Pressure Hose Research Articles

Technology and technical means for the implementation of reproduction methods for soil fertility

Soil fertility is determined by the presence of humus as the main part of organic matter. The extended reproduction of soil fertility is ensured by the introduction of organic and mineral fertilizers, the cultivation of sidereal crops and the decomposition of plant residues. (Research purpose) The research purpose is developing the technologies and means of mechanization for extended reproduction of fertility. (Materials and methods) For the joint application of liquid organic fertilizers and the cultivation of siderates, a unit has been developed that implements a hose technology for transporting liquid organic fertilizers. Fertilizers are fed through pressure hose lines to the working parts deep into the soil layer. The combined unit consists of a tractor K-744 Kirovets and an adapter for deep tillage with liquid fertilizers, as well as a seeder for small-seeded crops. To level the surface of the field after the passage of the unit and the sealing of the sown seeds of the sideral culture, the unit is equipped with a tooth roller. (Results and discussion) Formulas for determining the critical processing depth are given, the power calculation of the unit is performed. The design of the tillage tool allows to install flat-cutting working parts with a grip of 0.80 meters and slits with a grip of 0.45 meters. Tests of the combined unit were carried out. The depth of tillage was 36±1 centimeters, the seeding rate of the sideral crop (oilseed radish) was 25 kilograms per hectare, the operating speed range of the unit was from 0.4 to 0.8 meters per second. (Conclusions) The uniformity of the subsurface distribution of organic fertilizers was 90-95 percent. The specific energy intensity of the technological process of the combined unit based on the K-744 tractor for intra-soil fertilization is 40-65 kilowatt hours per hectare (excluding the capacity for pumping fertilizers). Energy consumption depends on the depth of cultivation and resistivity of the soil. The proposed method allows preventing water and wind erosion of the soil, improving its agronomically valuable properties. Reducing the pesticide load on the soil and its microflora contributes to the transition to a model of sustainable agroecosystems, improving and improving crop quality. The proposed technology provides extended reproduction of soil fertility.

МОДЕРНИЗАЦИЯ СТРОИТЕЛЬНО-МОНТАЖНОГО ПИСТОЛЕТА ДЛЯ ДОБЫЧИ ПРИРОДНОГО КАМНЯ

The possibility of mechanizing the operation of wedging for the extraction of natural stone was reviewed. The goal is to reduce the weight of the wedges to several kg and reduce the diameter of the holes in the stone where the wedges are installed. The weight of one hydraulic wedge used is 26 kg, not counting the weight of the hydraulic pump with pressure hoses. Among the options for mechanizing stone mining with wedges, the following approaches are considered – the use of the electro-hydraulic effect; application of liquid nitrogen evaporation in a closed volume; use of electromechanical wedge drive. The fourth option was chosen – modernization of the powder actuated fastening tool for the new task. A calculation has been made for a modernized fastening tool. Several fastening tools chambered for a 7,62 × 54,00 mm rifle cartridge with a charge of moderated propagation gunpowder can split a large stone block. Shallow holes are drilled into the stone block into which wedges are inserted. Measures have been taken to compensate for the recoil of a shot. A shot is fired and the wedges, much larger than a concrete anchor, split the stone. The wedges are reusable. The synchronized operation of several tools is ensured by electric firing from one circuit. A modernized tool with an electric triggering for stone mining can weigh below 3,5 kg. The technical details of the proposal are discussed.

Организация подачи (транспортировки) огнетушащих веществ на тушение пожаров способом перекачки

