BALAKIREV, Mikhail Stepanovich (54 30-letiya Pobedy St.. selo Novopokrovka, Krasnogvardejskii rayonAutonomous Republic, 97026, UA)
TOMASHEVSKYY, Sergei Petrovich (5-B Bulgakova St, apt.172Kiev, 03134, UA)
BALAKIREV, Mikhail Stepanovich (54 30-letiya Pobedy St.. selo Novopokrovka, Krasnogvardejskii rayonAutonomous Republic, 97026, UA)
TOMASHEVSKYY, Sergei Petrovich (5-B Bulgakova St, apt.172Kiev, 03134, UA)
| CLAIMS I A method for thermal-pulse treatment of pieces comprising: (a) placing of at least one piece within a closed heatproof and impact-resistant chamber (1) which is equipped with a movable damped cover (6); (b) supply of a charge of an explosive gaseous mixture into said chamber (1 ), (c) blast initiation of this charge and holding at least one said piece in contact with gaseous explosion products on conditions that their temperature and pressure will decrease immediately within the hollow of said chamber (1) owing to raising of the movable damped cover (6), (d) relief of residual pressure by venting of spent gases into atmosphere, and (e) evacuation of finished pieces from said chamber (1). 2. The method according to the claim 1 , wherein a force necessary for raising of said movable damped cover (6) is specified before blast initiation of the charge of the explosive gaseous mixture. 3. An apparatus for thermal-pulse treatment of pieces comprising: (1) a removable heatproof and impact-resistant chamber (1), which is connected to sources of a combustible gas and a gaseous oxidant by means of adjustable feeders (3, 4) and a mixer (2), and which is equipped with a flame igniter (5) and a movable damped cover (6) that is assembled kinematically with said chamber (1) using suitable damper; (2) a heatproof and impact-resistant base (7) that is rigidly fixed, in operating position, to the said chamber (1) and has a through-hole for discharge of gaseous explosion products and a gas-outlet pipe (8) arranged immediately after said through-hole; (3) an unit for relief of residual pressure, venting of spent gases into atmosphere and removing of solid fine-dispersed by-products, which has: (3.1) a bowl-shaped housing (9) that is rigidly fixed to the said base (7) and has an opened into atmosphere exhaust pipe (10) located at its upper part and a draining fitting (11) located at its near-bottom part, (3.2) an insertion piece (12) that is fixed concentrically within said housing (9) and rigidly fixed also to the said base (7) and has a hollow, which is divided by a ring-shaped partition (13) into an upper part and a lower part; at that said upper part loosely embraces said gas-outlet pipe (8), is connected to a source of a liquid and serves as a hydraulic damper and a trap of fine-dispersed by-products of the thermal-pulse treatment; and said lower part is connected to the hollow of said bowl-shaped housing (9) by means of at least one drain port (15) that is located under the inlet of said draining fitting (11), (3.3) a spool-type valve which is located in the lower part of said insertion piece's (12) hollow and has: a saddle (16) located in the lower part of said ring-shaped partition (13) at the extension of said gas-outlet pipe's (8) geometrical axis, a movable sliding piston (17) that has such upper end surface, which is compatible with surface of said saddle (16), and a retractable rod (18) equipped with such centring piece (19), which is inserted initially into said gas-outlet pipe (8), and a suitable means for reset of the sliding piston (17) to upper position after each operating cycle. 4. The apparatus according to the claim 3, wherein: said movable damped cover (6) is stepped along its height and has a relatively small in breadth lower part, which contacts with the inside surface of the heatproof and impact- resistant chamber (1), and a relatively broad upper part, and said damper is made as a pneumocylinder, wherein the casing (21) embraces hermetically said heatproof and impact-resistant chamber (1) from above, the piston is made as the upper part of said movable damped cover (6), and the piston rod (22) is rigidly connected by its lower end to the said upper part of said movable damped cover (6) and by its upper end to a regulator (23) of free running. 5. The apparatus according to the claim 3, wherein a gas distributor (24) is mounted at the outlet of the mixer (2) of combustible gas and gaseous oxidant, and this gas distributor (24) has first outlet channel (25) opened into the heatproof and impact-resistant chamber (1) and second outlet channel (26) opened into the airspace of said insertion piece (12) located in said bowl-shaped housing (9). |
Field of the Invention The invention relates - to a method for thermal-pulse treatment of various pieces, which are made from metal or polymeric materials by cutting, forging, punching, or casting (including die casting), for the purpose of deburring and/or waste removal from theirs, for the case-hardening, and for preferably accompanying smoothing and/or mechanical hardening of the surfaces of the pieces, and to a structure of apparatuses for carrying out of the above-mentioned method.
