FR2552773A1 - Sodium hydroxide particles for unblocking pipes - Google Patents

Abstract

Sodium hydroxide particles for unblocking pipes are covered with a metal salt of a fatty acid. The salt may be a water-insoluble salt such as calcium stearate, palmutate or laurate or may be a water-soluble salt formed in situ by impregnation of the particle with a saponifiable fatty material (e.g. vegetable or animal oil) followed by water treatment. Also claimed are processes for unblocking pipes using the particles.

Description

Particles of sodium hydroxide for
unblocking of blocked pipes and method
for unblocking a blocked pipe
The present invention relates to sodium hydroxide particles intended for unblocking clogged pipes.

 A common application of sodium hydroxide particles is the unclogging of blocked pipes, in particular pipes for discharging industrial, household or sanitary waste water, blocked by solid organic matter. In this application, particles of sodium hydroxide in bulk are usually poured into the drain pipe, then water is poured onto the bed of particles thus produced, to form an aqueous solution of sodium hydroxide, aggressive vis -to the plug of obstructing materials.

 The practical implementation of this application is however generally made difficult by the highly hygroscopic nature of the sodium hydroxide particles. Indeed, if we do not take special precautions when pouring water on the bed of particles, they are instantly covered with a layer of sparingly soluble sodium hydroxide hydrate, clogging the pores of the bed and preventing effective dissolution of the bed.

 To overcome this drawback of sodium hydroxide particles, consideration has been given to using particles composed of sodium hydroxide, aluminum and a water-soluble nitrate, so that in the presence of water, l aluminum reacts with sodium hydroxide, releasing heat and causing emission of hydrogen gas (US Pat. No. 3,630,936). These composite particles have the drawback of being difficult and expensive to manufacture.

In addition, their handling risks being dangerous for the user, due to the very exothermic nature of the reaction of aluminum with sodium hydroxide in the presence of moisture.

 The invention overcomes the aforementioned drawbacks by providing particles of sodium hydroxide which provide effective unblocking of obstructed pipes, especially waste water discharge pipes, and whose handling and handling are easy and safe.

 To this end, the invention relates to sodium hydroxide particles for unblocking blocked pipes, the particles comprising, in accordance with the invention, a coating with a metal salt of fatty acid.

 The metal salt of fatty acid of the coating of the particles according to the invention can be a salt of saturated or unsaturated fatty acid, containing from 4 to 22 carbon atoms, such as, for example, butyric, caprylic acids, capric, lauric, myristic, palmitic, stearic, oleic and linoleic. Saturated fatty acids, especially those containing 8 to 18 carbon atoms, are preferred.

 The coating of the particles according to the invention can be a soluble coating or a coating insoluble in water.

 Examples of coating insoluble in batten, which can be used in the context of the invention, are insoluble metallic soaps based on alkaline earth metals such as calcium, magnesium and strontium stearates, palmitates, myristates, and laurates.

Stearate, palmitate and calcium laurate are especially suitable.

 Examples of water-soluble coatings which can be used in the context of the invention are ammonium salts and alkali metals of fatty acids such as ammonium stearates, palmitates, oleates, caprylates, laurates and linoleates, sodium, lithium and potassium.

 As a variant, the coating of the sodium hydroxide particles according to the invention may comprise a mixture of metal salts of insoluble fatty acids (for example a mixture of calcium laurate and magnesium palmitate), a mixture of metal salts soluble fatty acids (for example a mixture of sodium stearate and ammonium caprylate) or a mixture of soluble and insoluble salts (for example a mixture of strontium stearate, calcium oleate and sodium stearate sodium).

 The coating must be thick enough to withstand the abrasion forces to which the sodium hydroxide particles are subjected during handling. However, it is advisable to avoid imparting an excessive thickness to the coating, which would then have the effect of preventing or excessively delaying the dissolution of the underlying sodium hydroxide. Generally speaking, the optimum thickness of the coating depends on various parameters, in particular the dimensions and the shape of the sodium hydroxide particles and the nature of the coating, and it must be determined in each case. particular by routine laboratory work. In practice, it turns out to be desirable to make a coating thickness such that there corresponds a coating weight substantially between 0.05 and 2% of the weight of hydroxide sodium. In the case of sodium hydroxide particles having an average diameter of between 0.5 and 3 mm, good results are obtained with an amount of coating of between 0.08 and 1% of the weight of sodium hydroxide.

 The means used to coat the sodium hydroxide particles is not critical. One suitable means is to mix in bulk particles of sodium hydroxide and the coating material in the finely divided liquid or solid state, for example in a rotating horizontal drum.

 According to a particular embodiment of the inversion, the coating of the sodium hydroxide particles comprises a sodium salt of fatty acid formed in situ on the sodium hydroxide particles by impregnating them with a body. saponifiable fat and subsequent treatment of the particles impregnated with water.

In this embodiment of the invention, the saponifiable fatty substance is preferably selected from the triglycerol esters of fatty acids containing from 8 to 18 carbon atoms, such as caprylate, laurate, myristate, stearate, palmitate, linoleate and triglyceride oleate. Advantageously, an animal oil (for example whale oil or fish oil) or a vegetable oil (for example olive oil, soybean oil, flax, palm oil or rapeseed oil). In this embodiment of the invention, the relative amount of saponifiable fatty substance to be used is determined by the thickness of the coating to be formed on the particles.