Purpose. For the first time ever the article comprehensively considers issues related to water supply (transportation) to the seat of extinguishing large scale fires over long distances. The authors pay special attention to the conditions determining the choice of pumping as a way of supplying water over long distances. Recommendations are given on the choice of water pumping method and its practical implementation at the fire scene. The calculation method of pump and hose systems implemented during pumping and the express method for determining pumping parameters for practical workers are presented. Methods. Based on extinguishing large scale fires data analysis, topical issues on extinguishing agents supply (transportation) by pumping method were identified, analytical calculations of pump-hose systems parameters implemented when pumping water to the seat of extinguishing large scale fires were made, taking into account tactical and technical characteristics of modern fire trucks. Findings. The proposed method (algorithm) allows converting analytical calculations into accurate calculation system (express method) using a spreadsheet or nomograph. For the first time ever the express calculation table shows the dependence of pumping parameters on the distance between the water source and fire source and the water flow rates supplied by fire pressure hoses. This table allows determining the need of water pumping supply to the fire scene and determining the number of pumping stages; number of fire pressure hoses for pumping; pressure on water tenders fire pumps operating in pumping. Express method provides calculation of water pumping parameters from pump to pump via one or two main hose lines. Research application field. Based on this study, the team of authors developed “Recommendations for applying fire departments tactical capabilities at extinguishing fires and conducting emergency rescue operations.” Conclusions. . Knowledge and application of conditions determining the choice of pumping as a method of supplying (transportation) water over long distances, recommendations for choosing a pumping water method, as well as the methodology for calculating hose systems parameters, the number of main fire trucks for supplying fire extinguishing agents to the fire scene by pumping will increase the level of tactical training of the fire chief. The proposed express method for determining the pumping parameters according to the nomograph allows the fire chief and other officials to reduce the time for making managerial decisions and organizing the supply (transportation) of water for fire extinguishment, as well as reduce the area of extinguishing fires and reduce economic and material damage from them.

CFD model of refuelling through the entire equipment of a hydrogen refuelling station

This paper aims at the development and validation of a computational fluid dynamic (CFD) model for simulations of the refuelling process through the entire equipment of the hydrogen refuelling station (HRS). The absence of such models hinders the design of inherently safer refuelling protocols for an arbitrary combination of HRS equipment, hydrogen storage parameters, and environmental conditions. The CFD model is validated against the complete process of refuelling lasting 195s in Test No.1 performed by the National Renewable Energy Laboratory (NREL). The test equipment includes high-pressure tanks of HRS, pressure control valve (PCV), valves, pipes, breakaway, hose, and nozzle all the way up to three onboard tanks. The model accurately reproduced hydrogen temperature and pressure through the entire line of HRS equipment. A standout feature of the CFD model, distinguishing it from simplified models, is the capability to predict temperature non-uniformity in onboard tanks, a crucial factor with significant safety implications.

Development of a Laboratory-Scale Steam Boiler for Polyurethane (Foam) Waste Recycling Machine

In this paper, a laboratory-scale (small) Steam Boiler was designed and developed for a small-scale polyurethane recycling machine. A small-sized polyurethane machine was developed for the recycling of polyurethane foams to reduce wastes in the polyurethane production industries and also to reuse old discarded foams after their useful lives. It has been observed from studies carried out in many foam manufacturing industries that the polyurethane foam wastes generated from various plant operations are enormous. Also, polyurethane (foam) products are everywhere in our homes, industries and automobiles and are always discarded after their useful lives. These wastes need to be recycled always in other for them not to get back into our ecosystems thereby polluting our environment because polyurethane foams are non-biodegradables and can remain in the environment for a very long time. However, only a few companies with strong financial capabilities are able to embark on this venture because of the high costs of machinery and large quantities of chemicals involved. The high costs of machinery and chemicals also deter cottage industries from participating in the recycling of old and discarded polyurethane foams. Therefore, there is a need to develop small-scale polyurethane foam waste recycling machines to reduce the costs of machinery and chemicals involved in the recycling thereby allowing more participation in the recycling process. The boiler is used to generate high-temperature steam for curing and better bonding of the shredded foams. The heating chamber of the machine consists of the steam boiler, and pressure hose to enable passage of steam from the steam boiler into the molding box. The total volume of the boiler is 2.5 Litres. The outlet steam temperature is 135 0C and 25 psi pressure. The heat rate is 1.52 kJ/s. The recycled foams were able to cure and bonded better with the addition of steam compared to without the steam. The percentage difference in I.F.D, Resilience, Tensile Stress and percent elongation are +0.56, -2.00, +85.45, and +68.39 respectively. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Determining the elongation of T-type pressure fire hoses based on full-scale experiments

