Repair, and Maintenance

A pump is a precision instrament and must be treated with as much care as an 

Even under best circumstances some maintenance will be necessary from time to 

Occasionally, the cam needs some lubrication. Follow the instructions. 

For maintenance at or in the pump head it is necessary to work cleanly and with the 

Piston seals become worn and need to be replaced, e.g. once a year (they cannot be repaired). For this purpose the pump head is removed from the pump body then the seals become visible. They are removed with the special tool which was delivered together with the pump. Removing the seals with a screwdriver can scratch the pump head which causes leaking The new seals are brought in place with another special tool. It is necessary to follow the instructions exactly. One must not mix up the two different sides of a seal. A seal which is placed the wrong way must be removed and thrown away it cannot be used once again. The new seals need to be broken in with a low solvent flow and without a column connected. Water should be avoided to break in a new seal. Well suited solvents are isopropanol and methanol. 

A pump is a precision instrument and must be treated with as much care as an analytical balance. All recommendations given in the manual should be followed. Even under best circumstances some maintenance will be necessary from time to time. Also for such operations the manual must be consulted in advance. 

For maintenance at or in the pump head it is necessary to work cleanly and with the appropriate tools. Enough bench space, wipes, cleaning solvent and time is needed and a beaker or bowl should be placed below the pump head 

Blocked or leaky check valves can probably be fixed by sonicating them. Perhaps a number of solvents need to be tried, e.g. water with detergent, tetrahydrofuran or dichloromethane. Some valves fall apart when they are removed from the pump head (beware of loss of the ball ), some can be opened and some are a unit which should not be opened. With the first two designs the ball can be replaced, maybe also the seat, when these parts are scratched and do not seal well any longer. The other types of check valves must be replaced totally if they do not work properly and if a treatment with ultrasonics does not help. 

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Filtration and water-knockout systems are used to clean up the gas before it enters a compressor. Cooling systems are sometimes required to maintain compressor discharge temperatures below 54°C to avoid damage to the pipeline s protective coatings. Automated compressor stations are typically staffed by maintenance and repair personnel eight hours per day, five days per week. Other stations are staffed on a 24-hour basis because personnel must start, stop, and regulate compressors in response to orders from the dispatch office. 

Annual plant maintenance and repair costs average about 6% of the fixed capital iavestment, but should be calculated directly from person—hour per shift data or estimates. The annual cost for suppHes can be taken as 15% of the total maintenance and repair cost. 

Miscellaneous Direct Costs Estimates for the cost of maintenance and repairs, operating supplies, royalties, and patents are best based on company records for similar processes. A rough average value for the annual cost of maintenance is 6 percent of the capital cost of the plant. This percentage can vaiy from 2 to 10 percent, depending on the severity of plant operation. Approximately half of the maintenance costs are for materials and half for labor. Royalty and patents costs are in the order of 1 to 5 percent of the sales price of the product. 

Two types of mechanical-draft towers are in use today the forced-draft and the induced-draft. In the forced-draft tower the fan is mounted at the base, and air is forced in at the bottom and discharged at low velocity through the top. This arrangement has the advantage of locating the ran and drive outside the tower, where it is convenient for inspection, maintenance, and repairs. Since the equipment is out of the hot, humid top area of the tower, the fan is not subjected to corrosive conditions. However, because of the low exit-air velocity, the forced-draft tower is subjected to excessive recirculation of the humid... 

A good solids-hquid separator performs well in service, both initially and over time. It operates rehably day after day, with enough flexibility to accommodate to normal fluctuations in process conditions, and does not require frequent maintenance and repair. Selection of such a separator begins with a preliminary hsting of a number of possible devices, which may solve the problem at hand, and usually ends with the purchase and instaUation of one or more commercially available machines of a specific type, size, and material of construc tion. Rarely is it worthwhile to develop a new land of separator to fill a particular need. 

Comparative costs for conveyor systems can be based only on studies of specific problems. For example, belt-conveyor idlers are available in a range of quahties that may make the best unit cost three times as much as the cheapest. Bearing quahty, steel thickness, and diameter of rolls all affect cost, as does design for easy maintenance and repair. Therefore, it is necessary to make cost comparisons on the basis of a specific study for each conveyor application. 

No hazard of high voltage, simplifying maintenance and repair and permitting collection of flammable dusts... 

Protection with impressed current, with galvanic anodes, and a combination of both processes is used for marine structures and offshore pipelines. Their properties, as well as their advantages and disadvantages, are given in Table 16-1. The protective measures must be optimized for every structure. In the impressed current protection of offshore platforms, for example, the difficulties of maintenance and repair will be of major importance, whereas in harbor installations these problems can be... 

