Cleaning and separation in conduits
A coherent body (B) of wet crushed ice is pumped along a pipe ( 5 ). The crushed ice body can be used as a means of cleaning the pipe wall, as a means of driving a product liquid out of the pipe for recovery, or as a barrier for preventing mixing of two different bodies of liquid ( 1,2 ) in the pipe to either side of it. Being coherent but flowable and non-tensile, the mass of crushed ice can negotiate internal constrictions, obstructions and junctions of the pipe readily, unlike conventional solid or gelled pigs.
1. A method of clearing, cleaning or providing a movable plug in a fluid flow conduit, comprising the steps of: providing a mass of frozen solid particles made by freezing an aqueous or organic liquid; introducing the mass of frozen solid particles into the fluid flow conduit to constitute a body therein, the body comprising a flowable agglomerate mass of the frozen solid particles and of a wetting liquid which comprises the aqueous or organic liquid and a freezing point depressant, the solid particles cohering with one another by means of the wetting liquid; and causing the body to pass along an interior surface of the conduit resulting in contacting of the interior surface of the conduit with the mass of said frozen solid particles.
2. A method according to claim 1 , wherein the wetting liquid consists essentially of said aqueous or organic liquid and of said freezing point depressant.
3. A method according to claim 1 wherein the particles are made by freezing the aqueous liquid and the wetting liquid comprises said aqueous liquid.
4. A method according to claim 1 in which the particles are a frozen liquid food or drink, or frozen liquid ingredient of a food or drink.
5. A method according to claim 2 in which the particle are ice particles.
6. A method according to claim 3 in which the freezing point depressant is one of sugar and salt.
7. A method of clearing, cleaning or providing a movable plug in a fluid flow conduit, comprising the steps of: providing a mass of frozen solid particles made by freezing an aqueous or organic liquid; introducing the mass of frozen solid particles into the fluid flow conduit to constitute a body therein, the body comprising a fluidly flowable and dividable agglomerate mass of the frozen solid particles and a wetting liquid which comprises said aqueous or organic liquid and a freezing point depressant, the frozen solid particles cohering with one another by the wetting liquid; and causing the body to pass along the conduit resulting in plugging of the conduit, and in which the fluid flow conduit has any one or more of the following features:
greater than a 20% change in lateral cross-sectional area of the conduit;
internal local obstructions projecting into the conduit;
branching of the conduit, such that the flowable agglomerate mass divides at the branching of the conduit.
8. A method according to claim 7 , wherein the freezing point depressant is either one of sugar or salt.
9. A method according to claim 7 , wherein the solid particles are ice particles having a particle size of up to 5 mm.
10. A method according to claim 7 in which the solid particles are ice particles and the wetting liquid is water.
11. A method according to claim 10 in which the water contains one of the sugar and salt as a freezing point depressant.