The phenomenon of changing the geometric parameters of pressure fire hoses is manifested when they transport extinguishing liquids. Although the extension of pressure fire hoses does not have a significant impact on the fire extinguishing process, the energy costs associated with such changes should be taken into account. In fact, part of the power of the fire pump is spent not on transporting liquids and forming extinguishing jets but on the «optional» lengthening of pressure fire hoses. Latex pressure fire hoses with diameters of 51 mm and 77 mm and fire pressure hoses with double-sided polymer coating of 51 mm (all of type T) were randomly selected for the experiments. The temperature was 263 K and 298 K, the fluid flow rate was constant, the pressure values at the inlet of the Protek 366 fire barrel had fixed values. No significant changes in the diameters (expansion or narrowing) of pressure fire hoses were recorded during water transportation. An elongation of 79 cm with a hose length of 1960 cm (73 cm with a hose length of 1790 cm) was recorded when transporting water in the case of using hoses with a diameter of 77 mm, a pressure at their inlet of 0.8 MPa, a temperature of 263 K, and a water flow rate of 0 l/s. The force that provided such a stretch was 2.04 kN. When extinguishing liquid was supplied by pressure fire hoses with a diameter of 77 mm in the temperature range of 263–298 K, the elongation decreased slightly with decreasing temperature. A slight unevenness of stretching of pressure fire hoses along the length was found when stretching increased closer to their middle. The results indicate the dependence of the amount of stretching on the materials from which pressure fire hoses are made, as well as their diameter. The values of dynamic forces that cause stretching of pressure fire hoses established in the study can be used in practice when taking into account the forced energy losses for fluid transportation

Failure Analysis of High Pressure Hose in Hydraulic Loading System

During the low temperature static test of a certain model, the hose of the hydraulic system leaked oil and bulged. In this paper, through the macroscopic observation and analysis, anatomical observation and analysis, scanning electron microscope analysis and infrared spectrum analysis of the failed high-pressure hose, the reason for the failure of the high-pressure hose is obtained: due to the cracking failure of the inner rubber, the high-pressure oil in the pipe leaks outward, and the outer CPE material leaks or bulges locally. The reason for the cracking of the inner rubber is mainly related to two factors: 1) the inner steel wire winding layer of the hose is locally uneven, and there are bridging and overhead phenomena; 2) the inner rubber has low elongation and poor compatibility of deformation.

Research of the strength characteristics of the most loaded parts of a tower dryer using computer simulation

The strength characteristics of frame devices for lifting fire pressure hoses into a tower dryer are studied using computer simulation. Keywords: pressure hose, tower dryer, lifting device, frame, strength. palpuch@mail.ru, vitaliyivanov@yandex.ru

Assessment of the Impact of Extinguishing with a Low-Pressure Fog Lance on a Fire Environment

A main purpose of the study was to assess the impact of extinguishing with a low-pressure fog lance on a fire environment, especially of temperature. A low-pressure fog lance has recently been recommended for fighting fires in either limited spaces or difficult to access places. Four tests were conducted in real internal fire conditions. The following lances were used in sequential tests: fognail attack, MK with attack head, fognail defense and MK with defense head. They were fed from a fire vehicle GBA 2.5/24 equipped with a pump with automatic pressure regulation and hose lines W75 and W52. The temperature was measured with thermocouples at various points of the room, including the ceiling. Photographic documentation of the tests was prepared using thermal and video cameras. The best way of using a fog lance was established from literature sources and the manufacturer’s requirements. Two main factors of effective firefighting were observed during the tests: smoke cooling and isolation of the fire by formed water vapor. The use of a fog lance significantly improves of fire-fighting operations. A proper application of water mist eliminates the risk of fire gases’ ignition. The assumed times of ensuring safe conditions in the room were confirmed.

