US2030725A - Means for controlling temperatures in the refrigerating systems of package sealing machines - Google Patents

Description

2,030,725 TEMPERATURES IN THE REFRIGERA PACKAGE SEALING MACHINES TING Feb. 11, 1936. M. A. STICELBER MEANS FOR CONTROLLING SYSTEMS 0F Filed Nov. 16, 1934 INVENTOR. W//ll/Y fifizaelez' -w/ ATTORNEYS.

r lulll'l'll Illllllll I Patented tab. 11, 1936 UNITED- STATES PATENT OFFiCE MEANS FOR CONTROLLING TEMPERA- TUBES IN THE REFRIGERATING SYSTEMS F PACKAGE SEALING MACHINES Merlin A. Sticelber, Kansas City,-Mo., assignor of one-half City, Mo.

,to William Stoneman, J12, Kansas Application November 16, 1934, Serial No. 753.270

15 Claims.

such a means, wherein is embodied automatic structure which causes the temperature at the evaporation means of the refrigerating system to be maintained at a predetermined, set temperature when the wrapping machine is in operation and another automatic structure for maintaining the temperature at the evaporation means of the refrigerating system at a higher temperature when the machine is not in operation.

A yet further object of this invention is the provision of, temperature control means for refrigcrating systems of the sealing units for wrapping machines which combines with the mechanism for starting and stopping the said wrapping machine in an unique and novel manner, to the end that the necessary relatively low temperature is maintained in the evaporation means of the sealing unit while the wrapping machine is in operation to move packages through said unit, yet to maintain an appreciably higher temperature at the evaporation means when the'wrapping machine is idle, said system being automatically operable as the controls for starting and stopping the wrapping machine are either manually or otherwise actuated for the purpose of starting and/or stopping the passage of packages to be sealed through the sealing unit.

An even further object of the present invention is to combine with the manual control for starting. and stopping a wrapping machine, means for rendering effective or'non-effective,

one or the other of a pair of thermostats, each of which is operably joined to a portion of the refrigerating system in the sealing unit of the wrapping machine whereby temperatures necessary are automatically maintained at the evapo--- rati"n means of the unit.

Another important aim of the invention is to provide electrical circuits of unique character for accomplishing the broad objects of the invention, said circuits including not only the motor which drives the compressor of the refrigerating system, but an electrically operated magnetic valve psitioned in the conduit for supplying liquid re- JO frigeran't to the evaporator coils, said valve being disposed immediately adjacent the expansion valve in said conduit. I

Structural details and specific combinations of the various parts of the temperature controlling means form definite and important objects of this invention and the same will become apparent during the course of the following specification, referring to the accompanying drawing, wherein:

Figure l is a schematic view illustrating the means for controlling temperatures in refrigerv ating systems that are employed in sealing units of wrapping machines.

Fig. 2 is an enlarged, detailed, fragmentary, sectional view through electrically operated magnetic valve forming a part of this control system.

In the art of wrapping packages it is'a well known fact that the wax paper is subjected to heat and then to a low temperature for the purpose of first melting the wax at the point of seal, and then quickly solidifying the same in order that the package might be fed from the wrapping machine at once and in a perfectly safe condition for handling.

In bread wrapping machines with which this invention is particularly adapted for use, the package seals must be extremely rigid for in a greater percentage of instances, the bread being wrapped is sliced and therefore the waxed paper is called upon to serve as means for holding the sliced bread in a compact condition.

It has been found highly desirable, if not abso lutely necessary, to provide sealing units for bread wrapping machines which embody a refrigerating system in a manner set forth in my co-pending application for United States Letters Patent Serial Number 736,563, filed July 23, 1934,

and relating to improvements in Sealing machine. A refrigerating system such as disclosed in said application is commercially practical and produces a seal strong enough to meet the drastic 4 requirements of the trade.

To render this refrigerating system still more 'emcient, to eliminate the possibility of injury to any of the parts of the refrigerator system, and to render the entire machine more eflicient with respect to current consumption, the automatic means for controlling the temperatures at the evaporation means of the refrigerating system of my sealing unit has been devised and found especially desirable.

