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Publication numberUS3324009 A
Publication typeGrant
Publication dateJun 6, 1967
Filing dateNov 27, 1963
Priority dateNov 27, 1963
Publication numberUS 3324009 A, US 3324009A, US-A-3324009, US3324009 A, US3324009A
InventorsJoseph W Griffith, Weiss Gunther
Original AssigneeElectro Glass Lab Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Mercury distillation apparatus with electric heat control
US 3324009 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

June 6, 1967 MERCURY DISTILLATION APPARATUS WITH ELECTRIC HEAT CONTROL Filed Nov. 27, 1963 T VACUUM J. W. GRIFFITH ETAL 2 Sheets-Sheet 1 24 la 8 32" I92; 2081' a/x x ea a Joseph WGri f F1 H1 Guni'her Weiss INVENTORS BY @QQQM r EYN b Q8 .1. 9% .3. 3w 3 H G 2 @MN fi N/Z vww 4 fi L www QM 3N J. w. GRIFFITH ETAL 3 2 Sheets-Sheet 2 INVENTORS Joseph WGr' ffjfh Gunf'her {4/6158 Hgen 1' June 6, 1967 MERCURY DISTILLATION APPARATUS WITH ELECTRIC HEAT CONTROL Filed Nov. 27 1963 3,324,009 MERCURY DISTILLATION APPARATUS WITH ELECTRIC HEAT CONTROL Joseph W. Griflith, Portland, and Gunther Weiss, Beaverton, reg., assignors to Electra Glass Laboratories, Inc., Beaverton, 0reg., a corporation of Oregon Filed Nov. 27, 1963, Ser. No. 326,529 6 Claims. (Cl. 202173) This invention relates to apparatus for distilling mercury, and more particularly to automatic apparatus for the continuous multiple distillation of mercury.

Apparatus provided heretofore for the continuous distillation of mercury are characterized by being bulky assemblies which utilize an excessive amount of space, which are difficult and time consuming to clean, and which utilize complex and costly control equipment while still providing only minimum control.

Accordingly, it is the principal object of the present invention to provide mercury distillation apparatus in the form of a compact assembly of a minimum of components, utilizing a minimum of space, while providing for the eflicient production of mercury of high purity.

Another important object of this invention is the provision of mercury distillation apparatus which is capable of being cleaned with speed and facility, without disassembly.

Still another important object of the present invention is the provision of mercury distillation apparatus in which operation is controlled automatically in accordance with predetermined conditions of coolant circulation and mercury levels.

A further important object of the present invention is the provision of mercury distillation apparatus which includes simplified automatic feed control means for maintaining precise mercury feed to the distillation component.

A still further important object of this invention is to provide mercury distillation apparatus which is of simplified construction for economical manufacture and requires a minimum of maintenance.

The foregoing and other objects and advantages of the present invention will appear from the following detailed description, taken in connection with the accompanying drawings in which:

FIG. 1 is a fragmentary schematic view in side elevation of mercury distillation apparatus embodying the features of the present invention;

FIG. 2 is a fragmentary sectional view taken along the line 2--2 in FIG. 1; and

FIG. 3 is a schematic electrical diagram of a control circuit for the distillation apparatus of the present invention.

Referring primarily to FIG. 1 of the drawings, the preferred embodiment of the apparatus illustrated includes a supply reservoir from which dirty mercury to be distilled is fed by gravity to an automatically controlled constant level feed device 12. From this device the mercury is fed to the first of three evacuated boilers 14, 16 and 18, respectively. The first boiler communicates with a condenser 14' having a distillate outlet tube 20 communicating through the vapor trap 22 with the second boiler 16. The second boiler communicates with a condenser 16' Whose distillate outlet tube 24 communicates through the vapor trap 26 to the third boiler 18. The third boiler communicates with the condenser 18' whose distillate outlet tube 28 communicates through the vapor trap 30 with the upper end of a distillate receiver flask 32.

