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Weight Loss Patent Abstract
A system is disclosed that minimizes the effect of internal pressure
upon weight-loss weighing systems. The system can include a flexible
gas purge line that pressurizes the system as well as a pressure
compensator that negates the adverse effects of internal pressure
on weight sensing equipment during normal operation.
Weight Loss Patent Claims
1. A weight-loss weigh feeder system comprising: a scale; a container
attached to the scale, the container having at least one material
inlet for filling a material supply and at least one flexible gas
impermeable connector between the container and the at least one
material inlet; a flexible gas inlet connected to the container;
and a metering mechanism, to discharge the material supply from
the container, wherein the scale provides a signal indicative of
a weight associated with the material supply in the container.
2. The weight-loss weigh feeder system of claim 1 wherein the gas
inlet is attached to any location on the container.
3. The weight-loss weigh feeder system of claim 1 comprising a
pressure compensator attached to the container, the pressure compensator
configured to provide internal pressure compensation in the container
when a pressurized gas is present in the container.
4. The weight-loss weigh feeder system of claim 3 wherein the gas
inlet is attached to any location on the pressure-compensator.
5. The weight-loss weigh feeder system of claim 3 wherein the pressure
compensator is attached to any location on the container which is
exposed to the inside of the container.
6. The weight-loss weigh feeder system of claim 3 wherein the pressure
compensator comprises an annular ring.
7. The weight-loss weigh feeder system of claim 3 wherein the pressure
compensator comprises a lower conical portion to direct product
into the container.
8. The weight-loss weigh feeder system of claim 3 wherein the pressure
compensator provides accurate weighing of the material supply by
the scale when pressurized gas is present in the container.
9. The weight-loss weigh feeder system of claim 1 comprising a
vent connection on the container, the vent connection attached to
a flexible gas impermeable connector to allow disbursement of displaced
gas in the container when a pressurized gas enters the gas inlet.
10. The weight-loss weigh feeder system of claim 1 wherein the
at least one material inlet comprises a closable valve, the valve
flexibly connected to the container and openable to allow a flow
of the material supply to enter the container.
11. A method of weighing material on a weight-loss basis comprising:
providing a material supply into a container through at least one
material inlet, the at least one material inlet providing a passage
for the material supply entering the container; pressurizing the
container by passing gas through a flexible gas inlet having a gas-impermeable
flexible conduit and allowing the gas to contact a pressure compensator,
the pressure compensator reducing or eliminating an unequal pressurized
force in the container; and metering at least a portion of the material
supply from the container.
12. The method of claim 11 wherein the pressure compensator comprises
an annular ring.
13. A method of metering material on a weight-loss basis comprising:
disposing a container and a metering mechanism on a scale; providing
the container with a material supply; pressurizing the container
with a gas using a flexible gas inlet; weighing the material supply
in the container while using a pressure compensator, the pressure
compensator reducing or eliminating an unequal pressurized force
in the container; and metering a portion of the material supply
from the container.
14. The method of claim 13 wherein the pressure compensator comprises
an annular ring providing internal pressure compensation in the
container when pressurized gas enters the container.
15. A method of weighing material under internal pressure comprising:
providing material into a container, the container having a material
inlet to provide a path for the material to enter the container
and a gas inlet having a gas-impermeable flexible conduit for gas
to enter the container; and weighing the material in the container
while using a pressure compensator, the pressure compensator having
an annular ring for minimizing or negating unequal pressurized force
in the container.
Weight Loss Patent Description
TECHNICAL FIELD
[0001] This disclosure relates to a weight-loss weigh feeder using
pressure compensation.
BACKGROUND
[0002] Weight-loss weigh feeders are used to meter dry and liquid
ingredients, at specific feed rates, either on a continuous or batch
basis, into a wide range of processes. In many applications, weight-loss
weigh feeders can be used to proportion various ingredients that
comprise a particular formulation (e.g, foods, plastics, chemicals,
pharmaceuticals, etc.).
[0003] Generally, weight-loss weigh feeders include a vessel (e.g.,
a hopper or tank appropriately designed and sized for specific ingredients
and/or applications) mounted onto a weighing system (e.g., a scale)
where product discharge is regulated based on a desired discharge
or feed rate (i.e., weight output vs. time).
[0004] Typically, product is discharged out of the vessel by applying
a metering device. The loss of weight, as sensed by the weighing
system, can be transmitted to the feeder's controller and calculated
into a feed rate (e.g., pounds or tons per minute or hour). The
controller then can compare the calculated rate of discharge to
a desired (set) discharge rate and simultaneously modulate the output
of the weigh feeder's metering device to maintain the desired (set)
rate.
[0005] Weight-loss weigh feeders require the weigh vessel be periodically
refilled with product. In some applications, the weight-loss weigh
feeder also may need to operate under the presence of dry air, or
a gas purge (e.g., nitrogen, helium, argon) to prevent the material
being handled from being exposed to potentially adverse reactants,
such as ambient air. Generally, these applications require internal
areas of the weight-loss weigh feeder to operate in the presence
of some pressurized inert gas that forces out ambient air from within
the feeder, and/or precludes ambient air from entering the feeder.