New types of anodes have been developed and tested as shown in Fig. 16-5 to improve the possibility of maintenance and repair. They can be lifted onto a ship and repaired. The connecting cables are also replaceable. In shallow water, the anchorage must be accurately calculated because considerable dynamic stressing can occur in heavy seas. The ocean floor must be suitable for long-term anchorage. No supply ships must anchor in the area around the platform. This requirement alone often prevents the installation of impressed current anodes since the operator does not wish or is not able to restrict himself to these conditions. 

This chapter highlights and summarizes considerations dealing with expander subsystems, materials, manufacture, installation, component design, equipment maintenance and repair that might assist users in developing or evaluating turboexpander specifications. 

The press had been designed with a capacity to deliver 280 kN press force and to work at a production rate of 40 lids per minute. Calculations to determine the distribution of forming loads required indicated that the press capacity was adequate to form the family of steel lids to be produced on the machine. One of the major areas of interest in the design was the con-rod and pin (see Figure 4.66). The first option considered was based on a previous design where the con-rod was manufactured from cast iron with phosphor bronze bearings at the big and small ends. However, weaknesses in this approach necessitated the consideration of other options. The case study presents the analysis of the pin and con-rod using simple probabilistic techniques in an attempt to provide in-service reliable press operation. The way a weak link was introduced to ensure ease of maintenance and repair in the event... 

A major problem is underwater maintenance and repair cost. The average life of the underwater equ ment is about 8 years. 

SAIC Data Base Nudear Plant maintenance and repair records by system and component type selected basic event failure rates and unavailability Data mainly for pumps, valves, diesels, batteries, chargers, and heat exchangers 76. 

NUMBER AND TYPE OF RECORDS Plant maintenance and repair records by... 

The records display a pattern of maintenance and repair that is rarely visible elsewhere and can show less severe equipment damage trends that can lead to total failure. As such, it is possible to determine the total number of failures and failure severity. 

Operating costs, in contrast, are more straightforward to determine because they depend on system efficiency, which, in turn, is related to voltage and current density (the current generated per unit area of electrolyte). Fuel savings are expected since the fuel cell operates more efficiently than a heat engine, and there may be lower maintenance and repair costs because fuel cells have fewer moving parts to wear out. 

In this method each year s savings need to take account of the fact that, as the equipment gets older, the cost of maintenance and repairs is likely to increase. The effect of inflation can also be allowed for in assuming the annual cash flows through the life of the equipment. 

Control of the size and amount of contamination entering the system from any other source is the responsibility of the personnel who service and maintain the equipment. During installation, maintenance, and repair of hydraulic equipment, the retention of cleanliness of the system is of paramount importance for subsequent satisfactory performance. 

An improperly piped system can lead to serious power loss and possible harmful fluid contamination. Therefore, in maintenance and repair of fluid power system lines, the basic design requirements must be kept in mind. Two primary requirements are as follows ... 

Trend data also must be adjusted for maintenance and repair activities. Figure 44.34 illustrates an average trend curve that indicates a sharp rise in vibration levels. It also reflects that, after repair, the levels drop radically. At this point, all baseline and reference values should be reset. If this does not occur, the automatic trending capabilities of the computer-based system do not function properly. 

As the maintenance and repair record indicates the cost of maintenance for the specific item of plant and equipment, a simple system may be used to provide recognition of the different methods by which the work has been carried out, e.g. 

Recourse to the maintenance and repair records or a visual aid enables the engineer to establish if the planned maintenance tasks that are not to be carried out had been maintained either during the previous scheduled visit or, when next due, a planned maintenance visit. If not carried out as programmed, the engineer must ensure that the period over which no planned maintenance is proposed does not exceed any known maintenance/operational requirement. 

Further to the engineer s examination of the returned work dockets, purchase requisitions can be placed for parts, specialist contractors attendance, etc. On completion of all the technical aspects of the process, the information regarding the service carried out on the plant and equipment can then be entered in the maintenance and repair record by the administration. 

Most of these methods allow essential maintenance and repairs to be carried out under workshop conditions without taking the vehicle off the road, providing a spare unit is available. A dominant feature of this market has become the wide availability of spares and service wherever such vehicles may go. 

Perform, as directed, maintenance and repair on nuclear weapons, radar, and inertial fuzes, Permissive Action link Devices, ADM Firing Systems, and Adaptation Kits... 

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