Method of heat-moisture treatment products
(57) Abstract:The invention relates to the construction materials industry and can be used for heat treatment and drying of building materials. Method of heat-moisture treatment products in the slit camera products of combustion of natural gas includes the supply and recirculation of the coolant through the heat generator installed at a distance of 2/3 of the length of the chamber from its inlet with the inlet and the intake duct installed with the formation of conditionally closed loop of fluid flow which lead into the lower zone of the chamber perpendicular to the branch return conditionally closed loop. 3 Il. The invention relates to the construction materials industry and can be used for heat treatment and drying of materials.Known heat source,  for the implementation of the steam curing of concrete products. The disadvantage of this method of treatment is to increase the temperature of the medium, which leads to destructive phenomena and lower quality products.There is also known a method of heat treatment of concrete products products of combustion of natural gas  with the application of the heat treatment with a violation of the heat transfer in the upper zone of the chamber due to overlay contours recycling.The objective of the invention is to reduce gas consumption and increase the quality of treatment by gradually increasing the level of temperature fields and uniformity of heating products.The problem is achieved by setting the heat source at a distance of 2/3 of the length of the chamber from its inlet and coolant in the bottom area of the camera perpendicular to conditionally closed loop recirculation of the coolant with the organization of heat and mass transfer. in the upper part of the chamber from the open surface of products.In Fig. 1 shows the layout of the generators of Fig. 2 - cut a slit camera; Fig. 3 the temperature distribution in the center of the panel depending on the temperature in the upper zone of the chamber.The heat source 1 and the recirculation fan 2 (Fig. 2) installed on the floor of a slit camera 5. In the chamber 5 is equipped with a pallet-trolley 4, which are expanded clay, concrete panel 3.For the study of heat and mass transfer in the working chamber 5 were installed chromel-kopelove thermocouple on the camera height and thickness of the product 3, indicated by numerals 1 to 8 in Fig. 2, which corresponds to temperatures
1 coolant in the upper nonpoverty panel;
6 pallet form;
7 coolant in the lower zone of the chamber;
8 the temperature of the concrete in the center of the control cube.An example of the method. The study was conducted in one of the four slit cameras Poltava house-building plant.In Fig. 1 shows the layout of generators. Chamber length 88 m, width 4 m and height 2 m Distance from the rail head to cover is 1.2 m In the slit camera is 11 pallet trolleys length of 8.8 m Material enclosing structures of heavy concrete. On the floor of each chamber according to the project there are three heater CURRENT 1.One is in the area of heating, two in the area of the isothermal heating products. System piping and fans on each camera form a recirculation system that provides heat exchange of the combustion products of natural gas panels.According to the latest recommendations in the Manual for heat treatment of concrete products products of combustion of natural gas (SNiP 3.09.01-85) one heat source in the area of isothermia has been disabled.Research was initially conducted with two remaining generators - mode 1. The camera has three heat is the Amer at the same time is 35 m3concrete exterior wall panels, the weight of the metal mold and the pallet trolleys is 121 soAfter research work of a slit camera mode 1 were carried out detailed studies of the operation of one boiler, installed in the area of isothermia at a distance of 2/3 of the length from the entrance into the camera.This is particularly important installation location of the heat source along the length of the camera, which is one of the main points of the invention. In this case, investigated three possible modes (first with two generators, the second boosted with a single heat source, the processing time of 14 hours and extended - 22 h mode 3 with one generator).A significant role is played by way of the coolant in the slit camera. It turned out that the process of heat-moisture treatment (TWT) can be carried out using only one heat source. For this heat source should be placed at 2/3 of the length from its inlet (58 m), and the coolant should be submitted under the panel, perpendicular to the movement of the trolleys. As a result of this arrangement of the heat generator and method of supplying fluid obtained optimal recirculation of products of combustion of natural gas in the chamber to ensure that the her and a sharp reduction in natural gas consumption.Found in the studies of optimal dimensions of the cross section of the upper zone, allowed to exclude this partition separating thermal zone of a slit camera. As a result, the rate of recirculation of products of combustion in the upper zone of the chamber increased and accordingly, the resulting intensification of the process of heat exchange between the environment and panels. The dimensions of the cross section of the upper zone of a slit camera above the panels was 4,0x0,2 (h) m (Fig. 2).The proposed scheme of installation of one of the heat generator in accordance with the invention is shown in Fig. 1. As a result of changing temperatures and determination of evaporation (moisture) in cross sections of the camera as the movement of the panels on the pallet trolleys found the most effective mode of heat-moisture treatment within a given performance.In Fig. 3 shows the temperature change in the center of the panel and the environment