The introduction of internal pressure in the vessel (whether constant
or fluctuating), however, can create forces upon the weighing system
that adversely affect accurate performance during normal operation.
SUMMARY OF THE DISCLOSURE
[0006] A system is disclosed that minimizes the effect of internal
pressure upon weight-loss weighing systems. The system can include
a gas inlet flexibly connected to a container and a pressure compensator
that negates the adverse effects of internal pressurization (positive
or negative) upon the weighing system during normal operation.
[0007] For example, according to one aspect, a system includes
a container attached to a scale, the container having at least one
material inlet for adding a material supply (product) and at least
one flexible gas impermeable connector connected to the container
that is capable of pressurizing the container, and a metering mechanism
for removing material supply from the container.
[0008] In some implementations, the system also can include a pressure
compensator attached to the container. The pressure compensator
is configured to affect the adverse effects upon weight sensing
when either a pressurized gas enters the container or a vacuum condition
exists in the container.
[0009] In another aspect, a method includes providing a material
supply or product into a container through at least one material
inlet, the at least one material inlet providing a path or passage
for the material supply or product entering the container. The method
may either pressurize or depressurize the container by passing gas
through a flexible gas inlet having a gas-impermeable flexible conduit
and allowing the gas to contact a pressure compensator, the pressure
compensator reducing an unequal pressurized force in the container,
and metering at least a portion of the material supply from the
container.
[0010] According to another aspect, a method includes providing
material into a container, the container having a material inlet
to provide a path for the material to enter the container and a
gas inlet having a gas-impermeable flexible conduit for gas to enter
the container. The method includes weighing the material in the
container which has attached to it a pressure compensator that has
an annular ring for minimizing unequal pressurized force in the
container.
[0011] In some implementations, one or more of the following advantages
can be present. For example, the pressure compensator can minimize
or eliminate the adverse effects of internal pressure (positive
or negative) from affecting accurate weight sensing. This may be
particularly advantageous in optimizing system performance and cost
effectiveness.
[0012] Another benefit may relate to container venting. Container
venting may be accomplished by using a vent valve which opens and
closes.
[0013] A further benefit may relate to sizing of the system components.
The components of the pressure compensator would be sized as needed
so that internal pressure in the container is equalized, thereby
leaving the system to operate in a normal fashion.
[0014] An additional benefit may relate to the system's flexible
gas line. The flexible gas line delivers purge gas to the interior
of the container and has no positive or negative influence on the
scale. The system also utilizes flexible sleeve material that allows
free scale movement, but is gas impermeable so the purge gas can
be contained in the container and not escape into the surrounding
environment.
[0015] Additional features and advantages will be readily apparent
from the following detailed description, the accompanying drawings
and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 illustrates an example of a weight-loss weigh feeder
system with pressure compensation.
[0017] FIG. 2 illustrates an example of pressure forces applied
to the weight-loss weigh feeder system of FIG. 1.
[0018] Like reference symbols in the various drawings indicate
like elements.
DETAILED DESCRIPTION
[0019] FIG. 1 discloses an example of a weight-loss weigh feeder
system 100 that operates in the presence of internal pressure. The
weight-loss weigh feeder system 100 may be installed as part of
a contained materials-handling system that can be sealed for dust
containment.
[0020] As shown in the FIG. 1 example, the system 100 includes
a flexible gas purge line 140 that provides gas pressurization of
a container (e.g., vessel, hopper, or tank) 110 capable of accommodating
product supply. The flexible gas purge line 140 can be located anywhere
on an upper portion of the system 100, the container 110, or the
lower conical portion 122 of the pressure-compensator 121. The container
110 is affixed to a scale 130. The system 100 includes a metering
mechanism 101 that provides discharge of product from the container
110.
[0021] The system 100 includes a pressure-compensator 121 that
is affixed to the scale. The pressure-compensator 121 operates to
minimize or eliminate the effect of internal pressure in the container
110 on the scale 130 during weight sensing operations. For example,
when pressure in the container is present, the pressure-compensator
121 operates to equalize internal pressure forces exerted on the
scale 130 and thereby minimizes or eliminates inaccurate weighing
of product supply in container 110 that can occur otherwise.
[0022] A product-supply inlet 102 and a vent connection 106 are
provided and allow internal pressure in the container to extend
out to fixed surfaces 104, 108 respectively. Fixed surfaces 104,
108 are off the scale. The product-supply inlet 102 is attached
to a product-refill mechanism 180 that typically includes an actuator
112 and a product-supply inlet valve 181. A vent shut-off valve
115 and a vent shut-off valve actuator 114 are located adjacent
to the pressure-compensator 121. Actuator 114 acts to move valve
115 between an open position and a closed position. The product-refill
mechanism 180 and vent valve actuator 114 cooperate together to
provide for adding product in the container 110 when the product
reaches a low level. For example, in one embodiment, when a certain
amount of product needs to be added to refill the container 110,
the vent shut-off valve 115 opens to allow venting of gas from the
container 110. The actuator 112 then activates, valve 181 opens,
and product is added to the container 110 at inlet 102. Once a desired
amount of material supply or product is loaded into the container
110, the product-supply inlet valve 181 closes, and then vent shut-off
valve 115 closes. Inert or other gas can be added via flexible gas
purge line 140 to reestablish purge pressurization of the container
110.