HAZARD IDENTIFICATION OF WELDING IN CONFINED SPACE OF THE CEMENT PRODUCTION COMPANY

Introduction: Maintenance of a electrostatic precipitator cooler machine involving welding activities in confined spaces, so the company of cement production need to understand the existing hazard by conducting hazard identification. Welding are related with physical, chemical, mechanical, and electrical hazards that can cause accidents and occupational illnesses. When the welding is carried out in confined spaces, it can increasing the hazards include chemical hazards in the air, configuration of the building structure, poor airflow, or any combination of existing hazards. Methods: This research aimed to conduct hazard identification on welding activities in confined spaces. The research design used a descriptive observational with cross sectional approach. The research population was the workers who repair the electrostatic precipitator cooler machines. Sample of this research were selected using the Purposive sampling method, 2 welders in the rapping bar and 1 safetyman. Primary data was collected by conducting observation and interviews using checklist sheet, secondary data was obtained by collecting company profile and daily safety reports. Result: The results of the analysis showed that the identified hazards of welding activities in confined space are 5 of mechanical hazards, 4 of atmospheric hazards, 5 of ergonomics hazards, 5 of falling hazards, 6 of physical hazards, 5 chemical hazards, and 4 electrical hazards. Conclusion: The conclusion of this research was the dominant potential hazard come from physical hazards consisting of inadequate light, welding sparks, optical radiation, noise, high pressure gas and hoses. Some hazards inflict accidents and illness due to work on welding in confined space are welding sparks, fume, oxygen and asitelyn gases, as well as toxic and carcinogenic substance i.e. cement and coal dust. Keywords: confined space, hazard identification, welding

Алгоритм действий пожарной охраны по сращиванию (наращиванию) рукава высокого давления при тушении пожара на железной дороге

Purpose. Rail transport is one of the safest types of transportation, however, train accidents and catastrophes entail loss of life and significant property damage. A topical issue is the uninterrupted fire suppressant supply in case of fires on the railway. The authors present the results of an experiment on the development of a connecting device prototype to extend high-pressure hoses during firefighting. Methods. The authors have applied a comprehensive analysis of situational factors on the basis of practical experience in conducting fire extinction, preliminary planning and descriptions of the operational situation at a fire scene. The simulation of fire unit actions in extinguishing a fire on the route between stations has been carried out. Tests of the developed sample, a connecting device for high-pressure hoses, have been carried out as well. Findings. The authors have determined a significant degree of influence of fire unit actions on the effectiveness of performing the major combat mission, as well as the possibility of using the optimized management task route by the Fire-Ground Commander. The author team has developed a connecting device prototype to extend high-pressure hoses during fire fighting. Research application field. The study results are aimed at rationalizing the fire extinguishing process and organizing management to perform the main combat mission on the infrastructure of rail-type transport. The results can be applied to improve the forces of units involved in performing the main combat mission, increase the training facilities and capacities of Fire Service and introduce fire protection educational institutions into the process of training as well. Conclusions. The results of the experiment on the development of a connecting device prototype to extend high-pressure hoses during fire fighting in hard-to-reach places are presented. An algorithm for using a high-pressure hose in railway transport is proposed. It will allow reducing the consumption of a fire extinguishing agent relative to normal pressure hoses and increasing the distance for its use.

Establishment of the dependence of the strength indicator of the composite material of pressure hoses on the character of single damages

Experimental studies are presented and the dependence of the change in the strength of the material of a pressure head fire hose of type T with an inner diameter of 77 mm in the longitudinal direction is established, taking into account single damages. The work describes the plan of the experiment and carried out a number of field experiments to determine the effect of the length ld and the depth K damage on the strength F of the hose material, that is, obtaining the dependence F=f (ld, K). A mathematical method of experiment planning was used and a plan was drawn up for a complete multivariate experiment of type 2k with an acceptable model accuracy of 5 %. The limits of variation of the factors are set taking into account a priori information, experimental capabilities and on the basis of the results of preliminary search experiments. The dependence in the coded and natural values of the factors is obtained. The reliability of the relationship was checked using the Fisher test, the calculated value of which was 5.98, which confirms the adequacy of the described process with a probability of 95 %. Analyzing experimental studies of the dependence of the change in the strength of the hose material on the length and depth of damage, it can be said that the change in the strength of the hose almost linearly depends on the specified damage parameters. It is found that with increasing damage, the strength of the hose material significantly decreases. When varying the length factor and the greatest depth of damage, K=0.4 mm, the strength of the hose material decreases from 11.67 kN to 8.77 kN, and in percentage terms by 25 %. The results obtained can be used in practical units of emergency rescue teams, when diagnosing hidden damage in pressure head fire hoses in order to prevent their failure in case of fires

CONCERNING THE DEVELOPMENT OF MODERN TEST EQUIPMENT FOR THE EVALUATION OF QUALITY INDICATORS OF FIRE-FIGHTING LAYFLAT DELIVERY HOSES FOR FIRE AND RESCUE VEHICLES

