Abstract:
An improved product filling device for filling containers has a zero clearance rotor valve engaging the interior of a rotor valve housing. The rotor has a tapered conical sealing surface engaged with a complimentary conical seating surface in the housing. The position of the rotor allows product to enter a cylinder and be discharged from the cylinder into a container via movement of a piston inside the cylinder. Alternative structures and methods are disclosed.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of provisional patent application Ser. No. 60/437,755 filed Jan. 3, 2003 entitled “ZERO CLEARANCE ROTOR VALVE FOR PRODUCT FILLING.” 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to filling devices for filling containers; and in particular to a filling device using a zero clearance rotor valve. 
     BACKGROUND OF THE INVENTION 
     Food products that are substantially flowable, such as margarine, butter, sour cream, ice cream, yogurt or the like, typically are packaged in individual containers for retail sale and consumer use. Packaging of these types of food products is ordinarily effected with the use of fill pump devices and associated container conveyors that present containers in a continuous, sequential manner to the filling device which is operated to dispense food product to each of the containers. 
     In such systems, precise control of the filling device is necessary in order to assure that each container receives the desired quantity of product. In practice, such precision can be difficult to achieve due to inherent fluctuations in product consistency and temperature as well as the periodic start-up and shut-down of a filling line which typically complicates accurate filling of the containers. 
     Existing filling devices or fillers use a cylindrical, plastic rotor in a cylindrical, stainless steel housing to control the amount of product dispensed to each of the containers. Such fillers require a large clearance between the rotor and the stainless steel housing to allow for thermal expansion of the rotor due to changes in ambient or product temperature. This large clearance allows variable amounts of the metered volume of product to leak back into the supply system during dispensing, which leads to inconsistent fill weights. This clearance also allows product to leak from the supply system to the discharge, causing dripping of product between fills. 
     As can be readily appreciated, the ability to efficiently internally clean the valve assembly of a filling device is a primary concern when dealing with food products. Known valve assemblies of filling devices ordinarily require substantially complete disassembly to effect internal cleaning of the component parts of the valve assembly. Even frequent internal cleaning of the valve assembly may not properly retard bacterial growth and the like, which could lead to contamination of food product passing through the valve assembly. Disassembly of the valve assembly for cleaning purposes is a time consuming process involving substantial interruption of the production line. 
     Therefore, there is a need for a product filling apparatus which may be cleaned in place without disassembly. There is further a need for a product filling method and apparatus which permits versatile, dependable operation of a filling system while maintaining the appropriate product weight and appearance under a wide variety of operating conditions. 
     SUMMARY OF THE INVENTION 
     Products are filled into open containers according to the invention through use of a zero clearance rotor valve combined with a pressure filled metering cylinder. The invention comprises product supply piping, a rotor housing inside which rotates a rotor in zero clearance therewith, a rotor drive mechanism, a metering cylinder inside which moves a piston and a piston drive mechanism. The product supply piping is connected to the top of the rotor housing and the cylinder is connected to one side of the rotor housing. The rotor housing also has an opening on the bottom through which the product flows into the container. The rotor sits inside the rotor housing and has a conical-shaped sealing end with two separate passages or channels cut into it. One passage allows product to flow from the product supply piping into the cylinder. The other passage allows product to flow from the cylinder out to the container when the rotor is shifted (rotated) from a first or prime position to a second or fill position by the rotor drive mechanism. The piston is moved back and forth or reciprocated inside the cylinder by the piston drive mechanism. The location, size and geometry of the passages in the rotor and rotor housing, together with the zero clearance fit, do not allow product to leak from the product supply to either the cylinder or the container. 
     The conical shape and zero clearance fit of the rotor and rotor housing and the location, size and geometry of the passages in the rotor allow for tight shut off of product. This tight shut off leads to very consistent product fill weights and eliminates leaking of product between fills. The accuracy of the filler is not affected by changes in ambient or product temperature, since the conical sealing surface of the rotor remains in contact with the housing while allowing for expansion. 
