Apparatus for spraying plastic foam

• US 4,107,075 A
• Filed: 12/09/1974
• Issued: 08/15/1978
• Est. Priority Date: 12/09/1974
• Status: Expired due to Term

• Current Assignee: Cover Foam Services, Inc.
• Original Assignee: Fritz Kramer
• Inventors: Kramer, Fritz
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Marcus, Michael S.
• Application Number:
  US05/530,982
• Time in Patent Office: 1,345 Days
• Field of Search: 252/359 E, 261/DIG. 26, 159/DIG. 4, 239/343, 222/190, 260/25 BC
• US Class Current: 422/133
• CPC Class Codes: B29B 7/7409 with supply of gas
• CPC Class Codes: Y10S 261/26 Foam

Abstract

An apparatus for spraying plastic foam includes two containers respectively adapted to hold a solution of a urea-formaldehyde precondensate in a first aqueous medium and a second aqueous medium including a catalyst which causes rapid hardening of the precondensate when the two aqueous media are mixed. A foaming chamber communicates with a source of compressed air and with one of the containers for dispersing the gas in the corresponding medium and for thereby forming a foam. A first conduit connects the foaming chamber to a mixing chamber, and a second conduit connects the other container to the mixing chamber. A third conduit leads outward of the mixing chamber and terminates in a nozzle orifice normally open to the atmosphere. The compressed air is used for conveying the foam and the medium in the other container to the mixing chamber for continuously mixing the contents of the mixing chamber and for conveying the resulting mixture outward through the nozzle orifice when the latter is open. When the orifice is blocked, a check valve in the first conduit prevents flow of the catalyzed mixture into the foaming chamber.

Claims

1. A plastic foam spraying apparatus comprising:

(a) a first container adapted to hold a solution of a urea-formaldehyde precondensate in a first aqueous medium free from catalyst;

(b) a second container adapted to hold a second aqueous medium including a catalyst capable of causing rapid hardening of said precondensate when said first medium is mixed with said second medium;

(c) supply means for supplying a gas under a pressure higher than atmospheric pressure;

(d) conduit means connecting said supply means to said first and second containers;

(e) foaming means including a foaming chamber communicating with said supply means and with said first container for dispersing said gas in said first medium and for thereby forming a foam in said foaming chamber;

(f) a mixing chamber;

(g) a first conduit connecting said foaming chamber to said mixing chamber;

(h) a second conduit connecting said second container to said mixing chamber;

(i) a third conduit leading outward of said mixing chamber and terminating in an orifice normally open to the atmosphere, whereby said gas under pressure

(1) conveys said foam from said foaming chamber to said mixing chamber through said first conduit,

(2) conveys said second medium from said second container to said mixing chamber through said second conduit,

(3) mixes the conveyed foam and the conveyed second medium in said mixing chamber, and

(4) conveys the mixture so produced outward of said mixing chamber through said third conduit when said orifice is open to the atmosphere; and

(j) check valve means in said first conduit for preventing flow of said mixture toward said foaming chamber when said orifice is blocked.