The receiver flask and the condensers are connected at their upper ends to a source of vacuum (not shown), and the boilers are connected at their lower ends through valves to a drain tube, as explained more fully hereinafter.

Considering the foregoing in greater detail, the supply United States Patent 0 3,324,009- Patented June 6, 1967 reservoir 10 comprises a tank 34 provided with an inlet opening 36 (FIG. 3) for introducing dirty mercury to be distilled. The tank also is provided with an outlet tube 38 adjacent its bottom for communication with the feed device 12. The outlet tube preferably is flexible and is arranged for detachment from the supply reservoir, for purposes described more fully hereinafter.

The constant level feed device 12 comprises a housing having an upstanding outer wall 40, a bottom wall 42 and a top wall 44. An inner wall 46 is spaced inwardly from the outer wall and is joined at its upper end to the top wall. The inner wall extends downward and terminates a spaced distance above the bottom wall. Thus, there is provided a feed reservoir 48 in the space between the bottom wall and the lower end of the inner wall, and this reservoir communicates with the annular chamber 50 formed between the outer wall and the inner wall. An outlet opening 52 communicates said annular chamber with the atmosphere.

The inner wall 46 defines an inlet chamber 54 which communicates at the lower open end of the inner wall with the feed reservoir 48. An outlet opening 56 communicates this inlet chamber with the atmosphere. The inlet chamber also communicates at its upper end with the lower end of the outlet tube 38 from the lower end of the supply reservorr.

The lower end of the outlet tube 38 is provided with a valve seat 58 which conforms to the shape of the valve head 60 provided at the upper end of the valve member 62. The valve member is received freely within the inlet chamber 54 for vertical movement within the inner wall 46 and its lower end projects into the feed reservoir 48. The valve member is made of a material which is of less density than the mercury. In the preferred embodiment, the valve member is made of a length of hollow glass tubing closed at its bottom end and sealed at its upper end by the valve head 60.

In the operation of the constant level feed device 12, mercury flows by gravity from the supply reservoir 10 downward through the outlet tube 38 and inlet chamber 54 into the feed reservoir 48. As the level of mercury in the feed reservoir rises, the valve member 62 also rises with it until the mercury reaches a level 64 at which the valve head 60 seals against the valve seat 58 and thus shuts off further flow of mercury from the supply reservorr.

An outfeed tube 66 communicates at its bottom end with the bottom of the feed reservoir 48 and extends upwardly therefrom for communication at its upper end with the first boiler 14 intermediate the top and bottom ends of the latter.

The position of the constant level feed device 12, and hence the length of the outfeed tube 66, are so chosen that the differential pressure between atmosphere and the sub-atmospheric pressure within the boiler, causes the mercury in the outfeed tube to rise to the point where it just feeds into the boiler. Thus, it will be understood that the position of the constant level feed device will vary in accordance with the barometic pressure at the site of operation of the distillation apparatus. In this regard the constant level feed device may be mounted for vertical adjustment on a support and the tubes 38 and 66 may be provided as flexible tubings. Alternatively, the correct position of the constant level feed device may be ascertained for a fixed installation, and the tubes 38 and 66 then cut to proper size, if glass or other rigid tubing is employed.

Each of the three boilers illustrated comprises a hollow housing having an upstanding peripheral wall 68 and an annular bottom wall 70 joined thereto. The bottom wall slopes to one side of the boiler, and a drain conduit 72 communicates through the lowermost portion of said bottom wall with the interior of the boiler. A shut-off valve 74 in each drain conduit controls communication of the latter with a common drain tube 76.

Joined to the inner edge of the annular bottom wall 70 and extending upwardly therefrom into the boiler is an inner peripheral wall 78 which is closed at its upper end by the top wall 80. Thus, there is formed a downwardly open wall 82 centrally of each boiler for the removable reception of an electrical heater element, for heating mercury therein to its boiling point.