     Moreover, the geometry of the rotor and rotor housing also make this invention easy to clean in place without disassembly. Even though there is operationally a zero clearance between the tapered convex or conical rotor sealing surface of the rotor and its complimentary tapered concave seating surface in the rotor housing, a large clearance between the non-sealing surfaces of the rotor and the rotor housing can be obtained, with a short, backwards movement of the rotor away from the seating surface of the rotor housing. After such movement, all surfaces of the rotor and rotor housing have enough clearance to be cleaned without disassembly. Cleaning solution can flow more easily through the rotor and rotor housing passages, making cleaning faster and more efficient. Cleaning fluid temperatures do not adversely affect rotor motions due to thermal expansion of the components. 
     The zero clearance sealing surface of the rotor valve also provides an excellent cut-off of product at the end of fill due to the scissor action across the discharge opening in the rotor housing. This allows particles and thick products, such as pieces of fruit, for example, to be cut cleanly without the need for additional cut-off spouting after the rotor valve. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Details of a zero clearance rotor valve for product filling according to the invention are shown in the attached drawings in which: 
     FIG. 1 is a perspective view of the assembled invention; 
     FIG. 2 is a top plan view of the invention of FIG. 1; 
     FIG. 3 is a cross-sectional view taken along line  3 — 3  of FIG. 2, and extended to show the piston end not in FIG. 2; 
     FIG. 3A is an enlarged view of the circled area  3 A of FIG. 3; 
     FIG. 4 is a cross-sectional view similar to FIG. 3 illustrating a “prime” operation or “metering fill” of the invention; 
     FIG. 5 is a cross-sectional view similar to FIG. 3 but illustrating a filling operation of the invention; 
     FIGS. 6-9 illustrate the features of the rotor of the invention; 
     FIG. 10 is a perspective illustration of a rotor housing according to the invention; and 
     FIG. 11 is another perspective illustration of the rotor housing of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings and particularly to FIG. 1, there is illustrated a filling apparatus or filler  10  in accordance with the present invention. The filler  10  comprises a rotor valve housing  12 , a rotor valve or rotor  14  (see FIGS. 6-9) driven by a rotor drive mechanism (not shown) and a piston  16  movable inside a product metering cylinder or chamber  18  via a piston drive mechanism (not shown). Together the piston  16  and product metering cylinder  18  are herein referred to as a product metering means. 
     A product supply pipe  20  is secured to the rotor valve housing  12  in any suitable manner and extends upwardly from the rotor valve housing  12  as shown in FIG.  1 . The product supply pipe  20  has an outer wall  21  which defines a conduit  23  therein. Although one configuration of product supply pipe  20  is illustrated, any other configuration of product supply pipe may be used in accordance with the present invention. 
     As best illustrated in FIGS. 10 and 11, the rotor valve housing  12  has a body  22  having a top surface  24 , a bottom surface  25 , a front surface  26 , a rear surface  27 , two side surfaces  28  and a mounting surface  29 . Although one configuration of rotor valve housing  12  is illustrated, any other configuration of rotor valve housing may be used in accordance with the present invention. Depending on the orientation of the filler  10  of the present invention, the surfaces of the rotor valve housing  12  may be oriented differently than the orientation shown in the drawings and described herein. For example, the front surface  26  of the rotor valve housing  12  may be located behind the surface herein referred to as the rear surface  27 . Therefore, the names of the surfaces are merely for identification purposes and are not to be strictly interpreted. 
     As shown in FIG. 3, the body  22  of the rotor valve housing  12  has a cavity  30  therein in which is located the rotor  14 . As best illustrated in FIG. 1, a removable cover  31  is removably secured to the body  22  of the rotor valve housing  12  with fasteners  33  which extend into openings  35  in the generally planar mounting surface  29  of the rotor valve housing  12 . See FIGS. 10 and 11. The removable cover  31  functions to cover the cavity  30  and enables the rotor  14  to be removed from the cavity  30  for repair or replacement. 