Pressure fire hoses are one of the main types of fire-fighting equipment, on the serviceable condition of which depends the operational activities of fire and rescue units and successful firefighting. At present, Ukraine has entered into force with (01.08.2021) the national standard, which contains modern European requirements for assessing the quality of flat-hose fire hoses for fire and rescue vehicles. This standard was developed by the Institute of Public Administration and Research in Civil Defense in the framework of research work "Fire hoses – test methods" and adopted by order of SE "UkrNDNC" from 23.03.2021 № 107. In order to assist in solving this problem, the Institute of Public Administration and Research in Civil Defense put into operation, tested and verified the installation for testing fire pressure hoses, which will check the quality of pressure flat hose for fire and rescue vehicles in accordance with modern European requirements. The installation is intended for tests of pressure fire hoses carried out on the following quality indicators: working, test and burst pressure; abrasion resistance; resistance to hot objects; resistance to open flame. The unit is operated at air temperature from 10 ° С to 25 ° С and relative humidity from 15% to 90%. The installation is a metal table, which consists of two levels (upper and lower). The main part of the tests is to be performed at the upper level with the help of three removable modules. The lower level provides one stationary module on which tests for working, test and burst pressure are carried out. The upper level of the installation is designed to test pressure fire hoses for the following quality indicators: resistance to surface abrasion, resistance to point abrasion, resistance to hot objects and resistance to open flames. For versatility and convenience of work on installation on the top level of a table the possibility of change of modules depending on their need is provided. The lower level of the installation is intended for carrying out tests of pressure fire hoses on quality indicators – working and test pressure, bursting pressure. At the lower level of the metal table is a rectangular metal box, which has a closing lid. During the tests, the sample of the test sleeve is automatically filled with water, which drains after the test. To fix the samples of fire hoses of different diameters (25, 32, 38, 51, 66, 77, 100, 125 and 150) mm, the installation includes special cones and plates.

Расчетное обоснование применения рукавов больших диаметров в насосно-рукавных комплексах при ликвидации чрезвычайных ситуаций

Pumping and hose complexes are one of the most efficient technical means used for supplying large volumes of water (up to 200 l/s or more) or drainage over significant (hundreds of meters) distances. Transportation of water and other technical fluids is carried out by hoses of large (over 150 mm) diameters. Operational experience showed that the use of hoses with a diameter of over 250 mm causes small losses of water pressure during transportation along the hoses, but negatively affects the operational and tactical capabilities of the complexes. Due to the large mass of the transported hoses and the significant load on the chassis, the off-road passability of the complexes is reduced; deploying a hose line in a complex natural and urban landscape and cleaning it after an emergency is time-consuming with the involvement of the great number of the uniformed force. The problem of creating new generation pumping and hose complexes required optimization of the diameter of the pressure hoses for ensuring transportation of the maximum possible amount of water over the required distances without critical pressure losses. The performed calculations show that the optimal pressure hose diameter is 225 mm considering technical characteristics of the applied pumping units. Using them it is possible to deploy the hose line at distances from 450 to 1000 m and more depending on the amount of the transported fluid and its pressure at the end of the hose line. Due to the lower mass of the linear meter of the hose and connecting heads, the load on the chassis and on the device for mechanical unfolding and cleaning of the hoses is reduced by more than 29 %, the reliability of chassis units and assemblies and the superstructure of the pumping and hose complexes increases. Correctness of the performed calculations is confirmed by their practical application at the development of the work execution plan on pumping a water-diesel mixture from the emergency zone in the Norilsk region.

Use of modern research methods in the development of new clamp designs for restoring the operability of pressure fire hoses and assessment of their technical condition based on computer modeling

This article is devoted to the issues of restoring the performance of fi re pressure hoses in a fi re when punctures, cuts and fi stulas occur. Failure of fi re pressure hoses in a fi re occurs due to mechanical damage during the laying of main and working lines. In this case, an increase in the working pressure in the bag system leads to the loss of extinguishing agents and the appearance of fi stulas, longitudinal and transverse breaks. This article offers a technical solution aimed at developing a new clamp design to restore the performance of a fi re pressure hose with a diameter of 55 mm when it is damaged: a puncture or cut. For this purpose, a three-dimensional model of the clamp was developed and its strength analysis was performed using the Autodesk Inventor computer-aided design system. This device will allow you to restore the supply of fi re extinguishing agents in the shortest possible time if the pressure hoses are damaged in a fi re.