Plates 8 correspond to similarly numbered plates in the aforementioned co-pending application andare those forming a part of the wrapping machine which should be hot enough to melt the wax on the paper; wrapper. In this instance, belt I0 is "illustrated as means for moving the wrapped packages from plates 8 to the sealing unit I Land a motor ll actuates this belt, as well as the other parts of the wrapping machine,

not here shown. When motor I4 is started and '55 stopped, the wrapping machine, including conveyor belt I8 or any other means for moving the packages, will likewise be started and stopped. This motor circuit includes any suitable switch having points I6 and I8 and a handle or other medium 28 for opening and closing the said points. The circuit for motor I4 which operates the wrapping machine may be traced as follows: From one wire 22 of the power supply through wire 24, motor I4, wire 26, closed points It and I8, and then through wire 28 to the other wire 38 of the power supply means.

The sealing unit I2 includes the'refrigerated plates 32 and 34 which directly and frictionally contact the zones of the wrapper that must be cooled after the melting operation that has been performed by plates or similar means 8. The refrigerating system forming a part of the sealing unit includes evaporation coils 36, for the side plates 32 and similar coils 38, for the bottom plate 34. These coils are continuous and maintain the associated plates at the desired temperature as hereinafter set forth. A compressor 48,

driven by the ordinary motor 42, has a pipe 44 through which is forced the compressed vaprous refrigerant into condenser 46, from where the liquid refrigerant passes to the aforementioned evaporation coils 36 and 38 through the medium of pipe 48.

' An expansion valve 58 of the conventional type is interposed in conduit 48 adjacent the evaporation coils and an electromagnetic valve 52 is also positioned in this conduit 48 immediately adjacent expansion valve 58. This valve 52 is detailed in Fig. 2 and comprises port 54 which is closed by plunger 56 when the same is seated. A spring 58 urges plunger 56 down against the annular edge of port 54, but so long as the circuit including the coil 68 of this valve 52 is closed, the magnetic force will hold plunger 56 in the open position. When this valve 52 is closed but a very small amount of liquid refrigerant can possibly flow to compressor 48. As a matter of fact, only the liquid refrigerant which is in conduit 48 between valve 52 and expansion valve 58 can flow to the compressor '48.

A conduit or other suitable'means 62 connects evaporator coils 36 and 38 with compressor 48 and it is upon this means that the two thermostats 64 and 66 are mounted for the purpose of maintaining two separate and distinct temperatures during the operation of the machine. These thermostats may be of the mercury bulb 'type and the mercury containers are clamped as at 68 and I8 directly to the return line 62 and joined to thermostats 64 and 66 respectively by tubes 12 and 14 respectively. The thermostat 64 moves electrical contact 16 to and. from contact point 18 whereby to periodically open and close the switch formed by said contacts as the temperature in conduit 62 varies from the predetermined twenty-one degrees. Thermostat 66 periodically moves movable contact point 88 to and from contact point 82 as the temperature in return line 62 varies from the predetermined amount of fourteen degrees. Thermostat 64 has a switch 84 which is manually operated to render effective the thermostat and thermostat 66 has a similar main manually operable switch 86 for the same purpose.

When the wrapping machine is in operation and a great amount of heat exchange is taking place at plates 32 and 34, the temperature at said plates must be maintained at a relatively it v degree. Thermostat 86, therefore, is controlling the operation of compressor 48 to maintain the low temperature and, in practice, such temperature should be about fourteen degrees Fahrenheit.

When the wrapping machine is not in operation, there is very little heat exchange at the sealing unit and a higher temperature should be maintained. When the wrapping machine, therefore, is not in operation, thermostat 64 should be controlling the action'of compressor 48. In either instance, valve 52 is opened and closed by the action of either thermostat. That is to say, when either thermostat 64 or 66 is controlling the action of compressor 48, valve 52 is closed when compressor 48 is not supplying refrigerant to the evaporation means and is open when compressor 48 is supplying, refrigerant to the evaporation means.

The means for uniquely combining the two aforesaid thermostats with the means which operates the wrapping machine is a simple, yet novel one and comprises a pair of movable electrical contacts 88 and 98, which are moved to and from stationary electrical contacts 92 and 94 as contact points I6 and I8 of the circuit of motor I4 are moved toward and from each other to start and stop the wrapping machine. 'When the wrap ping machine is in operation, contact points I6 and I8 are together to cause motor I4 to drive the said machine, and contact points 88 and 92 are together to insure that thermostat 66 is controlling the temperature at plates 32 and 34, which temperature should be relatively low, or approximately fourteen degrees Fahrenheit.

