Method and apparatus for mixing dry particulate material with a liquid

• US 4,764,019 A
• Filed: 09/01/1987
• Issued: 08/16/1988
• Est. Priority Date: 09/01/1987
• Status: Expired due to Term

• Current Assignee: BJ Services Company
• Original Assignee: Hughes Tool Company (Baker Hughes Company)
• Inventors: Kaminski, Donald R., Sims, Burnie
• Primary Examiner(s): Jenkins, Robert W.
• Application Number:
  US07/091,797
• Time in Patent Office: 350 Days
• Field of Search: 366/6, 366/8, 366/14, 366/15, 366/16, 366/17, 366/136, 366/137, 366/142, 366/152, 366/159, 366/160, 366/161, 366/162, 366/138, 366/141
• US Class Current: 366/15
• CPC Class Codes: B01F 23/59 Mixing systems, i.e. flow charts or diagrams
• CPC Class Codes: G05D 21/02 characterised by the use of electric means

Abstract

An apparatus and method for mixing dry particulate material and liquid is shown. The dry material is initially mixed in a mixing module. The pre-mixed slurry then passes to a two stage mixing tank system featuring a smaller, primary tank and a larger capacity, secondary tank. The premixed slurry passes into the primary tank for additional mixing, then flows over a weir into the secondary tank. A portion of the slurry in the secondary tank is recirculated to the mixing module while the density of the slurry in the primary is monitored. The overall slurry density is controlled by adjusting the dry material entering the mixing module based upon the density reading taken from the primary tank.

Claims

1. A method for mixing dry particulate material with a liquid, comprising the steps of:

initially mixing the dry particulate material with a stream of liquid in a mixing bowl to form a slurry;

passing the slurry through a conduit to a primary tank for additional mixing;

recirculating a portion of the slurry contained in the primary tank through a recirculating loop to further mix the slurry in the primary tank;

passing a portion of the slurry from the primary tank to a larger capacity, secondary tank;

passing a portion of the slurry contained in the secondary tank out a discharge conduit;

recirculating a portion of the slurry contained in the secondary tank to the mixing bowl where it combines with the stream of liquid and dry particulate material entering the mixing bowl;

measuring the density of the slurry contained in the primary tank; and

attaining the desired density in the slurry passing out the discharge conduit by continuing to recirculate slurry from the secondary tank to the mixing bowl while adjusting the entering flow of dry particulate material and liquid entering the mixing bowl based upon the density measurement taken from the primary tank.

2. A method for mixing dry particulate material with a liquid, comprising the steps of:

introducing the dry particulate material from a hopper into a mixing bowl and introducing a stream of liquid into the bowl to initially mix the particulate material and the liquid and form a slurry;

passing the slurry through a conduit to a primary tank for additional mixing, the primary tank being equipped with a spillway which allows overflow into a larger capacity, secondary tank;

recirculating a portion of the slurry contained in the primary tank through a recirculating loop to further mix the slurry in the primary tank;

passing a portion of the slurry contained in the secondary tank out a discharge conduit;

recirculating a portion of the slurry contained in the secondary tank to the mixing bowl where it combines with the stream of liquid and dry particulate material entering the mixing bowl;

measuring the density of the slurry contained in the primary tank by reading the density of the slurry passing through the recirculating loop; and

attaining the desired density in the slurry passing out the discharge conduit by continuing to recirculate slurry from the secondary tank to the mixing bowl while adjusting the entering flow of dry particulate material and liquid entering the mixing bowl based upon the density measurement taken from the primary tank.

3. The method of claim 2, further comprising the steps of:

agitating the slurry contained in the secondary tank with a vertical auger to reduce air entrainment and further mix the slurry.

4. The method of claim 2 further comprising the steps of:

installing a gate valve between the hopper and mixing bowl and adjusting the density of the slurry passing out the discharge conduit by metering the incoming flow of dry particulate material based upon the density reading in the primary tank while continuing to recirculate slurry from the secondary tank to the mixing bowl, the incoming flow of liquid to the mixing bowl remaining constant.

5. The method of claim 2, wherein the capacity of the secondary tank is at least twice that of the primary tank.

6. The method of claim 5, wherein the capacity of the secondary tank is approximately five times that of the primary tank.

7. A method for mixing dry cement and water to form a well cementing slurry, comprising the steps of:

introducing the cement from a hopper into a mixing bowl while introducing a pressurized stream of water into the bowl to initially mix the cement and water and form a cement slurry;

passing the slurry through a conduit to a primary tank for additional mixing, the primary tank being equipped with a spillway which allows overflow into a larger capacity, secondary tank;

recirculating a portion of the slurry contained in the primary tank through a recirculating loop and pumping the slurry back to the primary tank under pressure to further mix the slurry in the primary tank;

passing a portion of the slurry contained in the secondary tank out a discharge conduit to a high pressure pump and from the high pressure pump to the well bore;

agitating the slurry contained in the secondary tank with a vertical auger to reduce air entrainment and further mix the slurry;

recirculating a portion of the slurry contained in the secondary tank to the mixing bowl where it combines with the stream of water and cement entering the mixing bowl;

measuring the density of the slurry contained in the primary tank by reading the density of the slurry passing through the recirculating loop; and

attaining the desired density in the slurry passing out the discharge conduit by continuing to recirculate slurry from the secondary tank to the mixing bowl while adjusting the entering flow of dry cement and water entering the mixing bowl based upon the density measurement taken from the primary tank.

8. An apparatus for mixing dry cement and water to form a well cementing slurry, comprising:

a mixing module including a cement hopper, a mixing bowl, and an inlet stream of pressurized water for initially mixing cement discharged from the hopper into the mixing bowl to form a cement slurry;

a primary tank connected to the mixing module by a conduit whereby slurry from the mixing module passes to the primary tank, the primary tank being equipped with a spillway which allows overflow into a larger capacity, secondary tank;

a first recirculating loop connected to the primary tank and including a recirculating pump for recirculating a portion of the slurry contained in the primary tank through the loop and back to the primary tank under pressure to fur her mix the slurry in the primary tank;

a discharge conduit leading from the secondary tank to a high pressure pump and from the high pressure pump to the well bore;

a vertical auger mounted in the secondary tank for agitating the slurry contained in the secondary tank to reduce air entrainment and further mix the slurry;

a second recirculation loop connecting the secondary tank with the mixing module and including a pump for recirculating a portion of the slurry contained in the secondary tank to the mixing module where it combines with the stream of water and cement entering the mixing module; and

a densimeter located in the first recirculating loop for measuring the density of the slurry contained in the primary tank by reading the density of the slurry passing through the first recirculating loop, the desired density being attained in the slurry exiting through the discharge conduit by continuing to recirculate slurry from the secondary tank to the mixing bowl while adjusting the entering flow of dry cement and water entering the mixing bowl based upon the density measurement taken from the primary tank.