The upper end of each boiler housing wall 68 is open and is joined to the lower end of an elongated, upwardly extending condensing tube 84. The upper end of the tube is open from communication with the condensing chamber in which the tube is contained. In the preferred embodiment best illustrated in FIG. 2, the upper end of the tube is formed in the shape of a bowl 86 which is open at its upper end and is provided with a plurality of circumferentially spaced lateral openings 88 adjacent the upper end. A mantle 90 is mounted over this open upper end of the tube, being secured thereto by welding or otherwise joining the circumferentially spaced downwardly projecting fingers 92 to the upper edge of the bowl. The mantle diverges downward in outwardly spaced relation to the bowl, to direct mercury vapors from the upper end of the tube downward toward the bottom end of the condensing chamber, i.e. in the direction opposite the source of vacuum.

Each of the condensers is formed by a hollow tube 94 defining a condensing chamber 96 therein. Each tube 94 is sealed at its bottom end to the lower, flared end of the associated condensing tube 84. In the preferred embodiment illustrated, this joining seal is provided in such manner that the bottom end of the condensing chamber slopes downward to the side which communicates with the distillate outlet tube. This arrangement insures complete removal of mercury distillate from the condensing chambers.

The upper end of each condensing chamber tube is connected to a common source of vacuum. In the preferred embodiment illustrated, the upper end of each tube communicates with a hollow bowl 98. An inlet conduit 100 from the vacuum source projects into the bowl of the first condenser assembly 14' and terminates in an upwardly directed opening 102. A connecting conduit 106 terminates at one end in said bowl in a downwardly directed opening 108 and terminates at its opposite end within the bowl of the second condensing unit 16 in an upwardly directed opening 110. A second connecting conduit 112 terminates within said bowl in a downwardly directed opening 114 and at its opposite end in an upwardly directed opening 116 within the bowl of the third condensing unit 18. The conduit 120 from the receiver flask 32 terminates within said bowl in a downwardly directed opening 122.

It is by virtue of the oppositely directed openings within the bowls 98 associated with the condensing units, that mercury vapor is prevented from being drawn into the vacuum supply. In this regard the connecting conduits 106 and 108 are arranged to slope downward toward the preceding condensing unit so that any mercury vapor which might enter these conduits will condense and be returned to the next preceding condensing unit.

The tube 94 defining each condensing chamber 96 is enclosed in an outwardly spaced wall 124 which is sealed to the tube at its top and bottom ends. There is thus formed between the tube and outer wall an annular space 126 for the circulation of coolant liquid. In this regard a coolant inlet tube 128 communicates with the bottom end of the space 126 associated with the first condensing unit 14', the connecting tube 130' communicates the upper end of said space with the lower end of the space associated with the second condensing unit 16, the connecting tube 132 communicates the upper end of said space with the lower end of the space associated with the third condensing unit 18, and the outlet tube 134 communicates the upper end of said space with a drain.

Since maximum vaporization of mercury occurs in the first boiler 14, additional condensing surface preferably is provided in the associated condensing unit 14'. In the embodiment illustrated, this additional condensing surface is provided by the multiple hollow bowls 136 positioned within the condensing chamber 96 above the condensing tube mantle and communicating at its opposite ends with the coolant space 126.

Interposed between the coolant inlet tube 128 and the source of coolant, such as water, is an electric switch 138 (FIG. 3) which is actuated to closed position when coolant is being circulated through the condensing units. The purpose of this switch is explained in detail hereinafter, and it may be of any conventional type such as the well known fluid pressure operated diaphragm actuated switch illustrated schematically in FIG. 1.