along the camera for three of the investigated modes.the 1st type of modes. Worked two heater CURRENT 1 (one in the preheating zone, the second zone isothermia) the duration of the heat treatment t 17 h curves of temperature changes in the center of the panel depending on the temperature of the environment showed that when outlinename when forced mode above, than a slender 20 - 25oC and 23 39oC than in mode 1. The heating rate of the concrete in the center of the panel was extended mode 2 4oC per hour, when forced mode 2 and mode 1 4 6oC.Also noted a rapid rise of temperature in the initial stage of heating in modes 1 and 2, which leads to intensive evaporation of the mixing water of concrete at the stage of heating and prevents hydration of the cement, which leads to the dryness of the surface of the external wall panels.the 2nd type of modes. Worked one heater CURRENT 1 in the area of isothermia, duration of heat treatment t 14 h (forced mode).the 3rd type of modes. Worked one heater CURRENT 1 in the area of isothermia, duration of heat treatment t 22 h (extended mode).Thus, the elongated mode 3 is less energy intensive than the "forced" mode and mode 1 with two generators, as at the stage of isothermal heating is additional heating of the concrete by isothermal reactions hardening of the concrete, which does not require increasing the consumption of natural gas for the heat treatment of the wall panels.The operation of the two generators in the area of isothermia and Denmark in the upper zone of the chamber;
b) results in excessive gas 1.6 times;
C) leads to "thermal shock" at the stage of heating the exterior wall panels, which leads to destructive phenomena at the boundary layers of expanded-clay lightweight concrete finishing layer and the destruction of adhesion between them.One heat source (mode 3) allows to reduce the temperature to heat the concrete in the area of isothermia to 74 85oC, preventing its increase up to 120 140oC, as recommended SNiP 3.09.01-85 and does not reduce the daily performance of slit cameras.Research and optimization of thermal regimes will reduce the number of generators and recommend change p. 7.2 "Manual on heat treatment of concrete products products of combustion of natural gas (SNiP 3.09.01-85) in terms of mandatory installation of two generators in the cells of continuous operation of more than 200 m3(in our case the volume of the chamber was 650 m3and optimal thermal regime provided one heat source.Soft mode of heat treatment with a single heat source in the area of isothermia eliminates the destructive effects associated with the evaporation of moisture from the body of concrete, has a positive impact on the quality of the item is and the heat and humidity processing concrete 1.6 times, while also improving the quality of the exterior concrete panels. Soft mode of heat-moisture treatment panels contributes to the quality of products within a given performance.When steam curing due to the intensification of recirculation of products of combustion gas obtained by reducing the cross-sectional space of the upper zone of the camera, intensified heat and mass transfer in the slit camera by increasing the coolant flow rate. Provides reduced output humidity external wall panels (about 8.6%) after heating. (According to GOST 13015.083 handling moisture lightweight concrete external wall panels should not exceed 13% close to the equilibrium (5 6%), which significantly improves thermal characteristics of external wall panels).It is established that the efficiency of slit cameras using the coolant of the combustion products of natural gas at the specified method is 82.5 percent, which far exceeds the efficiency of the pit cameras operate on the same carrier (24%).One boiler will reduce the temperature to heat the concrete in the area of isothermia to 74 85oC, preventing its increase up to 120 - 140oC, which recommended SNiP 3.09.01-85, without reducing the daily performance of slot kamaki products in the slit camera products of combustion of natural gas, including supply and recirculation of the fluid products of combustion through a heat source placed on the roof of the tunnel chamber with inlet and the intake duct installed with the formation of conditionally closed loop of fluid in the chamber, wherein the heat source is installed at a distance of 2/3 of the length of the chamber from its inlet, and the flow of the coolant is carried out in a lower zone of the chamber perpendicular to the branch return conditionally closed loop.
FIELD: building industry branches, namely apparatuses for heat treatment of constructions of reinforced concrete erected in building site with use of automatic control of heat treatment processes.
SUBSTANCE: apparatus includes concrete form having electric heating units mounted in its boards for convection-irradiation heating of concrete mixture and heating members mounted in bottom of concrete form for convection-irradiation heating; temperature pickups having individual control circuits and connected to inlets of heat regulators. Outlets of heat regulators are connected through switching units having magnetic starters with respective electric heating units. Each control circuit includes at least six temperature pickups placed in monolithic construction and pickup for measuring temperature of environmental air. Said pickups are connected with inlets of respective programmed heat regulator for supplying control signals.
EFFECT: enhanced quality of constructions.
3 cl, 4 dwg
FIELD: apparatus or processes for treating or working, namely curing, setting or hardening, the shaped articles.
SUBSTANCE: method for gypsum panel forming involves shaping the panel, hardening and hydrating thereof and drying the panel during panel rotation. Device to realize above method is also disclosed.