     As best illustrated in FIG. 3, the rotor valve housing  12  has a product receiving port  32  located in the top surface  24  thereof, a metering cylinder port  34  located in the rear surface  27  thereof and a product discharge port  36  in the bottom surface  25  thereof. As shown in FIGS. 10 and 11, the cavity  30  of the rotor valve housing  12  further has a side surface  37  and a conically-shaped seating surface  38  in which the metering cylinder port  34  and product discharge port  36  are defined. Although the drawings illustrate particular sizes and configurations, the product receiving port  32 , a metering cylinder port  34  and product discharge port  36  may be any desired size and any desired shape or configuration. 
     As illustrated in FIG. 3, the body  22  of the rotor valve housing  12  has a conduit  40  therein which communicates with the conduit  23  of the product supply pipe  20 . The conduit  40  extends inwardly from the top surface  24  of the rotor valve housing  12  and terminates at the cavity  30  of the housing body  22 . The product receiving port  32  is located at the upper end of the conduit  40  and a product loading port  42  is located at the lower end of the conduit  40 . See FIG.  3 . 
     The rotor  14  is located in the cavity  30  of the rotor valve housing  12  and has an outer surface  15 . The rotor  14  is rotatable therein via a drive mechanism (not shown) as shown by arrow  39 . As best illustrated in FIGS. 6-9, the rotor  14  has a generally conical sealing end portion  44  at the end of a generally cylindrical body portion  46 . The generally conical sealing end portion  44  has an outer surface  48  and a generally planar end surface  50 , best illustrated in FIGS. 6,  7  and  8 . As best seen in FIG. 7, a pair of spaced ridges  52  extend outwardly from the outer surface  54  of the generally cylindrical body portion  46  and define a groove  53  therebetween. As seen in FIG. 3, an O-ring  55  is seated between the ridges  52  in the groove  53 . The O-ring  55  is preferably made of silicone but may be made of any suitable material. The generally cylindrical body portion  46  of the rotor  14  terminates in a generally planar intermediate surface  56  best shown in FIG.  9 . 
     The rotor  14  also has a generally cylindrical stem portion  58  having an outer surface  60 . This stem portion  58  extends outwardly from the generally cylindrical body portion  46 , and more particularly from the intermediate surface  56  of the generally cylindrical body portion  46 . As best illustrated in FIG. 3, the stem portion  58  of the rotor  14  extends through an opening  62  in the removable cover  31  of the rotor valve housing  12 . An O-ring  64  is located in the removable cover  31  of the rotor valve housing  12 . See FIG.  3 . The rotor  14  rotates about an axis A due to bearings  65 . See FIG. 3. A rotor shaft  66  is secured to the stem portion  58  of the rotor  14 . Any suitable drive mechanism (not shown) may be coupled to the rotor shaft  66  in any conventional manner known to those skilled in the art in order to rotate the rotor  14 . 
     Additionally an air cylinder or other lifting mechanism (not shown) may be used to lift or move the rotor  14  during the cleaning process in the direction of arrow  4  without having to disassemble the filler  10  as will be described below. See FIG.  1 . The air cylinder or lifting mechanism (not shown) also exerts pressure on the rotor shaft  66  in order to maintain a zero-clearance seal between the outer surface  48  of the generally conical sealing end portion  44  of the rotor  14  and the generally conically-shaped seating surface  38  of the rotor valve housing  12 . When the rotor  14  is in its lowered position shown in FIG. 3, the O-ring  55  forms a seal with a contact portion  105  of the body  22  of the housing  12 , thereby preventing product from entering an upper portion  5  of the cavity  30  of the housing  12 . 
     As best illustrated in FIG. 6, the rotor  14  has a filling slot or channel  68  therein which extends inwardly from the outer surface  15  of the rotor  14 . This filling slot or channel  68  has a bottom surface  70  and a sidewall surface  72  as best illustrated in FIG.  6 . This filling slot, channel or passage  68  allows product P to flow through product supply pipe  20 , through the conduit  40  of the rotor valve housing  12  into the interior of the cylinder  18  in a manner described below. 
