RU2778842C1 - Method for reheating large-diameter pressure hoses at subzero temperatures while removing residual water therefrom - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: method for reheating large-diameter pressure hoses at subzero temperatures while removing residual water therefrom, including the mechanical displacement of residual water by applying a plug; wherein a cylindrical plug made with a front end wall shaped as a cone, pyramid, hemisphere, or ellipsoid is used as a means of displacing water while heating the inner space of the hose, with an autonomous heat source placed on the inside in the form of a soft package with a filler emitting heat when a chemical reaction is started by changing the aggregate state of the filler substance or introducing a catalyst, ensuring heat transfer to the outer surface thereof due to the heat conductivity of the materials no lower than 0.3 W/(m·deg).

EFFECT: ensured reheating of large-diameter pressure hoses.

1 cl

Description

The invention relates to the field of operation of pressure hoses (hereinafter referred to as hoses) designed to transport fire extinguishing agents (water and aqueous solutions) to the fire site, as well as to drain water during emergency response associated with hazardous natural or man-made hydrological phenomena.

Fire and rescue units use high-performance pump-hose complexes (hereinafter referred to as NRK), equipped with hoses of large diameters - up to 300 mm and a length of up to 100 meters or more. For example, NRK with the conditional names “Shkval”, “Flow”, “Magistral”, “Aquarius” (Loginov V.I., Navtsenya N.V., Yakovenko K.Yu. and others. “Development of pump-hose complexes of a new generation” // ISSN2411-3778 "Fire Safety" 2019 No. 2 pp. 24-28; Satsuk I.V. "Analysis of the use of pump-hose systems in extinguishing large fires and eliminating emergencies in Russia and abroad" Collection of materials of the X All-Russian scientific and practical conference "Monitoring, modeling and forecasting of natural hazards and emergencies", Zheleznogorsk 2020, pp. 226-232, http://peleng.info/product/nrk170). These fire and rescue vehicles are designed to supply large masses of water or wastewater over long distances. The use of sleeves for these purposes occurs in three stages:

1) deployment of a hose line up to a kilometer long or more;

2) transportation along the hose line of water and aqueous solutions;

3) upon completion of work, folding the hose line into the hose compartment of the NDT using mechanized devices. (Dorotyuk A.A., Martinovich N.V., Malyutin O.S. “Project office. Results of the project competition” // Fire Business, October 2020, No. 10 pp. 36-41).

Difficulties arise when using sleeves in the winter, especially at the third stage.

After use and the cessation of the water supply, the hoses take on a flat shape, but some water remains in them, relatively evenly distributed in the inner space of the hose. For example, for hoses with a diameter of 300 mm and a length of 100 m - 50-70 l. If the water is not removed in a timely manner, then it, freezing, makes it impossible to roll up the hoses, makes it difficult or impossible to transport them to the location of the fire and rescue unit.

There are many ways and technical solutions to prevent freezing of water. For example [Ref. sources. Diss. Aleshkova et al., RU patent for invention No. 2030194 "Device for extinguishing a fire with superheated water" IPC A62C 33/00, publ. 10.03.1995]. In addition, the very movement of water in the sleeve prevents it from freezing.

The use of the above technical devices and methods used for heating hose lines during water transportation, in this case, is laborious and mostly inefficient, since these devices are used for local heating of the hose or connection head and do not provide heating of the entire hose, as well as water removal from it for subsequent cleaning of the hose line by a mechanized method into the hose compartment.