Background Art
Thermal-pulse treatment of various pieces using high-temperature gaseous medium within a closed chamber is known for a long time. In fact, US 3,475,229 (1969) discloses a method for deburring of metal pieces. This method includes: placing of as-formed pieces within a closed (and, usually, heat-insulated) heatproof and impact-resistant chamber; thermal pulse generation in gaseous medium within said closed chamber and thermal pulse treatment of said pieces during time that is sufficient for their deburring; relief of overpressure and discharge of the spent gases into atmosphere; evacuation of finished pieces from said chamber; and repeating of the above-described production cycle.
This patent discloses also multiple apparatuses based on different principles of thermal pulse generation for carrying out of said method. One of a number of these apparatuses provides said generation by explosion of a charge of a mixture of a combustible gas and a gaseous oxidant within said chamber.
Variation of chemical composition and mass of each separate charge of mentioned explosive mixture allows effective regulation of enthalpy, kinetic energy and chemical composition of high-temperature gaseous explosion products depending on materials and dimension-types of as-formed pieces. In fact, if explosive mixture contains an oxidant in excess, it provides for "burning-out" of rough edges and burrs, if explosive mixture contains a combustible gas and a gaseous oxidant taken in stoichiometric ratio, it provides neutral chemical composition of gaseous explosion products and, respectively, eliminates surface oxidation or reduction of processed pieces, and if explosive mixture contains a combustible gas excess, it provides reduction potential of gaseous explosion products and, respectively, oxide ablation from surface of processed pieces.
It is clear that explosion happens extremely quickly. Therefore, warming-up of as- formed pieces is practically adiabatic process, in which temperature and pressure within said heatproof and impact-resistant chamber increase very rapidly. Thus, prime object of development of the thermal-pulse technology was secure closing of active zone during each explosion. In fact, US 3,666,252 (1972) discloses an apparatus for deburring of pieces having a mobile support. This support is connected to a vertical reciprocal motion drive and may close said chamber safely. However, processed pieces placed in such apparatus contact with high-temperature gaseous explosion products during time which is sum of periods those are necessary for explosion of the explosive gaseous mixture charge, lowering of said support and relief of overpressure. Indeed, the instantaneous venting of the gaseous explosion products, which have temperature substantially more than 1000 0 C and a pressure more than 70 megapascal, is extremely dangerous. Thus, the chamber opening must be only gradual.
In that case reduction of temperature and pressure, which is caused by dilatation of gaseous explosion products, occurs too slowly (as a rule substantially longer than 10 ms). Respectively, it is impossible to prevent overheating of the processed pieces and their contamination by fine solid particles, which are by-products of the thermal-pulse treatment of pieces and/or the wear debris of the camber wall, and oxidation of the processed pieces in case of excess of the oxidant in the explosive mixture.
Naturally, undesirable effects of the overheating and impact action of the detonation wave (such as alterations of composition, structure and physical and mechanical properties of surface layers of the finished pieces) are as more visible as less their weight, thermal conductivity and breaking point (at pressing) of their material and as easy this material falls into thermo-mechanical destruction.
Respectively, a method of regulation of the time, during which the processed pieces contact with high-temperature gaseous medium, was created at the next step of development of the thermal-pulse treatment. So, in SU 1129042 disclosed the method, the subject matter of which is the nearest to the proposed hereinafter method. This known method includes:
(a) placing of at least one as-formed piece, which is meant for thermal-pulse treatment, within a tightly closed heatproof and impact-resistant chamber;
(b) supply of a charge of an explosive gaseous mixture into said chamber,
(c) initiation of an explosion of this mixture and holding the piece (or pieces) in contact with the high-temperature gaseous explosion products under maximal overpressure within the chamber during time in the range from 0.001 s to 0.01 s,
(d) following relief of overpressure by discharge of the spent gases into atmosphere during the time from 0.0001 s to 0.1 s,
(e) evacuation of finished pieces from said chamber. An apparatus for realization of this method is known from SU 1592363. It has:
(1) a bell-shaped removable heatproof and impact-resistant chamber, which is connected to a sources of a combustible gas and a gaseous oxidant and is equipped with a flame igniter;
(2) a heatproof and impact-resistant base which has a central through-hole and a gas- O outlet pipe at the end of said through-hole for venting of gaseous explosion products, and which locks said chamber at the working position;
(3) an unit for relief of overpressure, venting of gaseous explosion products into atmosphere, and removing of fine-dispersed solid by-products; the unit has: (3.1) a bowl-shaped housing that is rigidly fixed to the heatproof and impact-resistant base and is equipped with an open into atmosphere exhaust pipe at its upper part and with a draining pipe at its near-bottom part,
(3.2) a placed within the bowl-shaped housing hydraulic damper, the casing of which is rigidly fastened to the said base, connected to a source of a liquid, embraces said gas-outlet pipe loosely and is equipped at its lower end with a saddle that is coaxial to the said pipe, and
(3.3) a spool-type valve having - a hollow casing fastened to the lower part of said bowl-shaped housing at the extension of a geometrical axis of said gas-outlet pipe and said saddle; this casing also has at least one drain port meant for passing of gases into its near-bottom part, and a sliding piston that is movable within said hollow casing, has mirror-like to the contact area of said saddle upper end surface, is equipped at the bottom with a suitable arrester, and is connected to a suitable drive for its reset to the upper position after each operating cycle.