Automatic control of operation of the apparatus is achieved by utilizing the electrical conductivity of mercury in the various units of the assembly, in association with the electrical circuitry illustrated in FIG. 3, as follows:

In preparation for operation of the apparatus, the terminals L L and L are connected to a suitable source of electric supply. In this regard it is to be understood that the terminal L represents a common ground to which all of the ground connections indicated in FIG. 3 are connected. When coolant water is admitted from a tap to flow through the spaces 126 of the condensing units, the electric switch 138 is closed, thereby energizing relay 140 and effecting transfer of its associated contact from the position indicated and completing the electric circuit of the primary winding of the transformer 142 associated with the rectifier power supply 144.

Mercury to be distilled then is filled into the supply reservoir 10. When the level of mercury rises to the level of the electrical contact 146 positioned adjacent the bottom of the reservoir (and insulated electrically therefrom), the electric circuit of the relay 148 is completed from the power supply 144, through said relay and contact 146, thence through the mercury to the common ground of the grounded housing 34 of the supply reservoir. Contact A of relay 148 thereupon transfers from the closed position illustrated, to open the electric circuit of the neon lamp 150 which previously was energized to indicate that the supply reservoir was empty.

When the level of mercury in the supply reservoir reaches the electrical contact 152 positioned adjacent the top of the reservoir, the electric circuit of the neon lamp 154 is completed, to give visible indication that the supply reservoir is full.

Mercury to be distilled flows by gravity from the supply reservoir through the tube 38 and inlet chamber 54 into the constant level feed reservoir 48 until it reaches the level 64 at which the valve member 62 elevates the valve head 60 into sealing engegement with the seat 58. The supply of mercury from the reservoir 10 thus is shut oif.

With the source of vacuum connected to the conduit 100, the assembly of boilers, condensers, and receiving flask are evacuated (the shut off valves 74 being closed). Accordingly, mercury from the reservoir 48 is forced upward through the outfeed tube 66 and into the first boiler 14. As the level 64 of mercury in the feed reservoir 48 drops slightly, for example about two millimeters, the valve member 62 drops to open the valve and admit more mercury from reservoir 10 to restore the level 64.

When the mercury in the first boiler rises to the level of the inlet of tube 66, it interconnects electrically the electrical contact 156 which projects into the tube 66 and the electrical contact 158 which projects into the first boiler below the inlet level of the tube 66. This completes the electric circuit of the relay 160, through the closed contact B of activated relay 148.

If desired, the contact 156 may be positioned in the boiler 14 just above the inlet of tube 66, where it will be connected electrically to contact 158 through the electrically conducting mercury in the boiler.

Activation of relay 160 effects transfer of its associ ated contacts A and B from the open positions illustrated.

The manual start switch 162 then is closed momentarily to complete an electric circuit from the power supply 144 through said switch 162 and the normally closed contact B of inactivated relay 164, thence through relay 166 to the common ground. Activation of relay 166 transfers its associated contacts from the position illustrated, closure of contact C forming a holding circuit for said relay to permit release of the manual start switch.

Closure of contact A of relay 166 completes the electric circuit from terminal L through said contact and the closed contact B of activated relay 160, through the electric heater element 168 associated with the first boiler 14, thence through the adjustable heater control transformer 170 and the closed contact A of activated relay 160 to terminal L The heater thus is activated to heat the mercury in the first boiler to its boiling point. The neon lamp 168 in parallel with heater 168 also is activated with the latter to give visible indication that the first boiler is in operation.

Closure of contact B of activated relay 166 completes the electric circuit of the neon lamp 172 to provide visible indication that the first boiler 14 is in automatic operation.

Simultaneously with the momentary closing of the manual start switch 162, a second manual start switch 162' (coupled mechanically thereto as indicated by the dash line) also closes to complete the electric circuit from the power supply 144 through said switch 162 and the normally closed contact B of inactivated relay 174, thence through relay 176 to the common ground. Activation of this relay 176 transfers its associated contacts from the positions illustrated, contact C forming a holding circuit therefor, and closure of contact B completes the electric circuit of the neon lamp 178 to indicate that the second boiler 16 is ready for automatic operation.

