Device for metering and entraining a product into a gas stream

In a conveying system for intermittently conveying a dry, solid particulate product through a conduit system interconnecting a product supply container to a desired destination, the conduit system having a gas inlet end for facilitating the entry of a gas stream into the conduit system and a gas outlet end for facilitating the exit of the gas stream from the conduit system, and a gas pumping means for pumping the gas stream through the conduit system, the improvement comprising an intermittently operated device for metering and entraining a measured quantity of the product with a gas stream moving in the conduit system, said device including:

• an enlarged hollow housing having first means defining a gas inlet opening to an interior of said enlarged housing that is smaller in cross sectional area than the cross sectional area of said housing and connected in fluid communication with the gas inlet end, and second means defining a gas and product outlet opening from the interior of said enlarged housing, said gas inlet opening and said gas and product outlet opening being series connected to the conduit system so that all of a gas stream must enter said enlarged housing through said gas inlet opening in order to get from the gas inlet opening to said gas and product outlet opening;
• third means defining a product receiving opening into said interior of said housing intermediate said gas inlet opening and said gas and product outlet opening, said gas inlet opening including inlet means for causing the gas stream to move between said gas inlet opening and said gas and product outlet opening through said interior of said housing and beneath said product receiving opening at a sufficient pick-up velocity to pick up and entrain product entering said interior of said housing in the gas stream;
• connection means for facilitating a connection of said product receiving opening to the product supply container to facilitate a supply of the product to said interior of said housing through said product receiving opening;
• normally closed gate means within said housing, and drive means for moving said gate means between a closed position blocking said product receiving opening to the interior of said housing and an opened position spaced from said product receiving opening for allowing the product to enter the interior of said housing;
• control means for intermittently operating said drive means and said gate means to said opened position for a selected interval of time;
• and
• adjustment means for facilitating an adjustment of the spacing between said gate means and said product receiving opening to a set dimension that said gate means always moves to when said gate means is in said opened position to facilitate a controlled metering of the volume of product entering the interior of said housing, the gas stream entering said gas inlet opening picking up and entraining the product therein and exiting said housing through said gas and product outlet opening, said control means effecting a movement of said gate means to said closed position thereof at an end of said selected interval of time to halt the supply of product to said interior of said housing while said gas pumping means continues operating to enable the gas stream to purge the housing and the conduit system of product between said housing and the desired location.