     The rotor  14  also has a second passage  74  therethrough, referred hereinafter as internal passage  74 . See FIGS. 5-9. As shown in FIG. 6, the internal passage  74  through the rotor  14  comprises two openings  76  at the ends thereof in the outer surface  48  of the end portion  44  of the rotor  14 . 
     The rotor  14  is rotatable between a first or prime position illustrated in FIG. 4 and a second or fill position illustrated in FIG. 5 by the rotor drive mechanism (not shown). Referring to FIG. 4, in the first or prime position, product P may flow in the direction of arrow  78  through product supply pipe  20 , through the conduit  40  of the rotor valve housing  12 , out the metering cylinder port  34  and into the interior of the cylinder  18  as the piston  16  moves from left to right. Referring to FIG. 5, in the second or fill position, product P may flow in the direction of arrow  80  from the interior of the cylinder  18 , through the metering cylinder port  34 , through the internal passage  74  of the rotor, out the product discharge port  36  of the rotor valve housing  12  and into a container C located therebelow as the piston  16  moves from right to left. 
     As best illustrated in FIGS. 3-5, the product metering cylinder or chamber  18  has a wall  82  having an inner surface  84  and an outer surface  86 . The inner surface  84  of the cylinder wall  18  defines an interior  92  of the cylinder  18  having a longitudinal axis  94 . At one end the cylinder  18  is joined to the rotor valve housing  12  and at the other end is supported by a cylinder end cap  88 . Four tie rods  90  secure the cylinder end cap  88  to the rotor valve housing  12 . 
     Inside the interior  92  of the cylinder  18  the piston  16  moves laterally along the length of the cylinder  18 . As shown in FIG. 3, the piston  16  has a piston head  96  and a piston rod  98  secured to the piston head  96  in any conventional manner. The piston  16  is moved back and forth in the interior  92  of the cylinder  18  by a piston drive mechanism (not shown) in the direction of arrows  100 . FIGS. 3 and 4 illustrate the piston in a first position in which no product P may enter the interior  92  of the cylinder  18  through the metering cylinder port  34  due to the location of the piston and more particularly, the location of the piston head  96 . FIG. 5 illustrates the piston  16  in a second position in which product P has entered a portion  102  of the interior  92  of the cylinder  18  through the metering cylinder port  34  due to the location of the piston and more particularly, the piston head  96 . As the piston drive mechanism (not shown) pulls the piston  16  to the right in the drawings, product P is drawn into the portion  102  of the interior  92  of the cylinder  18  through the metering cylinder port  34 . 
     When the rotor  14  is in either the first or second position, the outer surface  48  of the generally conical sealing end portion  44  of the rotor  14  is in contact with the generally conically-shaped seating surface  38  of the rotor valve housing  12 . This contact creates a zero-clearance seal therebetween which prevents product from leaking back into the interior  92  of the cylinder  18  through the metering cylinder port  34  or leak through the product discharge port  36  into the container. Thus, the zero-clearance seal between the outer surface  48  of the generally conical sealing end portion  44  of the rotor  14  and the generally conically-shaped seating surface  38  of the rotor valve housing  12  ensures that the container C is filled with the proper amount of fill, not too much or too little. 
     As shown in FIGS. 4 and 5, the filling process begins by introducing product P into the filler  10  through product supply pipe  20 . 
     Prior to a container C arriving at the filling station, the rotor  14  is positioned in the rotor valve housing  12  in its first or prime position illustrated in FIG.  3 . In this position its internal passage  74  is sealed closed and its filling slot or channel  68  is open to both the product supply P and the interior  92  of the product metering cylinder  18  through cylinder port  34 . When the rotor  14  is in this first or prime position, the piston  16  is pulled back (to the right in FIG.  4 ), drawing product P from the product supply (not shown), through product supply pipe  20 , through the conduit  40  of the rotor valve housing  12 , through the filling slot  68  of the rotor  14 , out the metering cylinder port  34  of the rotor valve housing  12  and into the interior  92  of the cylinder  18 . The amount of product to be filled into the container C is determined by the length of the stroke of the piston  16 . A short stroke of the piston  16  allows less product into the interior  92  of the product metering cylinder  18 , while a longer stroke allows more product to be filled into a container C. 
