Title:
APPARATUS FOR ADDING FINELY DIVIDED SOLID MATERIAL TO A MIXTURE
United States Patent 3580422


Abstract:
This disclosure relates to apparatus for adding both a liquid and a finely divided solid to a mixture and in which the quantity of finely divided solid that is added is measured in direct proportion to the liquid deficiency of the mixture and in which the mechanism for measuring out the addition of finely divided solid is directly responsive to a liquid deficiency sensing mechanism which operates a reversible motor. The motor turns a shaft which controls both the liquid deficiency make-up mechanism and the finely divided solid make-up mechanism. The device is particularly adapted for bond compensation in a foundry where the mixture is foundry sand, water, and bond.



Inventors:
HARTLEY NELSON
Application Number:
04/778422
Publication Date:
05/25/1971
Filing Date:
11/25/1968
Assignee:
HARTLEY CONTROLS CORP.
Primary Class:
Other Classes:
177/208
International Classes:
B01F15/04; B22C5/04; B01F3/12; (IPC1-7): B67D5/56
Field of Search:
222/57,58 177
View Patent Images:



Foreign References:
GB946618A1964-01-15
Primary Examiner:
Tollberg, Stanley H.
Assistant Examiner:
Lane H. S.
Claims:
I claim

1. In apparatus to add from separate sources both a liquid and a finely divided solid to a mixture deficient in liquid and finely divided solid, said apparatus including a liquid deficiency sensing means and responding means responsive to the sensing means to control the addition of a quantity of liquid to the mixture from one source in accordance with the liquid deficiency, the improvement for adding the finely divided solid to the mixture from another source and comprising means controlled by said responding means for adding from said other source a quantity of finely divided solid in proportion to the added liquid.

2. The improvement of claim 1 in which said responding means comprises a motor and a liquid valve subject to said motor, the means for adding the finely divided solid being also subject to said motor.

3. The improvement of claim 2 in which both said liquid valve and said means for adding the finely divided solid have pneumatic operators, said motor being coupled to variable air pressure regulators for the pneumatic operators.

4. The improvement of claim 3 in which said motor is reversible, said motor having a shaft by which it is coupled to said air pressure regulators.

5. The improvement of claim 3 in which the means for adding the finely divided solid comprises a weigh hopper, means for charging finely divided solid into said hopper when it is underweight and for cutting off said charge when the hopper reaches proper weight, means for discharging hopper contents into said mixture and balance shifting means actuated by one of said pneumatic operators for changing the amount of said charge.

6. The improvement of claim 5 in which said balance shifting means comprises a balance arm by which the weigh hopper is supported, said one of sad pneumatic operators being connected to said arm at a point offset from its center of balance for shifting the balance of said arm.

7. The improvement of claim 6 in which the means for charging the finely divided solid into the hopper comprises a valve, and control means for said valve including a switch actuated by pivotal movement of said arm.

8. The improvement of claim 1 in combination with a hopper into which said finely divided solid is charged, a mixer containing said mixture and into which finely divided solid in said hopper is discharged, and means for interlocking the mixer against operation until said hopper has been fully charged with said finely divided solid.

Description:
BACKGROUND OF THE INVENTION

My copending U.S. Pat. application Ser. No. 725,117 filed Apr. 29, 1968, now abandoned in favor of copending U.S. Pat. application Ser. No. 859,544, filed Sept. 19, 1969, shows moisture tempering apparatus which is a further development of the method and apparatus shown in my U.S. Pat. Nos. 3,249,970 and 3,250,287. In said U.S. Pat. No. 3,249,970, I disclose a method and apparatus for adding a quantity of finely divided solid (typically bond) based upon the moisture deficiency of a mixture to which the finely divided solid and liquid is added.

SUMMARY OF THE INVENTION

The present invention involves a further development and improvement of the apparatus shown in my prior U.S. patents and application aforesaid, and particularly with respect to utilizing the same means which responds to the moisture deficiency sensing apparatus to add both a measured quantity of liquid and a measured quantity of finely divided solid to the mixture.

In foundry sand treatment, bound deficiency closely parallels moisture deficiency. Accordingly, excellent compensation both of moisture and bond can be obtained from the response of suitable mechanism to a signal base on the deficiency of only one of these ingredients.

