China
Africa
Explore chapters and articles related to this topic
Determinative Techniques to Measure Organics and Inorganics
Published in Paul R. Loconto, Trace Environmental Quantitative Analysis, 2020
Never remove a two-stage regulator from a gas line with high pressure isolated in the first stage—the sudden release of pressure could rupture diaphragms, ruin diaphragms in downstream regulators, and create gaps in a packed column! Always depressurize a two-stage regulator through the second stage or through the GC. If your system has a single cylinder gas supply or a gas generator, turn off the GC oven first and let the column cool. Then close the first stage (cylinder side) valve on the regulator and leave the shutoff valve downstream from the regulator open. Leaving this value open will allow the gas remaining in the regulator to pass through the regulator. Vent the pressure through the system (be sure the column is at room temperature) through a vent installed in the gas line or a vent on the regulator itself. Finally, close the downstream pressure-control valve and remove the regulator.
The reciprocating piston petrol engine
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
The use of direct-acting sliding followers with a cylinder-head-mounted camshaft demands relatively large-diameter tappets (Figure 1.90). This increase in their base area is dictated by the absence of a multiplying leverage (otherwise provided by rocker arms) in the valve train, so that larger cams have to be used to give the desired amount of valve lift. Since an overhead camshaft is in even closer proximity to the valves than it was the obsolete side valve layout, the tappets must necessarily be both hollow to fit over the valve springs and short in length. For this reason they are aptly termed ‘inverted-bucket tappets’, although they may sometimes be referred to as Ballot-type tappets, having originally been introduced by the French Ballot company for its straight-eight engine in 1919.
Service valves and gauges
Published in A.C. Bryant, Refrigeration Equipment, 2007
Once again, bearing in mind that high pressures are generated whilst a plant is operating, care must be taken not to pollute the atmosphere when gauges are removed. The following procedure will minimize the loss of refrigerant and discharge to atmosphere: Back seat the discharge service valve.Open both shut-off valves on the manifold and allow the pressures to equalize in the gauges.Close high side valve on the manifold and operate the compressor until a zero pressure is indicated on the compound gauge. Close the low side valve on the manifold.Remove the hose from the discharge service valve union, replace the seal cap and tighten.Back seat the suction service valve.Remove the hose from the suction service valve union, replace the seal cap and tighten.Set both service valves to the operating positions (cracked off the back seat).Replace the service valve caps and tighten.Test for leaks at the valve caps and gauge unions (see Chapter 3).
An experimental investigation on the performance of designed closed reactor system on the thermochemical heat storage of magnesium chloride hexahydrate
Published in Experimental Heat Transfer, 2023
A.A. Hawwash, Shinsuke Mori, Hamdy Hassan
In the experimental procedures, 37.6 grams of magnesium chloride hexahydrate have been distributed on the five plates of the heat exchanger before the thermocouples are inserted and fixed inside the salt material for each plate as shown previously in Figure 1c. Four cycles of dehydration and hydration are carried out. The initial condition of the dehydration processes inside the reactor is shown in Table 3. Before the dehydration, the reactor pressure is decreased to achieve vacuum using a vacuum pump and then the vacuum side valve is closed, and the condenser side valve is opened. After that, the ice is covered in the test tube of the condenser to work at the average temperature of 8°C. Then, the thermal path pumps hot water to the heat exchanger at a temperature of 95°C and a mass flow rate of 980 g/min. Figure 3 illustrates the dehydration process for the magnesium chloride hexahydrate. Overall, the highest temperature is at the inlet and the minimum temperature is at the condenser. It is noted that the temperatures of the plates are not the same as there are some material losses in the material after each hydration test because the plates are not designed for the overhydrated salt. Upper plates 4 and 5 have the lowest temperature as they have the maximum losses in the material. In addition, the average dehydration time is about 45 minutes. By repeating the dehydration tests, it is found that the condenser and input temperature are nearly the same. The pressure increases during the dehydration until the equilibrium pressure
Physical properties of mine drainage sediment according to depth in settling ponds
Published in International Journal of Mining, Reclamation and Environment, 2023
Dong-Kil Lee, Joon-Hak Lee, Young-Wook Cheong, Jongmyung Park
The sampling procedure of the sludge in a settling pond with the proposed device is as follows. Initially all valves in the device must be closed. By opening the front valves of both tanks, the sludge can be transferred to both tanks when the side valves are opened. After that, the bottom of the vertical pipe is placed at the target depth relative to the water surface of the settling pond. The side valve of the temporary storage tank is opened and the vacuum pump is operated to store the initially introduced sludge in a temporary storage tank. When the colour and water content of the sludge in the acrylic pipe becomes visually uniform after a certain amount of time has elapsed after the sludge has flowed in, close the side valve of the temporary storage tank and open the side valve of the sample storage tank to transport the sludge to the sample storage tank. When sampling is completed in the sample storage tank, stop the vacuum pump. This sampling procedure is carried out at different depths in the settling pond to obtain samples.
Numerical analysis of the transient pressure damping in a single polymeric pipe with a leak
Published in Urban Water Journal, 2018
B. Brunone, S. Meniconi, C. Capponi
Having in mind that in real pipe systems it may be quite difficult to execute fast maneuvers – unless a proper device is used (e.g. Brunone, Ferrante, and Meniconi 2008; Taghvaei, Beck, and Boxall 2010) or a small-diameter side valve is installed (Stephens et al. 2011) – the effect of the duration of the closing maneuver, , on the transient response has been explored. Moreover the interest for slower maneuvers derives from the fact that for complex systems the damping of the pressure peaks is easier to evaluate with respect to single pressure waves reflected in the first characteristic time as within the time domain reflectometry. Specifically, for cases C and D, as an example, different values of (=) have been considered (). As clearly shown in Figure 9, the pressure signals for cases C and D are almost indistinguishable for all the considered values of .