When the wrapping machine is not in operation, contact points I6 and I8 are apart, thus to render idle motor I4, contact points 98 and.94 are together, and thermostat 64 is in operative relation with compressor 48 and plates 32 and-34 of the evaporation means. Obviously, the relatively high temperature of twenty-one degrees will be maintained providing the thermostat 64 is so set. The differential above set down has been found practical in bread wrapping machines.

When the wrapping machine is in operation, the circuit employed which includes thermostat 86, is as follows: 'Wire 22, wire 96, motor 42, wire 98, coil 68, wire I88, wire I82, switch 86, points 88 and 82, when motor 42 is running, wire I84, contact points 88 and 92, wire I88, wire I 88 to the other side of the supply line, wire 38.

When the wrapping machine is not in operation to pass packages through the sealing unit, the circuit, which includes thermostat 64, but not thermostat 66, is as follows: From supply line 22 to wire 96, motor 42, wire 98, coil 68, wire I88,

wire I I8, switch 84, contact points 18 and 18, wire II2, contact points 98 and 94, wire II4, wire I88 to the other side of the supply line, wire 38.

Obviously, valve 52 is in both circuits. When the appropriate contact points at either thermostat are parted, coil 68 will be de-energized and spring 58 will force plunger 56 to the closed position. Since motor 42 is likewise in both circuits, the opening and closing of that circuit will stop and start respectively motor 42 of compressor 48.

Whether or not one or the other of the two thermostats is controlling the action of the refrigerating system depends upon the position of lever 28 which is joined to movable contact points 88 and 98 by suitable linkage II6. When the machine is started and stopped by the opening and closing of points I6 and I8, the appropriate thermostat will be rendered operative by the machines comprising evaporation means disposed in heat-exchanging relation with the packages being moved through the machine; means for supplying a refrigerant to the evaporation means; means for conveying refrigerant from the evaporation means; electrically operated means, having an electrical circuit, for operating the sealing machine to convey packages therethrough; a switch to open and close the said circuit; a pair of thermostats each responsive to a predetermined different temperature in connection with the means for conveying the refrigerant from the evaporation means; a switch operable by each thermostat respectively; an electrical circuit for each switch respectively; an electrically operated valve for stopping the supply of refrigerant to the evaporation means when the circuit supplying energy theretois open; and meansfor automatically rendering said valve operable by one thermostatically operated switch when the sealing machine operating means is in operation and for automatically rendering said valve operable by the other thermostatically operated switch circuit when the sealing machine operating means is idle.

2. A refrigerating system for package sealing machines comprising evaporation means disposed in heat-exchanging relation with the packages being moved through the machine; means for supplying a refrigerant to the evaporation means;

means for conveying refrigerant from the evaporation means; electrically operated means, having an electrical circuit, for operating the sealing machine to convey packages therethrough; a switch to open and close the said circuit; a pair of thermostats each responsive to a predetermined different temperature in connection with the means for conveying the refrigerant from the evaporation means; a switch operable by each thermostat respectively; an electrical circuit for each switch respectively; an electrically operated valve for stopping the supply of refrigerant to the evaporation means when the circuit supplying energy thereto is open; a switch to open and close the circuit of the said means for operating the sealing machine; and means for rendering said valve operable by one thermostatically operated switch when the said last mentioned switch is closed and for rendering said valve operable by the other thermostatically operated switch when the said switch is open.