EFFECT: increased panel quality, decreased production and maintenance costs and improved operating conditions.
20 cl, 11 dwg
FIELD: building, particularly for concreting cast-in-place and precast reinforced concrete structures along with concrete curing temperature regulation.
SUBSTANCE: method involves laying and compacting concrete mix under continuous concrete mix curing temperature control; heating central concrete layers with heating reinforcement when outer concrete layers are in elasto-plastic state. Heating reinforcement is spaced a distance "a" from surface. The heating is carried out simultaneously with surface heat-shielding. Distance "a" is determined as a=δeq(tav-ts)/(ts-ta), m, where δeq - thickness of conditional equivalent concrete layer corresponding to surface thermal resistance, Rs, m; tav - time-average concrete temperature calculated by estimated time of heating directly in heating area, deg; ts - time-average temperature at concrete surface calculated by estimated heating time, deg; δeq is determined as δeq=Rs·λ·F, m, where Rs is heat resistance of rigging with form Rr including thermal resistance Ra of heat transfer from rigging to ambient air, h·deg/kcal; Rs=Rr+Ra=(δr/( λr·F))+(1/(α·F)), h·deg/kcal, where δr is thickness of rigging, m; λr is rigging heat conductivity factor kcal/(m·h·deg), α is rigging surface heat-transfer coefficient kcal/(m2·h·deg), λ is concrete(reinforced concrete) heat conductivity kcal/(m·h·deg); F=1m2 - rigging surface area for thermal resistance calculation, m2. Amount of heat Q used to heat part of member to be heated having length (height) of 1.0 m and cross-sectional width of 1.0 m is determined from Q=(tav-ts)(m+(τ·λ·F/a), where m is constant equal to 60-180 kcal/deg and τ is calculated heating time, hours. The heating reinforcement is heating wires or pipes adapted for hot water circulation.
EFFECT: reduced temperature stresses and prevention of crack formation during structure concreting, as well as possibility to regulate curing temperature.
4 cl, 1 ex, 4 dwg
FIELD: method and equipment for manufacturing gypsum plates.
SUBSTANCE: method involves the following steps: first step includes molding plate; second step includes hardening by hydration process until hydrated article is produced with hydration extent within the range from 33% to 80%; third step includes continuing hydration process in at least one rotating drum by rotating plate around central axis; fourth step includes drying process. Intermediate cutting process may be provided between second and third steps, said cutting process may be effectuated in accordance with wire principle. Apparatus has linear zone for partial hardening and hydration, and at least one hydration drum comprising central axis around which multiplicity of branches are arranged. Each branch in drum may be divided into multiplicity of levers, with surface of said levers making from about 50% to about 99% the surface of respective branch. Drum may have from 10 to 150 branches, preferably from 40 to 120 branches. Hardening and hydration zone and drum may be arranged in two axes extending in parallel with one another.
EFFECT: improved quality of articles, improved maintenance and operating conditions.
12 cl, 11 dwg
FIELD: building industry; methods of production of the construction products at the building industry works.
SUBSTANCE: the invention is pertaining to the field of building industry, in particular, to the method of production of the construction products at the building industry works and may be used for manufacture of the reinforced concrete, including the spatial structures with the heat-insulating layer. The technical result of the invention is reduction of the power input, improvement of the quality and expansion of list of products. The method of manufacture of double-layer reinforced concrete products includes the consecutive formation of the constructive and the heat-insulating layers of the reinforced concrete and its thermal treatment. The heat-insulating layer with the average density of 450-500 kg/m3 made out of the vermiculite-concrete mixture with flowability of 3-5 cm is molded by the vibrobeam with the simultaneous its reinforcement by the woven net in top level. After the structure achieves the plastic strength of 0.015-0.025 MPa, then begin the molding the constructive layer and conduct the thermal treatment by the method of the contact heating from the side of the heat-insulating layer.
EFFECT: the invention ensures reduction of the power input, improvement of the quality and expansion of list of products.
FIELD: construction, particularly devices for thermal treatment of reinforced structures during in-situ structure erection with the use of automatic temperature condition control means.
SUBSTANCE: device comprises form, heat-sensing means, heaters and computer. Heat-sensing means are placed in form. Heaters are laid on reinforcing cage of monolithic reinforced concrete structure and fixed thereto. Heat-sensing means are linked to automatic digital power regulator including indication and control unit and digital control unit connected with control computer by means of signal converter. To provide visual control automatic power regulator is provided with concrete temperature display panel, which indicates concrete temperature in each measurement point and volumetrically weighed average concrete temperature.
EFFECT: decreased power inputs and possibility to control thermal field transformation after heater switching-on or switching-off in correspondence with thermal limiters of valid regulation documents.
2 cl, 3 dwg