Various methods and technical means are proposed to ensure the operability of hoses at negative temperatures (“Guidelines for the organization of logistics of the Ministry of the Russian Federation for Civil Defense, Emergencies and Disaster Relief”. Appendix No. 43 “Procedure for the operation of fire hoses”, approved by order Ministry of Emergency Situations of Russia dated 01.10.2020 No. 737). The manual prescribes: “After the fire is extinguished, it is necessary to immediately drain the water from the pressure hoses. Pressure hoses frozen in ice should be warmed up with steam, hot air or a compress from a felt mat moistened with hot water should be used. Frozen hoses or sections of hoses can be brought to the exhaust pipe of a fire truck in order to warm up both the hoses and the coupling heads with the exhaust gases. Before storing pressure hoses, the bending points must be thawed. In the case of continuous freezing of the pressure hoses, they must be assembled without bends and fractures, while they must be transported by trucks with trailers or in another way, avoiding mechanical damage, laying the pressure hoses in full length.

When extinguishing fires at low temperatures, it is necessary to use the recommendations of the manufacturers of pressure hoses.

All of the above methods are of a general nature without specifying how and with what technical means or mobile equipment to supply hot steam or air, especially when extinguishing fires in remote areas with poor road conditions. The use of hot steam or air provides for heating the outer surface of the sleeve, but does not ensure the removal of water from it. The use of hot steam leads to the deposition of water droplets on the surface of the hose, which can freeze after the steam supply is stopped. A felt compress provides local warming of the sleeve.

The technical documentation of manufacturers also does not contain any specific recommendations (Tips Forms).

Known "Device for warming frozen joints of fire hoses" (USSR author's certificate No. 895453 A62S 33/00, publ. 01/07/1982). This device is a kind of use of car exhaust gases. It can be used if free passage of gases inside the hoses is possible. A frozen sleeve on the exhaust pipe can cause the engine to stop and fail.

Sometimes, in practice, torches, blowtorches, and other devices are used for local heating of individual sections of the hose line, connecting heads and other hose fittings. This method can lead to thermal damage to the sleeves.

Moreover, all of the above methods are designed for use with hoses with an inner diameter of up to 150 mm and a length of not more than 20 m (GOST R 51049-2008 "Fire fighting equipment. Pressure fire hoses. General technical requirements. Test methods"). It is not advisable to use hoses with an inner diameter of 200 to 300 mm and a length of 20 m, since the number of connecting heads increases many times, which leads to a significant increase in the mass of the hose line and makes it difficult or impossible to mechanized folding and laying the hose line into the hose compartment of the NDT. The mass of one running meter of a hose with an inner diameter of 200 mm is 2.7 kg, with an inner diameter of 300 mm - about 5 kg, which also makes it impossible to use these heating methods, for example, the heating method by bringing it to the exhaust pipe of a car.

For hoses with an inner diameter of up to 150 mm, after they are warmed up, the remaining water is manually drained, which is impossible for hoses with an inner diameter of 200-300 mm due to their large length and weight.

All of these methods, with the exception of heating by using exhaust gases, provide local heating of a hose line or a separate hose.

Known self-regulating electric heating cable (patent for invention No. 2358416, IPC H05V 3/56, publ. 10.06.2009, bull. No. 16).

The series resistive heating cable comprises a heating element extending longitudinally along the cable. The element contains a semiconductor having a positive temperature coefficient. The heating device comprises a heating element extending longitudinally along the cable, the element comprising a semiconductor having a positive temperature coefficient.

A method for manufacturing a series resistive self-regulating heating cable consists in using a heating element extending in the longitudinal direction along the cable. In the method of manufacturing a heating element, a serial resistive self-regulating cable is used.

This method implies the presence of an additional power supply or changes in the design of the NDT electrical circuit. In addition, the introduction of a conductive wire into the design of the sleeve leads to an increase in the cost of the sleeve and does not ensure the removal of residual moisture after its application. In addition, the hydraulic resistance of the sleeve increases. In this regard, there is a practical need to remove residual moisture from sleeves with a diameter of 200 mm to 300 mm after application at negative temperatures with simultaneous heating in order to restore flexibility and elasticity for folding and mechanized cleaning into the sleeve compartment of the NDT.