     When a container C arrives at the filling position, a control circuit energizes a suitable rotor drive mechanism (not shown) which is attached to the rotor shaft  66  and rotates the shaft and the rotor  14  into its second or fill position illustrated in FIG.  5 . In this position, the internal passage  74  of rotor  14  is aligned with both the product metering cylinder port  34  and with the spout or product discharge port  36  above the container C. When the rotor  14  is in this second or fill position illustrated in FIG. 5, the filling slot or channel  68 , however, is now sealed off from both the product metering cylinder port  34  and with the spout or product discharge port  36  above the container C. A control circuit then initiates the motion of the product piston  16  forward toward the housing  12  (to the left in FIG.  5 ). As the product piston  16  moves forward toward the housing  12 , it pushes product P out of the interior  92  of the product cylinder  18 , through the product metering cylinder port  34 , through the rotor&#39;s internal passage  74 , through product discharge port  36  and into container C. When the product piston  16  reaches the farthest forward position, the interior  92  of the product metering cylinder  18  is emptied and the motion of the piston stops. 
     After the product piston  16  completes the forward stroke, the control circuit de-energizes a solenoid valve (not shown) which rotates the rotor shaft  66  and the rotor  14  back into its first or prime position illustrated in FIG.  4 . When the product piston  16  moves backward away from the housing  12 , fresh product is drawn into the interior  92  of the product cylinder  18 , ready for the next fill cycle. 
     The filler  10  of the present invention is specifically designed to enable the filler  10  to be cleaned with a cleaning solution or fluid without disassembling the filler  10 . The cleaning process is similar to the filling process in that any suitable cleaning solution may be supplied through the product supply pipe  20  and pass through the same passages as the product, the rotor  14  and piston  16  operating in the same fashion. During cleaning, rotor  14  can be reciprocated axially in bore or cavity  30  of rotor housing  12 , so that its outer conical surface  48  is reciprocated toward and away from complimentary surface  38  of the cavity  30  of the housing  12 . The cleaning solution is not filled into containers, but is ejected through product discharge port  34  and collected in a drain trough located below the spouts and recirculated back into the filler. 
     In addition to the simulated filling action, the rotor  14  raises and lowers axially (see arrow  4 ) to allow cleaning solution to flow onto a gap  104 , best illustrated in FIG.  3 . The gap  104  exists between the outer surface  54  of the body portion  46  of the rotor  14  and the complimentary side surface  37  of the cavity  30  the housing  12 . More particularly, as the rotor  14  is raised from a lowered or non-cleaning position shown in the figures to a raised or cleaning position, the O-ring  55  seated in the groove  53  is raised above a contact portion  105  of the body  22  of the housing  12  and the outer surface  48  of the generally conical sealing end portion  44  of the rotor  14  is raised off the generally conically-shaped seating surface  38  of the rotor valve housing  12 , thereby breaking the zero-clearance seal. See FIG.  3 . When the rotor  14  is in its lowered or non-cleaning position, the O-ring  55  forms a zero clearance seal between itself and the contact portion  105  of the body  22  of the housing  12 , thereby preventing cleaning fluid from passing into the gap  104  between the outer surface  15  of the rotor and the body  22  of the housing  12 . In addition, when the rotor  14  is in its lowered or non-cleaning position the outer surface  48  of the generally conical sealing end portion  44  of the rotor  14  contacts the generally conically-shaped seating surface  38  of the rotor valve housing  12 , thereby creating a zero-clearance seal. When the rotor  14  is in its raised or cleaning position the O-ring  55  does not contact the contact portion  105  of the body  22  of the housing  12 , thereby breaking the zero clearance seal and allowing cleaning fluid to enter the gap  104  between the outer surface  15  of the rotor and the body  22  of the housing  12  for cleaning purposes. With the rotor  14  in this raised position, the O-ring  55  is located in an upper portion  5  of the cavity  30  of the housing  12  which has a larger diameter than the portion of the cavity  30  proximate the contact portion  105  of the body  22 . Therefore, when cleaning fluid (CF) is introduced into the upper portion  5  of the cavity  30  of the housing via spout  6  extending upwardly from the removable cover  29  of the housing  12 , cleaning fluid may flow into the gap  104  to clean the exposed surfaces of the rotor  14  and the exposed surfaces of the housing  12 . In addition, cleaning fluid may flow between the outer surface  48  of the generally conical sealing end portion  44  of the rotor  14  and the generally conically-shaped seating surface  38  of the rotor valve housing  12 . 