As in my copending application Ser. No. 725,117 aforesaid, and using foundry sand treatment as an example of the practice of the invention, the signals from a moisture deficiency senser are utilized to actuate a reversible electric motor. The electric motor drives a shaft which controls the air pressure regulator for a pneumatic valve by which a quantity of water is added to the sand mixer which brings the sand up to proper moisture temper. In accordance with the present invention, the saMe shaft also controls an air pressure regulator for a pneumatically controlled weighing mechanism which will measure an amount of bond which will be added to the mixer to compensate for the bond deficiency of the sand therein. The weighing mechanism used for measuring out the amount of bond or other finely divided solid to be added to the mixer has its balance point changed by the pneumatic mechanism which is subject to the air pressure regulator, thus to control the amount of bond charged into a weigh hopper.

The invention also includes provision for an interlock between the bond measuring mechanism and the mixer operator so that the mixer will not be operated until the bond has been measured out in the appropriate quantity.

Other objects, features, and advantages of the invention will appear from the following disclosure.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a somewhat diagrammatic view, partly in cross section, showing a bond weighing hopper, together with the balance adjusting pneumatic motor which is subject to the air pressure regulator which, in turn, is subject to signals from the moisture deficiency senser.

FIG. 2 is a side elevation showing the air pressure regulators for the liquid valve and the bond balancing pneumatic motor, as actuated concurrently from the same reversing motor which is subject to the sensing signals from the moisture deficiency senser.

FIG. 3 is a fragmentary diagrammatic view showing the layout of the overall apparatus and indicating some of the connections therebetween.

DESCRIPTION OF PREFERRED EMBODIMENT

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

While the disclosed embodiment is specifically directed to foundry sand and bond added thereto, in its broad aspects the invention applies to the addition of any finely divided solid to a mixture to which liquid is also added and in which the amount of finely divided solid to be added is in proportion to the amount of liquid also to be added.

The disclosure of my copending U.S. Pat. application Ser. No. 725,117 filed Apr. 29, 1968, and copending U.S. Pat. application Ser. No. 859,544, filed signals from 19, 1969, is incorporated herein by reference. This disclosure, incorporated herein by reference, goes into detail with respect to sensing moisture deficiency or excess in a finely divided material, such as foundry sand. A reversible motor is actuated in accordance with the signals from the sensers. The motor adjusts the pressure of an air pressure regulator which controls the operation of a valve in a water line to admit sufficient water to balance the moisture deficiency of the finely divided material in the mixer.

The apparatus of the present invention utilizes the same instrumentalities and circuits as shown, for example, in FIG. 5 of my copending application aforesaid. In addition, the present invention features mechanism to add bond to the foundry sand in a sufficient quantity to make up for the bond deficiency thereof, all in accordance with the signals fed back from the sensers exposed to the material undergoing treatment. In this application, I shown in FIG. 3 only the overall layout in which the material to be mixed is first delivered to a batch hopper 10 and then through gate 9 to a mixer 11. After mixing, the material is dumped from the mixer 11 through a gate 12 and is delivered by conveyor belt to molders hoppers or other points of use.

As in my prior application, there is a senser 13 in the batch hopper 10 and a senser 14 in the mixer. Both of these sensers are connected through electric apparatus, such as shown in FIG. 5 of my copending application aforesaid, for the purpose of running a reversible electric motor 15 selectively in its forward or reverse direction for the purposes stated in my prior application. As in the prior application, one such purpose is for adjustment of the air pressure on diaphragm 16 of valve 17 in water line 18. Sufficient water will be admitted through the line 18 to exactly balance the moisture deficiency of the finely divided material which is being processed through the batch hopper 10 and mixer 11.

As shown in FIG. 2, the motor is geared to a shaft 21 which is geared through the bevel gears 22 to an air pressure regulator 23 which is in the air line 24, by which the diaphragm 16 is energized. In accordance with the present invention, the same motor 15 and shaft 21 drive through bevel gears 25 to an air pressure regulator 26, which is in air line 27 to pneumatic motor 28 associated with the weigh hopper 31. Hopper 31 is suspended above the batch hopper 10. Bond or like finely divided solid material is delivered through the pipe 32 into hopper 31.

The shaft 21 also drives variable transformer 34, through bevel gears 33. Transformer 34 is also shown at 24 in FIG. 5 of my prior application, for the same purposes.

Weigh hopper 31 is supported on the arm 35 which is pivotally supported on the pintle 36 from frame 37. The weight of the hopper 31 is counteracted by the balance motor 28. By changing the air pressure within the motor 28, the amount of bond which can be admitted into the hopper 31 before arm 35 will pivot about pintle 36 (counterclockwise in FIG. 1) can be adjusted. Pivotal movement of arm 35 about pintle 36 is limited by the stops 40, 41.

