Strainers, maintenance

It is neeessary to understand the TDH and it s eomponents in order to make eorreet deeisions when parts of the system are changed, replaced, or modified (valves, heat exchangers, elbows, pipe diameter, probes, filters, strainers, ete.) It s neces.sary to know these TDH values at the moment of specifying the new pump, or to analyze a problem with an existing pump. In order to have proper pump operation with low maintenance over the long haul, the BF P of the pump must be approximately equal to the TDH of the system. 

User maintenance includes operation where not automatic, cleaning of filters and strainers, attention to oil and lubricant levels, belt tensioning, general cleaning, running standby equipment, and verification of control operation. 

Inspection and Preventive Maintenance As with all water-based extinguishing systems, particularly those installed outside, inspection and preventive maintenance are critical to reliable operation. Detection devices are typically inspected, tested, and maintained quarterly or at a frequency deemed more appropriate for a particular location. The water-spray system itself is typically flow-tested at least annually (NFPA 25, 1995). Because of the nozzles small orifice size, scale and corrosion buildup can compromise flow and spray patterns. The use of strainers and the conduct of flow tests will help minimize this potential problem. As stated earlier, preventive maintenance of the overall water supply and distribution systems is an integral part of a reliable system. 

Nozzles are made up of four major parts the nozzle body, the cap, the strainer (screen), and the tip or orifice plate. They may also include a separate spinner plate. Successful spraying depends on the correct selection, assembly, and maintenance of the nozzles. Figure 8.17 illustrates a typical cone pattern nozzel with its parts. 

Pressure Indicator (PI403) is optional. This pressure indicator is used to indicate the fuel oil pressure drop across the strainer/filter (ST402). The pressure drop across the strainer/filter can indicate if cleaning maintenance is necessary. 

Tank, sump, and strainer sludge Operations, maintenance, and closure Metal parts treater... 

An example of an unclean strainer in oxygen valve train needing maintenance. (Courtesy of Air Liquide.)... 

All process traps should have a Strainer in the trap inlet line. An outlet shutoff valve should be provided to permit isolation of the trap for maintenance without having to drain the equipment or shutdown the condensate return header. The trap, strainer, and valves should be arranged to allow access for operation, maintenance, testing, and inspection. Modular hook-ups are recommended. 

Purchaser should note that a good strainer to remove all dust/liquid entrainment from the suction side should be provided for the reciprocating compressor since the clearances are very small. In case non-lubricated type compressor is required, more than one unit should be procured because these machines have more maintenance problems. 

Should be possible to easily erect, repair and dismantle the GL equipment and connected pipes, fittings, etc. Sufficient clearance should be provided on all sides of GL equipment for movement of men, materials and maintenance Raw materials with fluorides, HF, abrasive particles can damage lining Strainers should be provided in inlet lines to the vessel No raw material (solid or liquid) should be added rapidly it should be slowly introduced without hitting the GL shaft or agitator... 

Depending upon the particular conditions of installation, such items as oil strainers, air filters, screens, etc. will accumulate foreign matter. All filters, screens, and strainers should be periodically cleaned to avoid any obstruction or malfunction. A smoke condition in the burner can be caused by an obstructed air inlet to the blower or by an obstructed compressor air filter just as well as by excess fuel input. A reduction in oil flow can be caused by a dirty oil strainer. A regular maintenance program should be set up according to the particular installation conditions to prevent any accumulation of foreign material. 

All lines to a compressor that must be removed for maintenance of the compressor or strainer removal must have a set of flanges in the line in addition to the set at the compressor nozzle. Exhibit 4-49 shows one line with a built-in extra set of flanges at the shut-off valve and another line for which flanges must be added because there are no other flanges near the compressor case. 

Poor maintenance of lubrication-system components, such as filters and strainers, typically causes premature failure. Such maintenance is crucial to reciprocating compressors because they rely on the lubrication system to provide a uniform oil film between closely fitting parts (e.g., piston rings and the cylinder wall). Partial or complete failure of the lube system results in catastrophic failure of the compressor. 

Valve failure during maintenance on pump strainer inVisbreaker caused oil spin that auto-ignited. 

Tanporary strainers are intended for short periods of application, such as being fitted during the run-in period of a new system, or when restarting a pipeline system after shut-down and maintenance. They are intended to remove coarse debris particles present in the systan. After a suitable period of use, they are removed (and can be cleaned and stored for future use). 

The second stage of separation offers several alternatives thick media pressure filter, pleated paper roll filter or cartridge, strainer, or hydrocyclone. Only the last, the hydrocyclone, does not reqnire preventative maintenance or utilize consumables, and so seems the best choice, especially from the point of view of flexibility. The hydrocyclone is also extremely durable, due to the abrasive resistant nature of the normal material of construction, namely polyurethane, together with its high impact resistance, frequently necessary in a workshop environment. 

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