Temperature surroundings

Contact temperature measurement is based on a sensor or a probe, which is in direct contact with the fluid or material. A basic factor to understand is that in using the contact measurement principle, the result of measurement is the temperature of the measurement sensor itself. In unfavorable situations, the sensor temperature is not necessarily close to the fluid or material temperature, which is the point of interest. The reason for this is that the sensor usually has a heat transfer connection with other surrounding temperatures by radiation, conduction, or convection, or a combination of these. As a consequence, heat flow to or from the sensor will influence the sensor temperature. The sensor temperature will stabilize to a level different from the measured medium temperature. The expressions radiation error and conduction error relate to the mode of heat transfer involved. Careful planning of the measurements will assist in avoiding these errors. 

For V-helt drive, the type of helt section and maximum number of belts may be specified, as well as the minimum number —usually 3. B-sections are most common. V-belts are not considered for drives over about 50-60 hp, and a minimum service factor of 1.4 should be specified for continuous duty. Belts should not be used in any conditions where the surrounding temperature is greater than 160°F, with or without fens operating. This is of particular importance in induced draft conditions where belts might be in the exit air stream. 

Assuming the heaters are electric (i.e. have a high surface temperature) and the conditioned space is uniformly surrounded by rooms or the outside then the temperature that should be achieved is the design lift in temperature from the surrounds to room temperature, above whatever the surrounding temperature happens to be on the day of the test. 

Proper chain-drive lubrication increases drive life by dissipating frictional heat generated in the joint area. Heat varies according to the chain speed, horsepower transmitted, center distance, sprocket ratio, drive size, amount of lubricant, and viscosity. It generally ranges from surrounding temperature to 60 to 70°F above the ambient temperature. Normal chain drive temperatures should not exceed 180°F. 

The overall elements that contribute to the limiting of the PV factor are magnitude of pressure, speed of rotation, coefficient of friction of mating materials, lubrication, clearance between bearing and shaft, surrounding temperature, and surface finish, as well as hardness of the mating materials. Bearing wall thickness is also an element in the PV factor since it determines the heat dissipation. 

The thermostatic element component only opens if the surrounding temperature is lowered by the presence of air or other noncondensable gases. These gases can then escape, but entering steam again closes the thermostatic valve. Float thermostatic steam traps are typically used at up to 125 psig. 

For a thermometer to react rapidly to changes in the surrounding temperature, the magnitude of the time constant should be small. This involves a high surface area to liquid mass ratio, a high heat transfer coefficient and a low specific heat capacity for the bulb liquid. With a large time constant, the instrument will respond slowly and may result in a dynamic measurement error. 

The surrounding temperature. The heat could come from nearby components or through internal heat dissipation. If we lower the temperature, the evaporation rate will decrease and extend the life. We will see a little later how this leads to the published temperature multipliers. 

The critical condition is given by point c with Tc being the critical temperature. It should be noted that the critical heat loss rate, Ql2, depends not just on the vessel size but also on the surrounding temperature, T. Hence, the slope and the T intersection of Q in Equation (4.4), as tangent to Qr, will give a different Tc. We shall see that the Arrhenius character of the reaction rate will lead to T0 7X. This is called the autoignition temperature. The mathematical analysis is due to Semenov [3]. 

For a thermometer to react rapidly to changes in the surrounding temperature, the magnitude of the time constant should be small. This involves a high... 

The thermostat is necessary for holding the surrounding temperature of the balance constant it is of special importance for high temperature long-time runs . 

The results depend on the stress type and level, the frequency, the surrounding temperature, and the geometry of the sample. We must note that the temperature of the material rises under the dynamic loading with the usual consequences, such as modulus reduction and ageing. Depending on the thermoplastic, stress can ... 

If the surface temperature does not differ greatly from the surrounding temperature, the highly nonlinear surface boundary condition may be simplified by linearizing the expression for the radiation flux and the Clausius-Clapeyron equation to yield the approximation... 

Reverse osmosis" is the popular name of a general process for the separation of substances in solution. The process consists in letting the solution flow under pressure through an appropriate porous membrane (called the "reverse osmosis membrane") and withdrawing the membrane permeated product generally at atmospheric pressure and surrounding temperature. 

New York City, 2nd-6th May 1999, p.2084-9. 012 STUDY OF SURROUNDING TEMPERATURE EFFECTS ON EXTRUDED FOAM STRUCTURE Lee S T Lee K Sealed Air Corp. 

Foam extrusion experiments are performed to study the effects of surrounding temperature variation on cell structure. LLDPE is used with endothermic chemical blowing agent on a single-screw extruder to exit from a capillary die into environments with different... 

Cover the gel with the rubber clotb, connect to the vacuum pump, and switch on the heating. When the temperature at the position of the gel is the same as that of the surrounding temperature, continue drying for about 30 min and then open the apparatus. If the vacuum is switched off too early, the gel becomes destroyed irreversibly. To prevent this cracking, especially of gels with high... 

An electrical arc with a current intensity of several tens of amperes is created between two electrodes. The surrounding temperature stabilises between 3 000 and 6 000 K (Fig. 15.3). The sample is deposited on one of the electrodes, either in the form of metal fragments or as a powder mixed with graphite. Essentially, it is inserted into a cavity formed at the tip of the electrode. The element is thus vaporised by the arc. 

Assuming the particles to be sufficiently small for the surrounding temperature to be sensibly constant, the following equations describe the variation of temperature. 

In a sedentary state body temperature can be regulated by varying the amount of clothing worn or by adjusting the surrounding temperature. However, these mechanisms are inadequate when strenuous work is undertaken and temperature regulation must then be achieved by the evaporation of sweat from the surface of the skin. 

When a hydrate plug occurs in a pipeline at temperatures above the ice point, the three conditions (sufficient temperature, pressure, and composition) exist for hydrate formation. When hydrates form, flow is blocked so that the plug temperature rapidly decreases to the surroundings temperature at the pipeline pressure. 

To obtain water vapor concentration, output signal intensity by TDLAS is calibrated under a well-controlled environment in variation of relative humidity and surrounding temperature. Figure 10 shows a relationship between water vapor concentration and output signal intensity detected by TDLAS. It is shown that the... 

Isoperibolic means that the surroundings temperature is maintained constant. 

---