The rear end of arm 35 is provided with actuator arm 42 for contact stem 39 of the paired contacts 51, 72 within switch 43.

FIG. 1 illustrates the point in the operating cycle when the hopper is empty. Accordingly, the upward pressure of motor 28 is normally sufficient to swing the arm 35 clockwise about pintle 36 until arm 35 engages stop 40 and arm 42 has retracted from switch 43. If bound or like finely divided material is now supplied to the hopper 31 through the pipe 32, the hopper will begin to fill up with such material until the weight of the hopper increases to the point where it will overbalance the upward pressure of the motor 28 and cause the support arm 35 to tilt counterclockwise about pivot 36. This will swing arm 42 to actuate switch 43, thus closing contact 51 and shutting off the flow of bond into the hopper 31, as hereinafter described.

Accordingly, the amount of bond which is charged into the hopper 31 will depend on the amount of air pressure existing in the pneumatic motor 28. To adjust the amount of bond charged into the hopper 31, the air pressure in the pneumatic motor 28 will be regulated by the air pressure regulator 26, as hereinafter described.

The bond supply pipe 32 is provided with a charging valve 44 which closes off the admission of bond when it is in its position shown in FIG. 1. The charging valve 44 is connected to pneumatic motor which is fed with air through pipes 46, 47 under control of a solenoid actuated valve 48. Valve 48 is under control of one contact 51 in switch 43.

The hopper 31 has a deflecting baffle 52 which promotes even filling of the hopper 31. The discharge spout 53 of the hopper 31 is provided with a plug valve 54 mounted on a hollow stem 55 through which air is supplied under pressure through the air line 56, in order to jet air through orifices 57 in the nozzle 58 just above the plug 54. Accordingly, this air will maintain the finely divided solid material in the hopper in a state of fluid suspension, thus to avoid clogging the spout 53 when the valve plug 54 is withdrawn therefrom.

Valve plug 54 is actuated by an air motor 61 which has an internal piston connected to the piston rod 62, which, in turn, is connected to the hollow stem 55. Air is supplied to the motor 61 through the air pipes 63, 64, and a control valve 65. Motor 61 is energized to close the plug 54 until the appropriate amount of bond or other finely divided material has been charged into the weigh hopper 31. After charging has terminated and the point in the cycle is reached where the accumulated bond is to be discharged into the batch hopper 10 and thence to the mixer 11, cylinder 61 is actuated, for example, by a cam controlled switch 60, to pull the plug 54, whereupon the contents of the hopper 31 are delivered by gravity into batch hopper 10.

Control for various operations in the cycle is generally effected through a cam shaft 66 (FIG. 3) on the shaft of motor 67. Cam shaft 66 carries a series of cams, such as cam 68. The cams cooperate with a series of contactors, such as contactors 60, 71, etc. One such cam energizes the drive motor for the mixer 11. There is an interlock, however, which prevents operation of the cam motor 67 until the bond has been measured out and fully charged into the hopper 31. This interlock includes contact 72 in the electrical line to the motor 67. This contact 72 is disposed within the switch box 43 and is subject to the switch actuator 42 on balance arm 35. Accordingly, the mixer 11 is interlocked against the start of the mixing operation until the bond has been measured out and fully charged into the hopper 31.

As shown in FIG. 1, I also provide a manual override valve 73 by which a fixed quantity of bond can be introduced into the hopper 31 without regard to the control air pressure regulator 26. Valve 74, in series with the air pressure regulator 23, can be closed to render the regulator 23 ineffective. Valve 75 in series with valve 73 can be opened, whereupon the manual override valve 73 can be set to pressurize line 27 in accordance with the reading on the gauge 76 which can be calibrated in terms of an absolute quantity of finely divided solid material which will be added to the hopper 31. This manual override is useful particularly in environments other than foundry sand treatment where there is no predetermined relationship between the quantity of finely divided material and the moisture deficiency of the material in the hopper 10.

An advantage of utilizing separate air regulators 23 and 26 for control respectively of water and bond addition, is that the air pressure range can be set independently for each function. Note the difference in sizes of the bevel gear sets 22, 25 in FIG. 2. Nevertheless, both regulators 23, 26 are concurrently actuated.

From the foregoing it is clear that liquid deficiency sensing means such as the sensers 13, 14 signal a responding means including an operator such as motor 15 to add to the mixer a quantity of liquid in accordance with the liquid deficiency. At the same time, the responding means actuates means such as the air pressure regulator 26 for adding a quantity of finely divided solid in proportion to the added liquid.