3. A refrigerating system for package sealing machines comprising evaporation means disposed in heat-exchanging relation with the packages being moved through the machine; means for supplying a refrigerant to the evaporation means; means for conveying refrigerant from the evaporation means; electrically operated means, hav-'- ing an electrical circuit, for operating the sealing machine to convey packages therethrough; a switch to open and close the said circuit; a

thermostat responsive to a predetermined tempera-ture in connection with the means for conveying the refrigerant from the evaporation means; another thermostat responsive to a predetermined temperature lower than the first mentioned thermostat also in connection with the means for conveying the refrigerant from the thermostat respectively; an electrical circuit for each switch respectively; an electrically operated valve for stopping the supply of refrigerant to the evaporation means when the circuit supplying energy thereto is open; and means for automatically rendering said valve operable by the first mentioned thermostat of relative high temperature responsiveness when the sealing machine operating means is inoperative, and for automatically rendering said valve operable by the second mentioned thermostat of relatively low temperature responsiveness when the sealing meansoperating means is operative. I

4. A refrigerating system for package sealing machines comprising a motor driven compressor; a motor circuit; evaporation means disposed in heat-exchanging relation with the packages being moved through the machine; means for conveying refrigerant from the evaporation means to the compressor; electrically operated means having an electrical circuit with a switch for operating the sealing machine to convey packages therethrough; a pair of thermostats each responsive to a predetermined different tempera ture in connection with the means for conveying the refrigerant from the evaporation means to the compressor; a switch operable by each thermostat respectively each in a different circuit, both of the circuits including the said motor circuit whereby the compressor motor is started and stopped when either thermostat switch is closed or opened respectively by its associated machine to convey packages therethrough; a

switch to open and close the said circuit; a thermostat responsive to 'a predetermined temperature in connection with the means for conveying the refrigerant from the evaporation means; another thermostat responsive to a pre- L determined temperature lower than the first mentioned thermostat also in connection with the means for conveying the refrigerant from the evaporation means; a switch operable by each thermostat respectively; an electrical circuit for each switch respectively; an electrically operated valve for stopping the supply of refrigerant to the evaporation means when the circuit supplying energy thereto is open; and means for automatically rendering said valve operable by the first mentioned thermostat of relative high temperature responsiveness when the sealing Inachine operating means is inoperative, and for automatically rendering said valve operable by the second mentioned thermostat of relatively low temperature responsiveness when the sealing means-operating means is operative, said means for supplying a refrigerant to the evaporation .means including a motor driven compressor and a circuit to supply electrical energy to said mo tor, said compressor motor circuit being in connection with both of said thermostatically op-, erated switches whereby when either thermostat is in operation, the said compressor motor circuit is opened and closed by its associated switch as the temperature of the refrigerant in the conveying means varies.

6. A refrigerating system for package sealing machines comprising a motor driven compressor; a motor circuit; evaporation means disposed in heat-exchanging relation with the packages being moved through the machine; means for con veying refrigerant from the evaporation means to the compressor; electrically operated means having an electrical circuit with a switch for operating the sealing machine to convey packages therethrough; a pair of thermostats each responsive to a predetermined different temperature in connection with the means for conveying the refrigerant from the evaporation means to the'compressor; a switch operable by each thermostat respectively each in a different circuit, both of the circuits including the said motor circuit whereby the compressor motor is started and stopped when either thermostat switch is closed or opened respectively by its associated thermostat; and means operable by the closing of the switch in the circuit of the means for operating the sealing machine to convey packages therethrough, for rendering one of the thermostats effective and the other ineffective and for rendering the first mentioned thermostat ineffective and the last mentioned thermostat effective when the said switch is opened to stop the operation of the sealing machine.

7. In a sealing unit for a wrapping machine, the combination with plates for contacting the packages to seal the same and refrigeration means for cooling said plates, of means for maintaining a predetermined temperature at the plates when the wrapping machine is operating to pass packages through the sealing unit, said means being rendered operative as the wrapping ma-- chine is started and inoperative as the said ma chine is stopped.

8; In a sealing unit for a wrapping machine, the combination with plates for contacting the packages to seal the same and refrigeration means for cooling said plates, of means for maintaining a predetermined temperature at the plates when the wrapping machine is idle, said means being rendered operative as the machine is stopped and inoperative as the machine is started.

9. In a sealing unit for a wrapping machine, the combination with plates for contacting the packages to seal the same and refrigeration means for cooling said plates, of means for maintaining a predetermined temperature at the plates when the wrapping machine is operating to pass packages through the sealing unit, and for maintaining a relatively high temperature at the plates when the wrapping machine is idle, said means for maintaining the two different temperatures being automatically rendered operative as: the means for starting and stopping respectively the wrapping machine is operated.

