Cyclically weighing bulk solid material

In a method for cyclically weighing flowable bulk solid material as part of a dispensing process comprising the steps of:

• supplying said material from a continuously operating controllable delivery feed arrangement to a weigh-pan,
• generating a signal indicative of the amount of material in the weigh-pan,
• terminating supply of said material from said feed arrangement when said signal indicates a predetermined amount of material in the weigh-pan,
• causing the weigh-pan, after receiving and weighing all the material supplied by said feed arrangement up to the said termination of said supply, to deliver its contents, and
• preparing the weigh-pan for the next cycle, the improvement comprising:
• predetermining a rate of delivery from said weigh-pan in accordance with the requirements of said dispensing process in terms of the average amount delivered per cycle and the cycle frequency,
• supplying from said feed arrangement material to said weigh-pan through valve means in which said material accumulates when said weigh-pan is not receiving material from said valve means,
• controlling said controllable feed arrangement to supply said material substantially at said predetermined rate;
• inhibiting, during an early part of the cycle, termination of the supply of said material from said feed arrangement on said signal indicating a predetermined amount of material in the weigh-pan, whereby to avoid said termination of the predetermined weight being prematurely registered on account of the inertia of the initial supply dropped from the feed arrangement;
• and
• producing a rate-of-fill signal by producing the time-derivative of the weight of said weigh-pan during a cycle, and cancelling the inhibition of said termination of the supply of said material to the weigh-pan when said time-derivative becomes zero.

In a method for cyclically weighing flowable bulk solid material as part of a dispensing process comprising the steps of:

• supplying said material from a continuously operating controllable delivery feed arrangement to a weigh-pan,
• generating a signal indicative of the amount of material in the weigh-pan,
• terminating supply of said material from said feed arrangement when said signal indicates a predetermined amount of material in the weigh-pan,
• causing the weigh-pan, after receiving and weighing all the material supplied by said feed arrangement up to the said termination of said supply, to deliver its contents, and
• preparing the weigh-pan for the next cycle, the improvement comprising:
• predetermining a rate of delivery from said weigh-pan in accordance with the requirements of said dispensing process in terms of the average amount delivered per cycle and the cycle frequency,
• supplying from said feed arrangement material to said weigh-pan through valve means in which said material accumulates when said weigh-pan is not receiving material from said valve means,
• controlling said controllable feed arrangement to supply said material substantially at said predetermined rate;
• and
• producing a rate-of-fill signal by producing the time-derivative of the increasing weight of said weigh-pan during a cycle, and controlling said controllable feed arrangement in accordance with said rate-of-fill signal.

In an apparatus for cyclically weighing flowable bulk solid material as part of a dispensing arrangement, comprising:

• a continuously operating, controllable delivery feed arrangement,
• a weigh-pan receiving material from said feed arrangement,
• control means comprising:
• a signal generator indicative of the amount of material in the weigh-pan,
• supply terminating means operative to terminate supply of said material from said feed arrangement when said signal generator indicates a predetermined amount of material in the weigh-pan, and
• delivery control means operative to cause the weigh-pan, after receiving and weighing all the material supplied by said feed arrangement up to the said termination of said supply, to deliver its contents and to prepare the weigh-pan for the next cycle, the improvement comprising:
• valve means in said controllable feed arrangement for controlling the supply of said material to said weigh-pan, in which said material can accumulate when said weigh-pan is not receiving material from said valve means,
• said control means further comprising means for controlling said controllable feed arrangement.

In an apparatus for cyclically weighing flowable bulk solid material as a part of a dispensing arrangement, comprising:

• a continuously operating, controllable delivery feed arrangement,
• a weigh-pan receiving material from said feed arrangement,
• control means comprising:
• a signal generator indicative of the amount of
• material in the weigh-pan,
• supply terminating means operative to terminate supply of said material from said feed arrangement when said signal generator indicates a predetermined amount of material in the weigh-pan, and
• delivery control means operative to cause the weigh-pan, after receiving and weighing all the material supplied by said feed arrangement up to the said termination of said supply, to deliver its contents and to prepare the weigh-pan for the next cycle, the improvement comprising:
• valve means in said controllable feed arrangement for controlling the supply of said material to said weigh-pan, in which said material can accumulate when said weigh-pan is not receiving material from said valve means,
• said control means further comprising means for controlling said controllable feed arrangement;
• and
• differentiating means for producing a rate-of-fill signal for said weigh-pan.

In an apparatus for cyclically weighing flowable bulk solid material as part of a dispensing arrangement, comprising:

• a continuously operating, controllable delivery feed arrangement,
• a weigh-pan receiving material from said feed arrangement,
• control means comprising:
• a signal generator indicative of the amount of material in the weigh-pan,
• supply terminating means operative to terminate supply of said material from said feed arrangement when said signal generator indicates a predetermined amount of material in the weigh-pan, and
• delivery control means operative to cause the weigh-pan, after receiving and weighing all the material supplied by said feed arrangement up to the said termination of said supply, to deliver its contents and to prepare the weigh-pan for the next cycle, the improvement comprising:
• valve means in said controllable feed arrangement for controlling the supply of said material to said weigh-pan, in which said material can accumulate when said weigh-pan is not receiving material from said valve means,
• said control means further comprising means for controlling said controllable feed arrangement;
• inhibiting means inhibiting, during an early part of the cycle, termination of the supply of said material from said feed arrangement on said signal generator indicating a predetermined amount of material in the weigh-pan;
• and
• differentiating means for producing a rate-of-fill signal for said weigh-pan and zero-rate-of-fill detection means controlling said inhibiting means to cancel the inhibiting effect thereof on detection of a zero-time-derivative.