New Local Information. This property is not currently for sale or for rent on Trulia. The description and property data below may have been provided by a third party, the homeowner or public records. Fantastic apartment, feels like you are living in a single charming older home! Wonderful location that is close to schools, highways and shopping. Within a few minutes of downtown Foxboro. Beautiful updated baths and kitchen, 1st floor family room plus living and dining room, all with hardwood floors.
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Schedule tours and get more listing information with OJO. Learn more about. An error occurred. Recently Viewed Properties. Collapse Recently Viewed Properties. See This Home. Save This Listing. Share This Link. The A is designed to meet the demands for all water and waste water applications including groundwater, potable water, waste water, sludge and sewage, industry water and salt water.
The A has a field proven and unsurpassed lifetime assured by the fully welded housing, full bore pipe construction, absence of moving parts and wear resistant Easy installation Fitting the A is easy with the flanged design and standard ISO insertion lengths. To further ease the operation, the A can be installed without filters and straighteners.
IP68 Installation in measurement chambers subject to constant flooding is possible with the IP68 rated version. The chambers can even be completely surpassed if the IP68 version is combined with our special subsoil coating, allowing the A to be installed directly in the ground. This magnetic field is generated by a current, flowing through a pair of field coils. A signal converter is used to amplify the signal voltage, filter it and If you require data that is more relevant to your specific application, please contact us or your local sates office.
The manufacturer certifies successful testing of the product by applying the CE mark. The wet calibration validates the performance of the flowmeter under reference conditions against accuracy limits. The accuracy limits of electromagnetic flowmeters are typically the result of the combined effect of linearity, zero point stability and calibration uncertainty.
One debit is that obtained for bottom material in the overhead stream. Another is the debit for overhead material in the bottoms stream and the third is steam or heating fluid cost. A computer manipulates the overhead rate and the reboiler heat input to continuously optimize the sum of these three debits both above and below the fluid capacity limit of the tower from feed rate and composition data.
The desired heat input rate is set as a ratio of the feed rate up to a specified predetermined maximum limit. The computer calculates overhead rate from the following equation:.
Pneumatic or electric signals from the chromatograph and the feed rate recorder located in the fractionator feed line are sent to the com-puter which calculates the overhead rate from the equations set forth above.
This calculated rate is then transmitted by way of a dynamic compensator to the set point of the flow recorder controller FRC which controls overhead draw-ofi rate. The dynamic compensator is used to account for the dynamic response characteristics of the tower so that when the computer takes corrective action after a feed rate or composition disturbance, the corrective action is not only of the correct magnitude but is also supplied at the right time.
Basically, the computer calculates the steady state value of the overhead rate but the dynamic compensator adds transient terms to take care of the dynamic response characteristics of the particular fractionation tower. Heat input to the tower is optimized by establishing a predetermined ratio of steam rate to feed rate and injecting steam into the reboiler in accordance with this ratio by ratioing up to the capacity limit of the tower. The reboiler computer serves to continuously make corrective changes to the flow recorder controller FRC located in the steam inlet line of the reboiler.
When the capacity limit of the tower is exceeded, the reboiler computer automatically alters steam inlet rate to a predetermined optimum value for operation above the vapor capacity limit of the tower.
The factors, a, b, and R, are all factors which are based on experimental data which varies from tower to tower. R determines the magnitude of corrective action for a given change in feed composition. The value of R can be determined by plate to plate calculations or by trial and error methods in the field of the actual frac tionation column.
Factor b determines the point at which the steam can no longer be ratioed to the feed rate because of tower size limitations and the optimum reflux ratio must be altered.
This again can be determined in advance through calculation methods or by trial and error in the field. Factor a is a scale factor indicative of the level of operation of the distillation tower.
Factor a is determined by plotting values of optimum overhead product rate D against feed rate when the tower is operating at the fluid capacity limit 15 of the tower. Factor a is the slope of the line drawn through the data points of D vs.
The values of optimum overhead rate at feed rates at the fluid capacity limit b of the tower are best obtained by running plate to plate calculations at a specific feed rate employing overhead rate.
The overhead rate at which the total operating debit, that is, steam cost, debit for heavy key in the overhead stream, and debit for light key in the bottoms stream is at a minimum value is defined as the optimum overhead rate at a specific feed rate. The present invention makes a significant advance in the art of fractionation tower control. Various computer control techniques, such as that presented in Ser. Patent 3,,, in the name of Eugene C. The disclosure in the above-named application is herein incorporated by reference.
While the above-mentioned computer system serves well in maintaining substantially constant overhead product purity, this result is achieved at the expense of poor quality bottoms product and high utilities cost. This and other advantages of the present invention will become apparent when viewed in the light of the accompanying drawings where:. FIGURE 1 is a schematic representation of a fractionating column with the control system of the present invention. FIGURE 2 is a schematic representation of the pneumatic analog computer network which is used in the control system of the present invention.
Referring now to the drawing and initially to FIG. This column may be of any suitable type which utilizes any conventional liquid-vapor contacting devices known to the art, examples of which are the various types of fractionating trays or packings known to the art.
Numeral 1 designates the feed inlet line to feed surge drum 2. The feed stream which enters line 1 is generally a multicomponent mixture which is to be fractionated in column 60 into a relatively lower boiling stream which is taken off as overhead product, and a relatively higher boiling stream which is taken ofl as bottom product.
The feed stream in line 1 is either liquid or vapor or a mixed liquid-vapor stream. The rate of flow of the feed stream in line 4 from feed surge drum 2 is measured by a rate of flow recorder 5.
Feed flow through line 4 is controlled by valve 6 which is actuated by a level controller 3 on feed surge drum 2. Rate of flow to the fractionator is a function of level in surge drum 2 which is in turn a function of flow into the drum. Therefore, certain deviations in flow rate will occur due to process variations which occur outside of the fractionator system. Level controller 3 or surge drum 2 fiow recorder S and valve 6 are control devices known to the art and can be any conventional equipment capable of performing the functions designated.
The vapor overhead stream is, Withdrawn from the fractionating column 60 by means of line 7. Line 7 connects the upper region of the fractionator 60 with condenser 8. Condenser 8 may be of any suitable type such as, for example, a shell and tube type condenser wherein a liquid coolant is passed through the tubes to condense the vapor stream of line 7, or an air-fin condenser wherein the vapor stream from line 7 passes through the tubes and air is circulated on the outer tube surface as the cooling medium.
By the preferred embodiment, a shell and tube condenser is used and a coolant such as water flows through condenser 8 by means of conduits 9 and Rate of flow controllers can be utilized to control the rate of flow of coolant in line 9; however, their use is not depicted in this figure. The condensate efliuent from condenser 8 passes into line All or a portion of the eflluent can be directed into the reflux line 12 by means of bypass line 13, or can be directed into reflux drum 14 through line Condensed overhead product can be sent to reflux line 12 directly from condenser 8 by means of lines 11 and 13, or from reflux drum 14 by means of line A portion of the eflluent in line 12 passes to column 60 through valve 17 as reflux.
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