Apparatus and method for mixing a plurality of substances

An apparatus for controlling the mixing of a plurality of substances, comprising:

• portable support means for being transported;
• a holding tank mounted on said support means;
• first container means, mounted on said support means, for holding a first additive;
• second container means, mounted on said support means, for holding a second additive;
• inlet conduit means, mounted on said support means, for providing a flow path to said holding tank;
• outlet conduit means, mounted on said support means, for providing a flow path from said holding tank;
• first connector means, mounted on said support means, for providing a flow path from said first container means to said inlet conduit means, said first connector means including first pump means for pumping said first additive from said first container means to said inlet conduit means, said first pump means including:
• a first pump having an inlet connected to said first container means and having an outlet connected to said inlet conduit means;
• and
• first drive means for driving said first pump;
• second connector means, mounted on said support means, for providing a flow path from said second container means, said second connector means including second pump means for pumping said second additive from said second container means, said second pump means including:
• a second pump having an inlet connected to said second container means;
• and
• second drive means for driving said second pump;
• and
• control means, for controlling, in response to a flow along said inlet conduit means, the flow of said first additive from said first container means into said inlet conduit means and for controlling, in response to a flow along said outlet conduit means, the flow of said second additive from said second container means for mixing with a flow including said first additive, said control means including:
• first detector means for providing a first electrical signal proportional to a speed at which said first drive means drives said first pump;
• second detector means for providing a second electrical signal proportional to a speed at which said second drive means drives said second pump;
• third detector means for providing a third electrical signal proportional to a rate at which a fluid flows through said inlet conduit means;
• fourth detector means for providing a fourth electrical signal proportional to a rate at which a mixture including said fluid and said first additive flows through said outlet conduit means;
• first digital means, responsive to said first and third electrical signals, for providing a first control signal for controlling said first drive means;
• and
• second digital means, responsive to said second and fourth electrical signals, for providing a second control signal for controlling said second drive means.

An apparatus for producing a well fracturing substance utilizing water from a water source and a liquid gel concentrate from a liquid gel concentrate source and further utilizing a blender tub having an inlet line and an outlet line, said outlet line being connectible to a well, said apparatus comprising:

• a holding tank;
• inlet conduit means for connecting said water source to said holding tank;
• first connector means for connecting said liquid gel concentrate source to said inlet conduit means, said first connector means including first pump means for pumping said liquid gel concentrate from said liquid gel concentrate source to said inlet conduit means;
• first additive container means for containing an additive including a buffering agent;
• second connector means for connecting said first additive container means to said inlet conduit means, said second connector means including second pump means for pumping said buffering agent from said first additive container means to said inlet conduit means;
• third pump means, disposed in said inlet conduit means, for pumping a mixture of said water, said liquid gel concentrate and said buffering agent into said holding tank;
• outlet conduit means for connecting said holding tank to said blender tub;
• second additive container means for containing an additional additive;
• third connector means for connecting said second additive container means to said outlet line of said blender tub, said third connector means including fourth pump means for pumping said additional additive from said second additive container means to said outlet line of said blender tub;
• and
• control means for controlling said first, second and fourth pump means to pump said liquid gel concentrate and said buffering agent into said inlet conduit means and said additional additive into said outlet line of said blender in preselected proportions, said control means including:
• first flow rate detector means for detecting a flow rate of said water flowing through said inlet conduit means;
• second flow rate detector means for detecting a flow rate of said liquid gel concentrate flowing through said first connector means;
• third flow rate detector means for detecting a flow rate of said buffering agent flowing through said second connector means;
• fourth flow rate detector means for detecting a flow rate of said mixture flowing through said outlet conduit means;
• fifth flow rate detector means for detecting a flow rate of said additional additive flowing through said third connector means;
• first speed detector means for detecting a speed at which said first pump means operates;
• second speed detector means for detecting a speed at which said second pump means operates;
• third speed detector means for detecting a speed at which said fourth pump means operates;
• concentration setting means for setting a liquid gel concentrate concentration value, a buffering agent concentration value and an additional additive concentration value;
• first digital means, responsive to said first flow rate detector means, said second flow rate detector means, said third flow rate detector means, said first speed detector means, said second speed detector means, said liquid gel concentrate concentration value and said buffering agent concentration value, for providing a first signal for controlling said first pump means and a second signal for controlling said second pump means;
• and
• second digital means, responsive to said fourth flow rate detector means, said fifth flow rate detector means, said third speed detector means, and said additional additive concentration value, for providing a third signal for controlling said fourth pump means.

A method for producing a fracturing substance, comprising:

• flowing water through a conduit;
• actuating a first pump to flow a liquid gel concentrate into said conduit;
• actuating a second pump to flow a buffering agent into said conduit;
• detecting the rate said water flows through said conduit;
• detecting the speed at which said first pump is actuated;
• detecting the speed at which said second pump is actuated;
• computing, in response to the detected rate of said water and the detected speeds of said first and second pumps, a total flow of a mixture including said water, liquid gel concentrate, and buffering agent through said conduit;
• entering a first numerical value representing a concentration at which said liquid gel concentrate is to be maintained in said mixture;
• entering a second numerical value representing a concentration at which said buffering agent is to be maintained in said mixture;
• controlling said step of actuating said first pump in response to said total flow, said speed at which said first pump is actuated, and said first numerical value;
• controlling said step of actuating said second pump in response to said total flow, said speed at which said second pump is actuated, and said second numerical value;
• flowing said mixture into a holding tank;
• flowing said mixture from said holding tank and into a blender tub having an outlet line through which said mixture flows;
• actuating a third pump to flow an additional additive into said outlet line of said blender tub;
• detecting the rate said mixture flows from said holding tank into said blender tub;
• detecting the speed at which said third pump is actuated;
• entering a third numerical value representing a concentration at which said additional additive is to be maintained in said fracturing substance including said mixture and said additional additive;
• and
• controlling said step of actuating said third pump in response to said rate at which said mixture flows from said holding tank into said blender tub, said speed at which said third pump is actuated, and said third numerical value.