Mercury is vaporized in the first boiler 14 and condensed in the associated condensing chamber 14' where upon it passes into the second boiler 16. When the mercury in the second boiler rises to the level of the electrical contact 180 located therein above the inlet level from the vapor trap 22, the mercury connects said contact 180 electrically to the contact 182 located in the second boiler below the contact 180. There is thus completed an electric circuit from the power supply 144 through the relay 164 and the mercury-bridged contacts 180 and 182, thence through the relay 184 and the resistance 186 to the common ground.

Activation of relay 164 transfers its associated contacts from the positions illustrated, the opening of contact B elfecting deactivation of relay 166 and the closing of contact A forming a bypass for the now opened contact A of inactivated relay 166, to maintain energized the heater 168 associated with the first boiler 14.

Activation of relay 184 and the consequent transfer of its associated contacts A and B from the positions illustrated, completes an electric circuit from terminal L through the closed contact A of activated relay 176 and the closed contact B of activated relay 184, thence through the electric heater element 188 associated with the second boiler 16, through the adjustable heater control transformer 1-90 and the closed contact A of activated relay 184 to terminal L The neon lamp 188' in parallel with the heater element 188 also is energized to give visible indication that the second boiler is in operation.

In the event the volume of mercury distillate from the first boiler 14 is greater than the volume of mercury distillate from the second boiler 16, the level of mercury in the second boiler ultimately will rise to the level of the electrical contact 192 positioned above the contact 180. When this occurs, the mercury will have interconnected said contacts electrically, thus creating an electrical shunt across the relay 164. The latter thus becomes deenergized, returning its associated contacts to the positions illustrated. Thus, with the opening of its associated contact A the electrical circuit of the heater 168 for the first boiler 14 is broken, as evidenced by deactivation of the associated neon lamp 168'. The heater 168 thus is deenergized to prevent further distillation of mercury to the second boiler, until the level of mercury in the second boiler drops below the contact 192. When this occurs, relay 164 again becomes activated and the closure of its associated contact A completes the electric circuit of the heater 168 in the first boiler.

In similar manner, when sufficient mercury has distilled over into the third boiler 18 to electrically interconnect the contacts 194 and 196 the electrical circuit from the power supply 144 is completed through the relay 174 and said contacts, thence through the relay 198 and the resistance 200 to the common ground. Activation of relay 174 causes transfer of its associated contacts, the opening of contact B deenergizing relay 176 and the closing of contact A maintaining the record boiler heater 188 activated.

Activation of relay 198 and consequent transfer of its associated contacts from the open positions illustrated, completes the electric circuit from terminal L through the normally closed contact A of relay 202 and the closed contact B of activated relay 198, thence through the electric heater element 204 associated with the third boiler 18, through the adjustable heater control transformer 206 and the closed contact A of activated relay 198 to the terminal L Activation of the neon lamp 204' gives visible indication that the third boiler is in operation.

If the volume of distillate from the second boiler 16 exceeds the output of the third boiler 18, mercury in the latter ultimately will rise to the level of the contact 208, thereby shunting the relay 174 and opening its associated contact A to deactivate the heater 188 in the second boiler 16 until such time as the mercury in the third boiler drops to a level below the contact 208.

The triple distilled mercury leaving the third condenser unit 18 through the outlet tube 28 is deposited in the receiver flask 32. As the level reaches the electrical contact 210 adjacent the bottom of the flask, it completes the electric circuit from the power supply 144 through the relay 212, thence through the contact 210 and the mercury to the common ground of the grounded flask. Activation of relay 212 results in the opening of its associated contact and consequent deactivation of the neon lamp 214 which previously had been activated to indicate that the receiver flask was empty.

When the mercury in the received flask rises to the level of the electrical contact 216 positioned adjacent the top of the flask, it completes the electric circuit of the relay 202. Transfer of the associated contact B from the relay 174 will be deactivated and its associated contact A will open to deenergize the heater element 188 in the second boiler. In similar manner, further distillation of mercury from the first boiler 14 will cease when the level of mercury in the second boiler 16 reaches the contact 192.

