Determination dropping point

It is difficult to determine exactly the areas of localized pressure reductions inside the pump, although much research has been focused on this field. It is easy, however, to measure the total fluid pressure (static plus dynamic) at some convenient point, such as pump inlet flange, and adjust it in reference to the pump centerline location. By testing, it is possible to determine the point when the pump loses performance appreciably, such as 3% head drop, and to define the NPSH at that point, which is referred to as a required NPSH (NPSHR). The available NPSH (NPSHA) indicates how much suction head... 

Although not widely used, there are other methods to determine the softening point, such as the capillary method, the flow point, the drop point, and the Kofier method. The different methods provide different values of the softening point. In general, the Ring and Ball method provides the highest softening point while the... 

Figure 41.7 enables one to determine dew point at reduced pressure. The left scale shows the dew point at the elevated pressure. Drop from the intersection of this value and the elevated pressure line to the reduced pressure line and then back to the left to read the dew point at the reduced pressure. 

The objective of the titration is to determine the point at which reaction is complete, called the equivalence point. This is reached when the number of moles of OH- added is exactly equal to the number of moles of acetic acid, HC O originally present To determine this point, a single drop of an acid-base indicator such as phenolphthalein is used. It should change color (colorless to pink) at the equivalence point. 

The melting point (determined as slip point or drop point) of the fat. 

The dropping point corresponds to a solid fat content of about 5% (Papalois et al., 1996), and corresponds closely to the softening point determined by the method of Barnicoat (1944) (Timms, 1978 deMan etal., 1983 Papalois et al., 1996). Barnicoat s method was developed for application to milk fat fractions as an alternative to the tedious Wiley melting point technique (Mertens, 1973). In Barnicoat s method, the softening point is taken as the temperature at which a steel ball bearing, initially on the surface of a column of the fat, sinks halfway through the column. In the Wiley method, historically favored in the US, but now an AOCS surplus official method (Firestone, 1998), the melting point is taken as the temperature at which a disc of initially solid fat located at the interface between a layer of water and an (upper) layer of 95% ethanol, becomes spherical. The Barnicoat method is still used in the chocolate industry (Minifie, 1999). 

BSI 1976a. British Standard Methods of Analysis of Fats and Fatty Oils, Part 1. Physical Methods, Section 1.4. Determination of flow and drop points. British Standards Institution, London. 

Melting Point-Mettler Dropping Point (Cc 18-80) determines the temperature at which a sample becomes sufficiently fluid to flow in a specified apparatus the major melting point determination method used by domestic industry. 

Soft base stocks with IV of 90+ are adequately controlled by refractometer (RI or RN) determinations performed within the hydrogenation department. Mettler dropping points and most other melting point analysis have poor reproducibility at this level or are too time consuming. 

Solid fat index (SFI) and drop point were determined for the interesterified and the natural products. The drop point was higher in the interesterified products, whereas the SFI was lower. The amount of solids present in the interesterified products over a range of temperatures (10-40°C) was high enough to meet the requirements of soft-tub margarine (List et al., 1997). 

Several indicators are utilized to determine the point at which the filter space is filled with solids from the bleached oil when the pressure drop across the leaves reaches a predetermined level, when a predetermined decrease in flow rate occurs, or when a calculated load level is reached. Short cycles or premature filter stoppages are usually the result of (i) inadequate body feed (ii) too high flow rate, which can cause the solids to pack (iii) too low flow rate, which can allow the solids to settle and block the flow rate (iv) blinded screens, which reduce the filter surface area or (v) solid load exceeding filter capacity. The perfect circumstance is when the differential pressure is reached, and the flow rate is severely reduced at the same time that the calculated filter capacity is exhausted. Once the filter cycle is complete, the filter cake must be removed and the process repeated all over again (Butterworth, 1978). 

Measuring the flux ratio directly is difficult the shortest-lived delayed neutron emitter group has a half-life of only 0.23 seconds, so determining the point at which the control element is full in is not easy. The computer-based acquisition system is, however, fast enough when sampling at 10 msec intervals, so use of the prompt drop approximation will be used as one method of measurement. 

In case the performance of the CMS is limited by the occurrence of abnormality of the periodic signal causing difficulty to correcdy determine a point where the modulation drops to 10 %, an alternative method using a parallel bar chart shall be applied to verify the compliance of the CMS. In this case, a parallel chart containing black and white lines with a spatial frequency equivalent to the required resolution (MTF) shall be prepared and the distinguishability of the hne in the reproduced image on the CMS monitor shall be verified. 

Notes on Tables Containing Technical Data of Random and Structured Packings as Well as Model Parameters t rFi/t rFi,m for Determining Flooding Point and Pressure Drop... 

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