[0023] The product-refill mechanism 180 is mounted to a fixed surface
104 and is flexibly connected to the product-supply inlet 102 located
on a cover 120 of the container 110 via flexible sleeve 131. The
vent valve actuator 114 and vent shut-off valve 115 are mounted
to a fixed surface 108. The vent connection 106 can be connected
to a dust collection or exhaust system. In one implementation, as
shown in the FIG. 1 example, the vent valve actuator 114 is attached
to the vent shut-off valve 115. The vent shut-off valve 115 eliminates
any potentially adverse effects of a vacuum draw (negative draw)
on the container 110 that can be caused by a dust collection system.
[0024] The vent connection 106 may be used to extract dust and
displaced air from the container 110 when the container 110 is refilled
with product through the product-supply inlet 102. As shown in the
FIG. 1 example, the vent connection 106 extends through the pressure-compensator
121, which includes a conical lower portion 122 to direct product
that may settle out of dust laden displaced air or other gas back
into the container 110. In one implementation, the conical lower
portion 122 of the pressure-compensator 121 is independently supported
off the container 110.
[0025] Once pressurization of the container 110 occurs, equal and
opposite forces generated by pressure internal to the container
110 act against internal surfaces of the container 110 uniformly.
The upward component of force, which acts uniformly across the face
of the container cover 120, extends through the product-supply inlet
102 and vent connection 106 onto the fixed surfaces 104, 108. Due
to the product-supply inlet 102 and vent connection 106 penetrations
in the container cover 120, the surface area of the container cover
120 is not equal to that of the surfaces directly opposite the container
cover, e.g., at areas 116, 118. Therefore, the upward component
of force acting against the container cover 120 is less than the
opposite downward component of force acting on the bottom of container
110.
[0026] The pressure-compensator 121 includes an annular compensation
ring 124, sized such that the surface area of the ring is identical
to the sum of the cross sectional areas of the system's product-supply
inlet 102 and vent connection 106. The compensation ring 124 operates
to equalize the before-mentioned forces. One advantage of the compensation
ring 124 is that it may minimize or negate the adverse effects of
internal pressure (positive or negative) from affecting accurate
weight sensing and, in turn, system performance. In some implementations,
the pressure-compensator 121 is arranged as a pressure-balancing
mechanism to ensure accurate weight sensing by scale 130 in the
presence of an internal (purge) pressure.
[0027] FIG. 2 illustrates an example of pressure forces applied
to the example weight-loss weigh feeder system of FIG. 1. As explained
previously, in one implementation, the pressure-compensator 121
is located in the vent connection 106 and has the conical lower
portion 122 that directs the return of accumulated product back
into the container 110 (i.e., dust that rises upward) while venting
during a product refill operation.
[0028] Example forces acting on the weigh feeder system due to
pressurization are illustrated as arrows in FIG. 2. Positive forces
that add (erroneously) to the weight measurement of product within
the container 110 are illustrated with a "+" symbol. Negative
forces that subtract from the weight measurement of product are
illustrated with a "-" symbol. These negative forces counterbalance
the positive forces mentioned previously. Static forces that neither
add nor subtract weight have no symbol.
[0029] The flexible gas purge line 140 provides purge gas to the
interior of the container 110, but itself has no positive or negative
influence on the scale 130. Flexible connectors or sleeves 131,
131a, 131b and 131c are provided to allow free movement of the weighing
system in response to changes of weight (e.g., material) within
the container 110, and are gas impermeable. Thus, the purge gas
contained within the container 110 can not escape into the surrounding
atmosphere and the flexible sleeves can create an airtight system
when valves 181 and 115 are closed. The compensation ring 124 of
the pressure-compensator 121 is attached directly to the container
cover 120 of the container 110 by elements 121. The compensation
ring 124 is exposed to the contents of container 110 and may be
attached to any location on the container cover 120. During pressurization,
the internal purge pressure imparts an upward force on the compensation
ring 124 equal to the downward force on the opposite portions of
container 110 at locations 116, 117, 118 and 119. Since the compensation
ring 124 is mounted to the container 110 of the system 100 by attachment
to cover 120, the upward force on ring 124 is transferred directly
to the container 110. The conical lower portion 122 of the pressure-compensator
121 is supported off the scale 130. The compensation ring 124 can
continuously negate any adverse effects that pressure (internal
to the container) would have upon weight sensing, and system performance.
[0030] Other implementations are within the scope of the following
claims. |