Cleaning of the components of the apparatus may be accomplished with disassembly. Preparatory to cleaning, the outlet tube 38 is disconnected from the supply reservoir 10 and the tube 100 is disconnected from the source of vacuum. The drain valves 74, as well as the drain valves 48 and 32 at the bottom of the feed reservoir 48 and receiver flask 32, respectively, then are opened to drain all of the mercury from the system. Thereafter the drain valves are closed, the atmosphere openings 52 and 56 and the open end of the vacuum tube 100 are plugged, and the source of vacuum is connected to the top of the receiver flask 32 through the valve connection 32". The source of coolant water is shut off, thereby opening switch 138.

Acid or other cleaning solution then is drawn in from a supply through the tube 38, to completely fill the feed device 12, flask 32, boilers and condensing chambers 96, completely to the bowls 98. The vacuum source then is disconnected, by closing valve 32", to retain the cleaning solution in the assembly. After the solution has remained in the system for a predetermined time, suitably about ten minutes, the drain valves are opened to drain the solution from the system.

The foregoing operation is repeated a number of times with water, to flush the system, then with a volatile solvent such as alcohol, acetone or other suitable liquid to remove all traces of water. Thereafter dry air is pumped through the system to assist in the removal of the solvent. Finally, the system is evacuated, by again opening valve 32", and heated to insure complete vaporization of the solvent, the latter being removed through the vacuum system.

For the purposes of heating the system, the assembly of feed device 12 and distilling units is contained within an oven which is capable of being heated by the electric heater element 220. This heater element is connected across the terminals L and L releasably through the contacts of the relays 222 and 224. The electrical circuit for relay 222 extends from the common ground through said relay, thence through a thermostat switch 226 controlled by the thermostat in the oven, thence through the manual on-off switch 228 and the normally closed contact of relay 140 (when the latter is deenergized), to the terminal L Thus, it will be apparent that the heater element 220 cannot be activated until the source of coolant liquid for the condensing units is shut off and the coolant controlled switch 138 is opened to deenergized the relay 140.

The neon lamp 230 in parallel with the relay 222 is activated with the latter to give visible indication that the heater element 220 is activated.

Relay 224 is in an electric circuit which extends from a common ground through said relay and the thermostat controlled switch 232 controlled by a second thermostat in the oven, thence through the contact of relay 140* to terminal L The switch 232 and associated relay 224 serves merely as a safety in the event of malfunction of the primary thermostat switch 226 and its associated relay 222. The primary thermostat switch 226 is set to open when the oven reaches a predetermined elevated temperature, and the thermostat switch 232 is set to open at a slightly higher temperature.

The receiver flask 32 is contained within a second oven capable of being heated by the electric heater element 234. In manner similar to the heater element 220, the element 234 is connected across the terminals L and L releasably through the contacts of the relays 236 and 238. The electrical circuit for relay 236 extends from the common ground through said relay and the primary thermostat control-led switch 240, thence through the manual on-off switch 242 and the contact of relay 140, to terminal L The neon lamp 244, in parallel with relay 236, is activated with the latter to give visible indication that the heater element 234 is activated.

The electric circuit for the safety relay 238 extends from the common ground through said relay and the safety thermostat controlled switch 246, through the contact of relay to terminal L It will be appreciated from the foregoing that the present invention provides mercury distillation apparatus Which is of simplified and compact construction, utilizing a minimum of space, provides for the continuous distillation of mercury under conditions controlled automatically by predetermined levels of mercury in the various components of the system, and is capable of being cleaned with speed and facility and without disassembly of the components.

It will be apparent to those skilled in the art that various changes may be made in the details of construction, the numbers and arrangements of parts, and the electrical circuitry, without departing from the spirit of this invention and the scope of the appended claims.

