Bar maintenance

Bar maintenance—The bottom edge of a bar usually leads into the cut, and so receives the most wear. To balance wear, flip the bar top to bottom after about 20 hours of operation. Always make sure before remounting that the oil hole is clean. 

In proper operation, the tie straps of the chain slide along the bar rails. But as the bar rails in this photo wore down (1), the drive links of the chain started to ride on the bottom of the bar groove, plowing it out. This ruined the chain and burned the bar. The point is With regular bar inspection and maintenance, this problem could have been avoided- 

As the chain slides along the bar rails and the bar begins to wear, a burr can form along the rail edge (2), causing improper chain tracking. Square the rails by draw-filing (3). Support the file on two blocks of wood, each positioned square to the top of the bar. Hold the file as shown in the photo. 

I use a belt sander to clean the sides of the bar and to remove any burrs there 5). Sand evenly over the entire surface. If you don t have a belt sander, use a flat file. 

Also on the bar-maintenance checklist should be a periodic check of bar-groove width, also called bar gauge. With feeler gauges, measure groove width all around the bar (1), and compare this measurement with the known gauge of the bar. 

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Ejector (steam-jet) refrigeration systems are used for similar apph-cations, when chilled water-outlet temperature is relatively high, when relatively cool condensing water and cheap steam at 7 bar are available, and for similar high duties (0.3-5 MW). Even though these systems usually have low first and maintenance costs, there are not many steam-jet systems running. 

A sample point on the suction line of two water pumps became choked, and a maintenance worker was asked to clear it. He was not told how to do so—craftsmen dislike people from other departments telling them how to do their Jobs—but the operators assumed he would use water under pressure or a rod. Instead he used compressed air at a gauge pressure of 115 psi (8 bar), and a pocket of air caused the pumps to lose suction (Figure 1-19). 

A question often asked is, Tf the bar chart is so well suited to maintenance, why change The bar chart is limited in what it can do. If a bar chart is carefully prepared, the planner/scheduler goes through the same thinking process as the CPM planner does. However, the bar chart does not show the interrelationships in the sequence of work nor in the restraints and control the activities have upon each other. 

An allotrope of oxygen, ozone, 03 (8), is formed in the stratosphere by the effect of solar radiation on 02 molecules. Its total abundance in the atmosphere is equivalent to a layer that, at the ordinary conditions of 25°C and 1 bar, would cover the Earth to a thickness of only 3 mm, yet its presence in the stratosphere is vital to the maintenance of life on Earth (see Box 13.3). Ozone can be made in the laboratory by passing an electric discharge through oxygen. It is a blue gas that... 

During maintenance work, simultaneous release of chlorine and acetylene from two plants into a common vent line leading to a flare caused an explosion in the line [10], The violent interaction of liquid chlorine injected into ethane at 80°C/10 bar... 

In order to develop a continuous flux maintenance procedure, the present study examined the transmembrane flux values from the cross-flow filtration module with a filtration media area of 0.0198 m2 (0.213 ft2), a slurry density of approximately 0.69 g/cm3 at 200°C, 17 kg of simulated FT wax with a catalyst loading of 0.26 wt%, and a TMP between 0.68 and 1.72 bar (10-25 psig). The filtration process was run in a recycle mode, whereas clean permeate was added back to the slurry mixture, thus allowing the catalyst concentration to remain approximately constant over the course of the run (given minor adjustments for about 5 ml permeate and slurry samples collected throughout the test). 

The LIMS computer is located on the site, and several terminals may be provided for entry of data from notebooks and instrument readouts and for the retrieval of information. Bar coding for sample tracking and access codes for laboratory personnel are part of the system. Instruments may be interfaced directly with the LIMS computer to allow direct data entry without help from the analyst. The LIMS may also incorporate statistical methods and procedures, including statistical control and control chart maintenance. See Workplace Scene 6.4. 

Overlaying the bars that give the breakdown of cost to the operation (manufacturing, maintenance, retail) is the total energy cost. For central gaseous it includes an important contribution from delivery (diesel fuel) and retail (electricity for on-site compression). For a more extensive discussion, see the text. 

Pressure may cause several changes in enzymes, as well as some changes which are not directly associated with the catalytic process. These changes may include conformational changes and subunit dissociation-association processes. Pressures above 4000 bar may induce conformational changes to such an extent that the enzyme in effect becomes irreversibly denatured. These are dealt with in the next section. In this section we will deal with lower pressures and reversible processes, namely, interactions between subunits in quaternary structures. For most multimeric enzymes, the maintenance of... 

Electronic management systems for maintaining records of inspection, testing, and maintenance are preferred. Bar coding, accompanied with the use of a personal data assistant (PDA) can significantly reduce the amount of time required for recordkeeping. 

Its function is to expand the pressurized solution to separate the "solvent gas" from dissolved extracted components. If a fixed restrictor is used, the mass flow rate of the fluid changes as a function of pressure (density) mass flow can increase by a factor of 25 as pressure is increased from 80 to 400 bar (24). Not only are the pressure and flow coupled, the coupling is via a static conduit whose dimensions are imprecisely controlled during an extraction (partial plugging by particulates and precipitated components, temperature) and from component to component during maintenance replacements. This results in a lack of control in operating parameters (density) and timed sequences (via flow rate and time). A variable restrictor whose dimensions are set and adjusted by an electronic feedback control loop is an alternative solution. 

During maintenance work, simultaneous release of chlorine and acetylene from two plants into a common vent line leading to a flare caused an explosion in the line [10]. The violent interaction of liquid chlorine injected into ethane at 80°C/10 bar becomes very violent if ethylene is also present [11]. The relationship between critical pressure and composition for self-ignition of chlorine—propane mixtures at 300°C was studied, and the tendency is minimal for 60 40 mixtures. Combustion is explosive under some conditions [12]. Precautions to prevent explosions during chlorination of solid paraffin hydrocarbons are detailed [13]. In the continuous chlorination of polyisobutene at below 100°C in absence of air, changes in conditions (increase in chlorine flow, decrease in polymer feed) leading to over-chlorination caused an exotherm to 130°C and ignition [14],... 

At filling stations, the GH2 pressure is usually increased from 200 to 400 bar (3,000-4,500 psig). This compression increases the energy cost of the total operation by about 2% HHV. Naturally, in addition to the operating energy costs, there will also be infrastructure, depreciation, operating, and maintenance costs. 

The procedure was to clear the transfer fine of the waxy material with compressed air supply just before the transfer fine was put in service. On the evening of the accident, an operator connected an air hose to a 90 psig (6 bar) supply to clear the entire 200 meters (600 ft.) of feed line. The operator then walked to the elevated tank to determine if air could be heard rushing out of the tank vent. He heard nothing. The operator spoke to two maintenance employees working near the end of the 20-m3 (700 ft3 or 5,300 gallon) tank and left the area to find his supervisor. Shortly after that, one end of the tank blew off, and the two maintenance mechanics plunged some 40 ft. (12 m) to their deaths. [7]... 

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