10. In a sealing unit for a wrapping machine, the combination with plates for contacting the packages to seal the same and refrigeration means for cooling said plates, of means for maintaining a predetermined temperature at the plates when the wrapping machine is operating to pass packages through the sealing unit, and for maintaining a relatively high temperature at the plates when the wrapping machine is idle, said means for maintaining the twodifierent temperatures being automatically rendered operative as the means for starting and stopping respectively the answer wrapping machine, one of the temperature maintaining means being rendered inoperative as the other is rendered operative when the said starting and stopping means of the wrapping machine is operated.

11. In a sealing unit for wrapping machines, the combination with elements for contacting the packages to seal the same and refrigeration means for cooling said elements, of means for maintaining a predetermined temperature at the elements when the wrapping machine is operating to pass packages through the sealing unit and another means for maintaining a relatively high temperature at the elements when the wrap ping machine is idle, said means being automatically rendered efiective as the wrapping machine is started and stopped respectively, both of said temperature control means being operatively joined to the refrigeration means for stopping its action when either of the temperature control means is actuated by the dropping of the temperature at the elements below the predetermined set temperature for each respective maintaining means.

12. In a sealing unit for wrapping machines, the combination with elements for contacting the packages to seal the same and refrigeration means for cooling said elements, of means for maintaining a predetermined temperature at the. elements when the wrapping machine is operating to pass packages through the sealing unit and another means for maintaining a relatively high temperature at the elements when the wrapping machine is idle, said means being automatically rendered effective as the wrapping machine is started and stopped respectively, both of said temperature control means being operatively joined to a valve in the refrigeration line and the compressor of the refrigeration system for stopping the flow of refrigerant through the refrigeration system in either direction when either oi the temperature control means is actuated by the dropping of the temperature at the elements below the predetermined set temperature for each respective maintaining means.

13. In a sealing unit for wrapping machines, the combination with elements for contacting the packages to seal the same and refrigeration means for cooling said elements, of means for maintaining a predetermined temperature at the elements when the wrapping machine is operating to pass packages through the sealing unit and another means for maintaining a relatively high temperature at the elements when the wrapping machine is idle, said means being automatically rendered effective as the wrapping machine is started and stopped respectively, both of said temperature control means being operatively joined to a valve in the refrigeration line and the compressor of the refrigeration system for stopping the flow of refrigerant through the refrigeration system in either direction when either of the temperature control means is actuated by the dropping of the temperature at the elements below the predetermined set temperature for each respective maintaining means, said valve being maintained open and the compressor of the refrigeration system in operation so long as the temperature at the sealing element remains the same as the predetermined set temperature of the control means in effect.

14. In a sealing unit for wrapping machines, the combination with elements for contacting the packages to seal the same and refrigeration means for cooling said elements, of means for maintaining a predetermined temperature at the elements when the wrapping machine is operating to pass packages through the sealing unitand another means for maintaining a relatively high temperature. at the elements when the wrapping machine is idle, said means being automatically rendered eifective as the wrapping machine is started and stopped respectively, both of said temperature control means being operatively joined to a valve in the refrigeration line and the compressor of the refrigeration system for stopping the flow of refrigerant through the refrigeration system in either direction when either of the temperature control means is actuated by the dropping of the temperature at the elements below the predetermined set temperature for each respective maintaining means, said valve being maintained open and the compressor of the refrigeration system in operation so long as the temperature at the sealing element remains the same'as the predetermined set temperature of the control means in effect, said refrigeration system having an expansion valve therein and the aforementioned valve being immediately adjacent thereto between the said expansion valve and the compressor. 7

15. In a sealing unit for wrapping machines of the character described, a refrigerating system 5 to cool the seal of the packages; a switch to start and stop the wrapping machine; a thermostat having a circuit controlling the compressor motor of the said system to maintain a predetermined temperature in the evaporation means of 10 the system; another thermostat having a circuit also controlling the compressor motor of the said system to maintain a different predetermined temperature in the evaporation means of the system; and a switch in each aforesaid thermo- 15 stat circuit respectively inoperative connection with the starting switch of the wrapping ma chine whereby one of the said thermostats is effective to control the compressor motor when the wrapping machine is in operation and the other 20 of said thermostats is effectivefor the same purpose when the wrapping machine is idle.

' MERLIN A. STICELBER.

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