Having now described our invention and the manner in which it may be used, what we claim as new and desire to secure by Letters Patent is:

1. Mercury distillation apparatus, comprising (a) a mercury supply reservoir,

(b) a plurality of distilling units each having a boiler and a condenser,

(c) outfeed means communicating the supply reservoir with the first boiler,

(d) conduit means communicating each condenser with the next succeeding boiler,

(e) a distillate container,

(-f) conduit means communicating the last condenser with the distillate container,

(g) conduit means communicating the distillate container and distilling units with a source of vacuum,

(h) an electric heater associated with each boiler and having an electric circuit, and

(i) electric control means in the electric circuit of each heater, each control means having an electric circuit,

(j) a pair of vertically spaced electrical contact means associated with each boiler and arranged in the electric circuit of the control means for the heater of said boiler, said contact means being operable upon the attainment of a predetermined minimum level of mercury in the boiler to be interconnected electrically by the mercury in the boiler, whereby to 0perate the heater control means to activate the heater of said boiler, and

(k) a pair of vertically spaced electrical contact means in each boiler succeeding the first and arranged in the electric circuit of the control means for the heater of the next preceding boiler, said contact means being operable upon the attainment of a predetermined maximum level of mercury in the boiler to be interconnected electrically by the mercury in the boiler, whereby to operate the heater control means to inactivate the heater of the next preceding boiler.

2. The apparatus of claim 1 wherein the outfeed means includes (a) a feed reservoir having an upper annular portion and provided with an upwardly converging conical top, the top and annular portion having atmospherecommunicating openings therethrough,

(b) infeed conduit means communicating the supply reservoir with the feed reservoir through an opening in the apex of said conical top,

(c) a float member extending through the annular portion of the feed reservoir and having valve means .at its upper end for releasably sealing the apex opening of the conical top, the float member extending into the bottom portion of the feed reservoir for floating upon mercury contained therein and to close the valve means upon attainment of a predetermined elevated level of mercury in the feed reservoir whereby to maintain a substantially constant level of mercury in the feed reservoir, and

(d) outfeed conduit means communicating the feed reservoir with the first boiler.

3. The apparatus of claim 1 wherein the condensers include interconnected coolant liquid passages arranged to receive a coolant liquid therethrough, and the apparatus includes an electric switch in the elect-ric circuits of the heater control means, the switch having an operator disposed to intercept the path of coolant liquid travel and being operable by the passage of coolant liquid through the condenser passages to enable operation of the heater control means to activate the heaters.

4. Mercury distillation apparatus, comprising (a) a mercury supply reservoir,

(b) a feed reservoir,

(c) infeed conduit means communicating the top of the feed reservoir With the mercury supply reservoir,

(d) valve means adjacent the top of the feed reservoir adapted to releasably close the infeed conduit means from the feed reservoir,

(e) the valve means including a float member extending into the feed reservoir for engagement with mercury contained therein, the float member being operable to float upon the mercury and to close the valve means upon attainment of .a predetermined elevated level of mercury in the feed reservoir,

(f) a plurality of distilling units each having a boiler and a condenser,

(g) outfeed conduit means communicating the bottom of the feed reservoir with the first boiler for feeding mercury from the reservoir to said boiler,

(h) conduit means communicating each condenser with the next succeeding boiler,

(i) a distillate container,

(j) conduit means communicating the last condenser with the distillate container,

(k) conduit means communicating the distillate container and condensers with a source of vacuum,

(I) .an electric heater associated with each boiler and having an electric circuit,

(In) electric control means in the electric circuit of each heater each control means having an electric circuit,

(11) a pair of vertically spaced electrical contact means associated with each boiler and arranged in the electric circuit of the control means for the heater of said boiler, said contact means being operable upon the attainment of a predetermined minimum level of mercury in the boiler to be interconnected electrically by the mercury in the boiler, whereby to operate the heater control means to activate the heater of said boiler,