A known method of removing residual water from industrial hoses for various purposes with an inner diameter of 200 mm to 300 mm, using cylindrical wads (pistons) made of elastic soft materials. A wad of compressed air from a compressor or other injection device is driven throughout the hose, filling the inner section of the hose and displacing liquid from the entire volume of the hose during movement [https://balticflex.ru/vspomogatelnoe-oborudovanie].

A device is known for cleaning the inner surface of pipes or applying a protective coating on it, made of resilient, elastic, airtight or waterproof solid solid or composite solid material, in particular from foamed polyethylene having a cylindrical shape with recesses or grooves on its surface or without them intended for cleaning pipelines (patent EA005729 B1 IPC B08B 9/0553, publ. 2005-06-30).

The disadvantages of the known method and device are that the wad has an ambient temperature and cannot provide warming of the sleeve after its application. In addition, if ice or ice slurry has formed in the sleeve, the soft wad may not break through the obstacle, it will stop and the task will not be completed.

A device for removing liquid from pipelines is known (author's certificate SU 1079216 A1 IPC A01G 25/00, publ. 03/15/1984), taken as a prototype of the proposed method. The device is intended primarily for removing liquid from flat-folding hoses and is a wad made in the form of a stepped cone with successively increasing diameters of the bases, on the larger of which there is a cuff, the diameter of which is equal to the inner diameter of the hose. Such a wad device eliminates damage to the inner surface of flat-fold hoses. The wad is driven through the hose with compressed air. At the end of the hose, a receiving device is installed - a catcher that ensures the safety of the wad when it exits the hose.

The considered device is functionally most suitable for mechanical displacement of residual water from the inner space of the sleeve, which takes a flat shape after the end of water transportation through it, and does not allow heating the sleeve, since the wad has an ambient temperature. Moreover, if the wad is made of soft materials, then it will also not be able to break through the ice or ice sludge formed in the sleeve.

The inventive method of heating pressure hoses of large diameters at negative temperatures with the simultaneous removal of residual water from them eliminates the above disadvantages.

The essence of the proposed technical solution is as follows.

Part of the volume of the entire wad must be filled with an autonomous heat source in the form of a "chemical heating pad". The operation of such heaters is based on the use in their design of materials that generate heat when starting a chemical reaction by changing the state of aggregation of the filler substance or by introducing a catalyst. Varieties of heaters are produced for various purposes. To start a chemical exothermic reaction, no special tools and knowledge are required. Chemical heaters are used, for example, for heating by fishermen and climbers.

The length of a cylindrical wad must equal or be at least twice the diameter of the wad to prevent rotation of the wad and maintain its shape while moving. The front end wall of the wad is in the form of a cone, pyramid, hemisphere or ellipsoid. A wad with a “chemical heating pad” placed inside and moving inside the sleeve under air pressure simultaneously performs two functions - displacing residual water and heating from the inside of the sleeve along its entire length. Chemical heating pads placed in a wad can be in soft packs of various sizes and shapes. They are reusable. The heating temperature of the heating pad can reach from 50°C to 90°C and be maintained for quite a long time - from 30 minutes or more. The wad provides heat transfer to the outer surface due to the thermal conductivity of materials of at least 0.3 W/(m⋅deg). If necessary, by releasing the pressure created by the compressor, or by adjusting the pressure, it is possible to slow down the movement or stop the wad, additionally heating the sections of the sleeve locally.

Claims (1)

A method for heating pressure hoses of large diameters at negative temperatures with simultaneous removal of residual water from them, including mechanical displacement of residual water by using a wad, characterized in that an elastic soft wad of a cylindrical shape is used as a means of displacing water and simultaneously heating the internal space of the hose. less than two of its diameters, made with a front end wall in the form of a cone, pyramid, hemisphere or ellipsoid with an autonomous heat source placed inside in the form of a soft package with a filler that releases heat when starting a chemical reaction by changing the state of aggregation of the filler substance or introducing a catalyst, providing transmission heat to its outer surface due to the thermal conductivity of materials is not less than 0.3 W/(m⋅deg).