 According to a particularly advantageous embodiment of this embodiment of the invention, the treatment with water of sodium hydroxide particles impregnated with the saponifiable fatty substance is carried out at the place of use of the particles, for example in a drain pipe. To this end, the particles impregnated with saponifiable fatty substances are poured as such into the pipe and water is then poured into the pipe.

 The sodium hydroxide particles according to the invention may optionally contain other additives such as, for example, a bactericide or a perfume. It is desirable that they be free from thermogenic additive, in particular aluminum.

 The invention applies to sodium hydroxide particles of any shape or size, compatible with their destination for unblocking blocked pipes.

 The invention also relates to a method for unblocking an obstructed pipe, according to which pn pours sodium hydroxide particles according to the invention into the unblocking pipe to form a bed of particles on the plug of obstructing material. the pipe, then water is poured over the particle bed to dissolve the sodium hydroxide.

 In the process according to the invention, the quantity of sodium hydroxide particles to be used depends on the section of the pipe, as well as on the nature and the volume of the plug obstructing the pipe. In the case of a large volume plug, it is possible to operate in several successive stages, by forming and dissolving several successive beds of sodium hydroxide particles.

 The invention applies to the unblocking of all pipes for industrial, urban or domestic liquids, in particular waste liquids such as waste water; it applies for example to the unblocking of sewers or pipes for the evacuation of waste water from sanitary devices such as kitchen sinks, sinks, latrines, washing machines.

 The interest of the invention will emerge from the description of the following examples.

 In the examples, tests were carried out for dissolution in water, of sodium hydroxide particle beds as such or provided with a coating in accordance with the invention. For this purpose, a vertical tube of approximately 25 mm internal diameter was used, closed at its lower part by a perforated plate with a series of holes approximately 3 mm in diameter. To express the ability of a bed of particles to be dissolved in water, 100 g of loose particles are poured into the tube to form a bed about 15 cm thick on the perforated plate, then 250 g of water at 400 ° C. were poured at once into the bed and the time necessary for the entire bed and the water to leave the tube through the perforated plate was measured.

In all the tests, approximately spherical sodium hydroxide particles were used, having the following particle size distribution diameter greater than 2 mm: 48 g / kg diameter between 0.84 and 2 mm: 897 g / kg diameter less than 0.84 mm: 55 g / kg
First series of tests (in accordance with the invention)
Example 1
The sodium hydroxide particles were mixed with a calcium stearate powder, so as to coat them each with a coating of calcium stearate. The quantity by weight of calcium stearate used was equal to 0.2% of the weight of sodium hydroxide.

 The sodium hydroxide particles coated with calcium stearate were then subjected to the bed dissolution test described above. The bed was completely dissolved after 70 seconds of testing.

Example 2
Particles of sodium hydroxide were mixed with soybean oil so as to impregnate the particles with a film of oil having a weight equal to about 0.3% by weight of sodium hydroxide. The oil-impregnated particles were then subjected to the bed dissolution test described above. In this test in the presence of water, the soybean oil film at least partially reacted with the sodium hydroxide of the particles, forming a coating of the sodium salt of fatty acid on their surface.
The dissolution of the particle bed was complete after 75 seconds of testing.

Example 3
The test of Example 2 was repeated, in which the soybean oil was replaced by linseed oil in an amount equal to 0.5% by weight of sodium hydroxide.

 Complete dissolution of the particle bed was complete after 50 seconds.

Reference test (uncoated particles)
Example 4
Sodium hydroxide particles as such, free from coating, were subjected to the bed dissolution test described above. The complete dissolution of the bed required more than 24 hours.

 A comparison of the results of the tests of Examples 1 to 3 (in accordance with the invention) with the reference test of Example 4 immediately shows the interest of the invention.

Claims (10)

 1 - Particles of sodium hydroxide for unblocking clogged pipes, characterized in that they comprise a coating with a metallic salt of fatty acid.  2 - Particles according to claim 1, characterized in that - the coating comprises a metal salt of fatty acid, insoluble in water.  3 - Particles according to claim 2, characterized in that the metal salt of fatty acid is selected from stearate, palmitate and calcium laurate.  4 - Particles according to any one of claims 1 to 3, characterized in that the coating comprises a metal salt of fatty acid, soluble in batten.  5 - Particles according to claim 4, characterized in that the coating comprises a sodium salt of fatty acid formed in situ on the particles by impregnation thereof with a saponifiable fatty substance and treatment of the impregnated particles, with l 'water.  6 - Particles according to claim 5, characterized in that the saponifiable fatty substance is selected from vegetable oils and animal oils.  7 - Particles according to any one of claims 1 to 6, characterized in that they are free of thermogenic additive.  8 - Particles according to any one of claims 1 to 7, characterized in that they have an average diameter between 0.5 and 3 mm and a coating weight between 0.08 and 1% of the weight of sodium hydroxide.  9 - Method for unblocking an obstructed pipe, according to which sodium hydroxide particles are poured into the pipe and water is then poured into the pipe, onto the particles, characterized in that the work of sodium hydroxide particles according to any one of claims 1 to 8.  10 - Method for unblocking an obstructed pipe, according to which sodium hydroxide particles are poured into the pipe and water is then poured into the pipe, onto the particles, characterized in that the works with sodium hydroxide particles impregnated with a saponifiable fatty substance.