(o) a pair of vertically spaced electrical contact means in each boiler succeeding the first and arranged in the electric circuit of the control means for the heater of the next preceding boiler, said contact means being operable upon the attainment of a predetermined maximum level of mercury in the boiler to be interconnected electrically by the mercury in the boiler, whereby to operate the heater control means to inactivate the heater of the next preceding boiler,

(p) the condensers including interconnected coolant liquid passages arranged to receive a coolant liquid therethrough, and

(q) switch means in the electric circuits of the heater control means, the switch having an operator disposed to intercept the path of coolant liquid travel and being operable by the passage of coolant liquid through the condenser passages to enable operation of the heater control means to activate the heaters.

5. The apparatus of claim 4 including a pair of vertically spaced electrical contact means in the distillate container and arranged in the electric circuit of the electric control means for the heater of the last boiler, said contact means being operable upon the attainment of a predetermined maximum level of mercury in the distillate container to be interconnected electrically by the mercuny therein, whereby to operate the heater control means to inactivate the heater of the last boiler.

-6. Mercury distillation apparatus, comprising (a) a mercury supply reservoir,

(b) a plurality of distilling units each having a boiler and a condenser,

(c) outfeed means communicating the supply reservoir with the first boiler,

(d) conduit means communicating each condenser with the next succeeding boiler,

(e) a distillate container,

(f) conduit means communicating the last condenser with the distillate container,

(g) conduit means communicating the distillate container and distilling units with a source of vacuum,

(h) an electric heater associated with each boiler and having an electric circuit,

(i) electrical safety control means in the electric circuit of each heater and operable upon the attainment of a predetermined maximum level of mercury in the boilers succeeding the first to deactivate the heater associated with the next preceding boiler,

(j) the condensers including interconnected coolant liquid passages arranged to receive a coolant liquid therethrough, and

(k) an electric switch in the electric circuits of the heater control means, the switch having an operator disposed to intercept the path of coolant liquid travel and being operable by the passage of coolant liquid through the condenser passages to enable operation of the heater control means to activate the heaters.

References Cited UNITED STATES PATENTS 891,264 6/1908 Knipp 202-295 X 2,399,334 4/ 1946 Douslin 202-160 2,450,098 9/ 1948 Smith 202-206 2,547,970 4/1951 Phillips 196-132 2,598,036 5/1952 Cahill 202-181 2,642,386 6/1953 Piros 203- X 2,894,680 7/1959 Hiesinger 230-401 OTHER REFERENCES Carlsen and Borchardt: A Complete Mercury Purification System, Feb. 15, 1938, Industrial and Engineering Chemistry, Analytical edition, v. 10, pp. 14-96.

Wheeler, E. L.: Apparatus for Triple Distillation of Mercury, Analytical Chemistry, vol. 24, pp. 751-752,

NORMAN YUDKOFF, Primary Examiner. J. DONIHEE, D. EDWARDS, Assistant Examiners.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3449216 *Aug 11, 1966Jun 10, 1969Artisan IndMultistage evaporator system for the separation of monomer-solvent mixtures
US3493468 *Mar 10, 1967Feb 3, 1970Giovanni Mascarini Soc IngApparatus for automatic starting and control of vapor compression distillation
US3857704 *Mar 3, 1972Dec 31, 1974Bp Chem Int LtdMercury recovery process
US5248394 *Mar 23, 1992Sep 28, 1993Fsr Patented Technologies, Ltd.Liquid purifying/distillation device
US5441606 *Jul 14, 1992Aug 15, 1995Fsr Patented Technologies, Ltd.Liquid purifying and vacuum distillation process
Classifications
U.S. Classification202/173, 159/17.2, 202/181, 203/DIG.200, 203/1, 202/205, 324/94, 203/DIG.180, 202/206
International ClassificationC22B43/00
Cooperative ClassificationC22B43/00, Y10S203/19, Y10S203/02
European ClassificationC22B43/00