ПРО МОЖЛИВІСТЬ ПРОГНОЗУВАННЯ МЕХАНІЧНИХ ВЛАСТИВОСТЕЙ ХОЛОДНОДЕФОРМОВАНИХ МЕТАЛОВИРОБІВ ЗІ СТАЛЕЙ ПЕРЛІТНОГО КЛАСУ

In accordance with the latest global trends and modern needs of hardware factories, the demand for wire rod made of pearlitic steels has significantly increased, which can undergo cold plastic deformation with large degrees of reduction and is intended for the manufacture of various commercial products (cold-worked reinforcement, reinforcing ropes, spring wire, steel cord, wire for high pressure hoses, construction fiber, etc.). The most promising direction for increasing the strength class of hot-rolled steels is strain hardening during cold plastic deformation. The structure of cold-worked steels has a more uniform distribution over the cross-section, in contrast to thermally hardened ones, which in the latter case are characterized by annular structural zones formed due to different mechanisms of austenite decomposition. In a number of cases, structural heterogeneity causes instability of the mechanical properties of rolled steel, therefore, there is currently no alternative way to strain hardening. The manufacture of high-strength cold-worked metal products is a complex process and depends on the quality of the wire rod. If the cold-worked hardware does not meet the requirements of the normative documentation for the strength class, then it is no longer possible to ensure the correction of this defect using heat treatment. In this regard, scientific and practical interest has arisen to determine the possibility of creating a method for predictive determination of the mechanical properties of cold-deformed metal products made of pearlitic steels. The features of the influence of cold plastic deformation by on the formation of the strength class of pearlite grade steels with a carbon content of 0.7…0.9 % are considered It is established that the temporary resistance to fracture, at the known parameters of structure and carbon content, lends itself well to mathematical calculations and allows to create predictive models. According to the results of the research, a computer program was created that allows to automatically calculate the energy parameters of drawing and determine the tensile strength of the wire after depending on the total relative compression, parameters of the structure of wire rod and the carbon content in the steel.

USE OF THREADS FROM ULTRA-HIGH-MOLECULAR WEIGHT POLYETHYLENE FOR THE PRODUCTION OF REINFORCING FRAMES FOR FIRE PRESSURE HOSES AS ONE OF THE DIRECTIONS FOR IMPROVING THEIR OPERATING CHARACTERISTICS

The problem of choosing the material of synthetic threads for the production of reinforcing cages of fire pressure hoses with improved performance is considered. A promising direction for the production of new durable and high-tech fire pressure hose is proposed. Using along with traditional polyester yarns based on polyethylene terephthalate (PET), ultra-high molecular weight polyethylene (UHMWPE-threads) which, along with carbon and aramid threads belong to the three “superthreads” and differ from traditional threads, it will increase the strength and resistance to abrasion. Such a fire pressure hose will have significantly higher operational characteristics compared to traditional sleeves based on only polyester threads. The resistance of fire pressure hose to abrasion wear will increase several times (due to the use of UHMWPE threads) under the same operating conditions in intensity, the reliability and durability of the fire pressure hose will increase several times, the strength of the fire pressure hose will increase by at least two, and it will meet the requirements of GOST not only on working pressure 1.6 MPa but also 3.0 MPa (at least for sleeves with a diameter of 38 mm, 51 mm, 66 mm, 79 mm) which makes it universal. The use of a complex synthetic threads consisting of a polyester threads and an equally strong UHMWPE threads in the fire pressure hose reinforcing cage will provide significantly higher performance characteristics of the fire pressure hose compared to traditional sleeves based on polyester threads. Despite the rise in price of the fire pressure hose, due to the use of UHMWPE threads, the strength, wear resistance, reliability and durability of the fire pressure hose increase in several times. A patent has been obtained for use in fire pressure hose of weft complex synthetic threads consisting of traditional polyester threads and UHMWPE threads.