     At the initiation of the cleaning process, the rotor  14  is raised to its raised, cleaning position as described above. Additionally, the piston  16  is moved away from the housing  12  (moved to the right in FIG. 3) so that cleaning fluid may be introduced through a spout  7  extending upwardly from the product metering cylinder  18  inside the piston head  96 . With the piston  16  is this position, cleaning fluid or solution CF may be introduced through the spout  7  into the interior  92  of the metering cylinder  18  for cleaning purposes. Movement of the piston  16  enhances the cleaning process in a manner described below. 
     As shown in FIG. 3A, the piston  16  has an outer surface  106  in which is cut an O-ring groove  108 . Inside the O-ring groove  108  reside a silicone O-ring  110  having a generally oval shape. Outside the O-ring  110  is a ultra high molecular weight polyethylene sealing ring  112  having an outer surface  114  in contact with the inner surface  84  of the cylinder wall  82  and an inner surface  116  in contact with the O-ring  110 . The polyethylene ring  112  has a width W 1  slightly shorter than the width W 2  of the O-ring groove  108  in order to allow cleaning fluid or cleaning solution to clean the interior of the O-ring groove  108  including the exterior surface of the O-ring  110 . During the cleaning process, cleaning fluid flows through a gap  118  between the outer surface  106  of the piston  16 , more particularly the outer surface of the piston head  96  and the inner surface  84  of the cylinder wall  82 . The location and operation of the ultra high molecular weight polyethylene ring  112  prevents direct contact between the O-ring  110  and the inner surface  84  of the metering cylinder wall  82 , which prolongs the useful life of the O-ring  110 . Due to the high temperature of the cleaning solution, direct contact between an O-ring and the inner surface of a metering cylinder wall may damage the O-ring as the piston moves. The present invention eliminates this possibility by providing a sealing ring  112  between the O-ring and the inner surface  84  of the metering cylinder wall  82 . 
     The rotor housing  12  and metering cylinder  18  can be configured to different sizes to match fill size requirements and the product characteristics such as particulates in the product. Also, multiple fillers can be attached together with a common drive source for multiple fills at once. 
     Different spouts can be attached to the discharge port of the housing  12  to suit different products. For example, a “shower head” style spout can be added to reduce foaming and splashing with low viscosity products. 
     Different supply piping systems can be used with the filler. A pressurized system in conjunction with a compensator can be used for products that have steady flow requirements, such as margarine and ice cream. A non-pressurized hopper system can be used for a wide variety of products. 
     The zero clearance rotor valve can also be used in a two-way valve for other types of filling. The rotor and rotor housing can be configured to simply open and close the discharge port to a supply source. The fill size can then be controlled by means of a steady state flow and timed on/off signals, on/off signals from a flow meter, on/of signals from a weigh scale under the container, etc. The rotor and housing would still provide all of the advantages listed above. 
     Although the rotor  14  and rotor housing  12  along with all the other components of the present invention are preferably made of stainless steel, any one of the components of the filler  10  may be made of other materials. 
     These and other alterations and modifications will become readily apparent to those of ordinary skill in the art without departing from the scope of the invention and applicant intends to be bound only by the claims appended hereto.