Apparatus and method to produce foam, and foamed concrete

• US 4,872,913 A
• Filed: 06/20/1988
• Issued: 10/10/1989
• Est. Priority Date: 01/12/1987
• Status: Expired due to Fees

• Current Assignee: Standard Concrete Products, Inc.
• Original Assignee: Standard Concrete Products, Inc.
• Inventors: Dunton, Harvey R., Rez, Donald H.
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): Brunsman, David M.
• Application Number:
  US07/208,579
• Time in Patent Office: 477 Days
• Field of Search: 106/86, 106/88, 106/90, 106/97, 106/91, 106/93
• US Class Current: 521/55
• CPC Class Codes: B01F 23/291 for obtaining foams or aerosols
• CPC Class Codes: B28C 5/386 Plants; Systems; Methods

Abstract

A method for forming foam, useful in mixing with concrete at a batching plant, includes the steps:

a) supplying a synthetic resinous foaming agent, in liquid form,

b) combining the foaming agent with water, to form a liquid mix, and pressurizing the mix,

c) adding pressurized air to the mix,

d) sub-dividing the mix into droplets, in a confined flowing stream,

e) reducing the stream confinement,

f) whereby the droplets expand as a foam.

Claims

1. The method of producing an improved concrete that includes:

(a) providing a synthetic resinous foaming agent, in liquid form, to a reciprocating pump and repeatedly drawing said agent and water into the pump for combining the foaming agent with water in the pump to continuously form a liquid mix, and repeatedly discharging quantities of the liquid mix from the pump,

(b) adding pressurized air to the mix discharged from the pump, sub-dividing the mix into droplets, in a confined flowing stream, and reducing the stress confinement, whereby the droplets expand to form a foam,

(c) forming an aqueous calcareous concrete mix, said concrete mix containing said particles, calcareous cement particles, aggregate pieces and water, adding said foam to the concrete mix, and sizing the foam before adding it to the concrete mix, to pass only bubbles of about 5 to 25 micron sphere size to the concrete mix, and mixing together the concrete mix and added foam bubbles of said micron sphere size,

(d) the ratio by volume of foam added to the concrete mix being between 1/2and 5 cubic feet of foam per cubic yard of concrete mix,

(e) the bubbles passed to the concrete mix having substantially the same sizes as the cement particles,

(f) the mix and foam being added to a rotary drum on a delivery truck, and mixing the concrete mix and foam by rotating said drum as the truck travels to a job site.

2. Lightweight concrete produced by the method of claim 1.

3. The method of claim 1 including pre-mixing the foam and concrete mix in a batching tank, and then passing the foam and concrete mix to said drum as aforesaid.

4. The method of forming a foam and calcareous concrete mix, and employing a rotating concrete mixing drum on a truck, that includes:

(a) metering amounts A of water and B of synthetic resinous foaming agent in liquid form, and sequentially combining amounts A respectively with amounts B, to form a sequence of metered and combined quantities A and B in a flowing stream, adding pressurized air to said metered and combined quantities A and B to pressurize same, in a confined stream,

(b) reducing the stream confinement to allow foam production and adding the unconfined stream to the calcareous concrete mix in the rotary mixing drum,

(c) and rotating the drum to mix the water, concrete mix, agent and foam thereby to enhance foam mix production and mixing as the truck moves to a job site, the foam comprising bubbles of about 5 to 25 micron sphere size only,

(d) said amount of said agent being such as to form between 1/2 and 5 cubic feet of foam per cubic yard of the concrete mix in the rotating drum.

5. The method of claim 4 wherein saisd agent comprises methyl cellulose.

6. The method of claim 4 including providing a screen and passing foam through the screen prior to addition to the drum, to control the bubble size.

7. The method of claim 6 including pressurizing said agent added to said stream of water.

8. The method of claim 4 wherein said reducing of stream confinement is effected through a nozzle acting to subdivide the stream into droplets flowing toward the drum.