Hydraulic shock suppression mechanism of the hydraulic drive

Researches show that hydraulic shock provokes premature destruction of hydraulic drive high-pressure hoses and unauthorized emission of working fluid into the atmosphere, resulting in environmental pollution. There are ways to protect the machines hydraulic transmission based on the principle of automatic disconnection from the working fluid supply at the hoses damage. However, well known protecting methods do not solve the mentioned problem completely as the hydrodynamic alternating loads caused by hydraulic impact at operation activating when the closing device of the hydraulic drive protecting system do not only destroy the hoses, but also lead to oscillatory process of the locking device shutter, decrease in speed of locking device operation, increase in closing time of the damaged hydraulic line and consequentially increase in a working liquid losses at a high pressure hoses destruction. To eliminate the above-mentioned deficiencies, theoretical and experimental research of the devices parametric characteristics was carried out and a new technical solution was developed which provides increase of closing device functional use while the cotemporaneous design simplifying.

ANALYSIS OF THE BASIC DIRECTIONS OF FIRE HOSES RUPTURE PRESSURES INCREASING

The analysis of the main ways to increase the rupture pressure of these technical products was made based on the rupture pressures dependence in fire pressure hoses from the parameters of their woven reinforcing frame previously obtained by the authors. From a scientific and practical point of view, the main directions for increasing the bursting internal pressures in the FPH (Fire pressure hoses) are identified and analyzed. The developed methodology for calculating and designing of FPH is based on a relationship connecting internal hydraulic pressure p-burst with a breaking load N-burst in the weft thread and a number of other parameters. To assess the influence of the parameters of the FPH woven reinforcing framework on the value of the internal bursting pressure, the latex FPH with a diameter of 77 mm manufactured by BEREG (Russia) made of polyester yarns and designed for a working pressure of 1.6 MPa, was chosen as the object of study. The dependences of the bursting pressures values on the bursting strength of weft threads of FPH woven reinforcing frameworks, designed for a working pressure of 1.6 MPa, for various diameters of the arms cross sections are obtained. The influence of geometric densities on the basis and weft of the woven reinforcing frame on the value of internal burst pressure in the FPH is investigated. When calculating the FPH strength under the action of internal hydraulic pressure, the effect on the value of the burst pressure in latex FPH manufactured by BEREG (Russia), designed for a working pressure of 1.6 MPa, such parameters as sleeve radius, geometric densities of base and weft was studied. When designing and creating new types of FPH, it is necessary to take into account the influence of these parameters on the burst pressure value.

ABOUT IMPROVEMENT OF THE REGULATORY BASE FOR TECHNICAL REQUIREMENTS AND TEST METHODS FOR DELIVERY FIRE HOSES

The urgency of the development of the corresponding national standard, which regulates the technical requirements and test methods for the layflat delivery fire hoses for fire vehicle. Currently, the Operative Rescue Service mainly uses pressure hoses of the “T” type (for fire vehicle ) with a diameter of 51 mm and 77 mm, the technical condition of which often does not meet the requirements, which may not withstand the pressure that pumps of even traditionally used fire vehicle develop when extinguishing fires. The use of such hoses in extinguishing real fires can limit the ability, reduce the effectiveness of operational and tactical operations of operational and rescue units, as well as put personnel at risk. Today, there are a number of complaints from Civil Protection Operations and Rescue units regarding substandard fire hoses being purchased and operated. Basically, the complaints concern the non-conformity of these products with respect to the pressure requirements and the wear resistance of the surface of the material from which it is made. Over the past three years, the State Emergency Service has purchased about 120 fire vehicle each year, which are completed with fire delivery hoses with diameters of 51 and 77 mm. The requirements of the current national standard DSTU 3810-98 in Ukraine are outdated and do not meet the practical needs of today. Taking into account that new types of fire hoses and technologies of their creation have appeared in the leading countries of the world, and considering that the standard in Ukraine DSTU EN 15889: 2017 does not apply to layflat delivery fire hoses for fire vehicles, the issue of developing a national standard for this type of fire hose is urgent. In addition, European regulatory document CEN / TR 16099 states that the EU does not have a single standard that sets the technical requirements for "flat-fire attack hoses", ie those used with fire-fighting pumps. In EU countries, this issue is likely to be governed by the individual national standards of the Member States. This is confirmed by the German national standard DIN 14811-2008 / A1-2012, A2-2014. The technical characteristics and test methods of fire hoses in accordance with current DSTU 3810-98 and German standard DIN 14811-2008 are given. On the basis of analytical research the methods of testing layflat delivery fire hoses are specified, which will be given in the draft national standard. Keywords: layflat delivery fire hoses, rescue vehicles, specifications, test methods.