to the fire and explosion index value to result in a net index. 

A board-mounted low pressure alarm, set at a positive pressure, and a remote control valve operator, so that repressuring gas can be admitted from the control center, should the automatic system fail to function. 

There are many kinds of control valves. Mechanical valves must be accessible to the operator s hand electrically operated valves permit remote control of flow. For tractors or self-propelled sprayers with enclosed cabs, the remote-controlled valves permit all hoses carrying pesticides to be kept safely outside the cab. 

A. Kocer, A remote controlled valve in hposomes for triggered hposomal release, J. Liposome Res., 2007, 17, 219-225. 

The lights in the hood should be shielded from the hood body in, as a minimum, a vapor-proof enclosure. These can also be selected as explosion-proof units should the usage include substantial amounts of very flammable materials. In fact, if a large portion of the work in the hood is expected to involve very volatile flammable materials, the hood should be designed completely as an explosion-proof unit. In any case, all electrical outlets and switches should be located outside of the hood on the vertical fascia panels. Similarly, utilities should be provided by remotely controlled valves in the side panels operated by handles outside the hood. The connections to the utilities inside the hood must be chemically resistant and should be clearly identifiable as to the utility provided. 

Globe valves are designed for controlling flow and are often fitted with shaped plugs or sleeves to give a flow rate proportional to the extent that the valve is opened they are ideally suited for use as remote-controlled valves. Another feature, often incorporated, is a tight shut-off between two machined faces, but it always requires an up and over feature which obstructs the draining of horizontal lines. The reliance for closure on machined faces limits their use with corrosive liquors or slurries. 

If pressure is redueed, the walls of the vessel will be exposed to less foree and the risk of explosion if the temperature increases will be lower. As a general criterion, API recommends the installation of devices able to reduce the pressure up to approximately 7 bar (relative) or up to half of the design pressure in 15 minutes. If the ground is sloped and the vessel is thermally insulated, this time can be longer. The depressurization can require a remote control valve besides the safety valve. The released material should be eliminated in safe conditions (Shebeko et al., 1996), e g., with a torch. It should also be taken into account that in some eases a strong depressurization ean cause extremely low temperatures, leading to fragile eonditions in the steel. 

Personnel working with fluorine cylinders must be protected by use of a cylinder enclosure or barricade and remote control valves, preferably ones operated by manual extension handles passing through the barricade. The main function of a barricade is to dissipate and prevent the breakthrough of any flame or flow of molten metal, which, in case of equipment failure, could issue from any part of a system containing fluorine under pressure. Barricades of 0.25-inch (6.4-mm) steel plate, brick, or concrete provide satisfactory protection for fluorine in cylinder quantities. Adequate ventilation of enclosed working spaces is essential. Installation in a fume hood is recommended for laboratory use of fluorine cylinders. 

In particular, remotely controlled valves that use pneumatic, hydrauUc, or electrical actuators are subject to actuator failure. In many cases, these... 

A choke manifold, which consists of a series of remotely controlled valves, allows the driller to control and relieve downhole pressures, following a kick . 

Provisions should be made for shielding the radiation sources, in addition to those provisions required during operation, to ensure that personnel can have access to and can occupy the plant control room or the supplementary control points (e.g. the location of the remote shutdown panel) so as to operate and maintain essential equipment without exceeding established dose limits as specified in paras V.27-V.32 of the BSS [2] and paras 4.57-4.65 of Ref. [20]. This includes access to equipment in cases where maintenance or repair may be necessary after an accident. In general, provision should be made to render direct intervention by operators superfluous by instaUing automatic or remote controlled equipment (e.g. remote controlled valves). 

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