So far as said hydraulic damper is connected to the hollow of the heatproof and impact- resistant chamber through the narrow channel of said gas-outlet pipe, the processed pieces are being under the initial pressure of high-temperature gaseous explosion products no less than 1 ms, and only then they could cool down owing to strangling of said explosion products. Unfortunately, practical use of the described technology shows that overheating of processed pieces is often too great. Respectively, alterations of chemical composition and physical and mechanical properties of surface layers are occurred even if said pieces were made from steel. Moreover, solid fine-dispersed by-products of thermal-pulse treatment and wear debris of the said chamber and said base walls precipitate onto surface of processed pieces and penetrate into their material. These undesirable effects are especially visible if said pieces were made from light alloys and heatproof polymeric materials.
Summary of the Invention The invention is based on the problem of creation - by regulation of the volume of high- temperature products of explosion of each charge of explosive gaseous mixture - such thermal-pulse treatment technology which could substantially decrease overheating and surface contamination of processed pieces.
First of all, this problem is solved in that a proposed method for thermal-pulse treatment of pieces includes following steps:
(a) placing of at least one piece within a closed heatproof and impact-resistant chamber, which is equipped with a movable damped cover;
(b) supply of a charge of an explosive gaseous mixture into said chamber,
(c) blast initiation of this charge and holding at least one said piece in contact with gaseous explosion products on conditions that their temperature and pressure will decrease immediately within the hollow of said chamber owing to raising of the movable damped cover,
(d) relief of residual pressure by venting of spent gases into atmosphere, and
(e) evacuation of finished pieces from said chamber. In fact, raising of said movable damped cover causes dilatation and respective decreasing of temperature and pressure of the gaseous explosion products within the heatproof and impact-resistant chamber practically at the same time when thermal-pulse treatment starts. This reduces overheating of the finished pieces and contamination of their surface by fine-dispersed solid by-products of the thermal-pulse treatment. The additional feature consists in that a force necessary for raising of said movable damped cover is specified before blast initiation of the charge of the explosive gaseous mixture.
Said problem is solved also in that a proposed apparatus for thermal-pulse treatment of pieces comprises of: (1) a removable heatproof and impact-resistant chamber, which is connected to sources of a combustible gas and a gaseous oxidant by means of adjustable feeders and a mixer, and which is equipped with a flame igniter and a movable damped cover that is assembled kinematically with said chamber using suitable damper;
(2) a heatproof and impact-resistant base that is rigidly fixed, in operating position, to the said chamber and has a through-hole for discharge of gaseous explosion products and a gas-outlet pipe arranged immediately after said through-hole;
(3) an unit for relief of residual pressure, venting of spent gases into atmosphere, and removing of solid fine-dispersed by-products, which has:
(3.1) a bowl-shaped housing that is rigidly fixed to the said base and has an opened into atmosphere exhaust pipe located at its upper part and a draining fitting located at its near-bottom part,
(3.2) an insertion piece that is fixed concentrically within said housing and rigidly fixed also to the said base and has a hollow, which is divided by a ring-shaped partition into an upper part and a lower part; at that said upper part loosely embraces said gas-outlet pipe, is connected to a source of a liquid and serves as a hydraulic damper and a trap of fine- dispersed by-products of the thermal-pulse treatment; and said lower part is connected to the hollow of said bowl-shaped housing by means of at least one drain port that is located under the inlet of said draining fitting,
(3.3) a spool-type valve which is located in the lower part of said insertion piece's hollow and has: a saddle located in the lower part of said ring-shaped partition at the extension of said gas-outlet pipe's geometrical axis, a movable sliding piston that has such upper end surface, which is compatible with surface of said saddle, and a retractable rod equipped with such centring piece, which is inserted initially into said gas-outlet pipe, and a suitable means for reset of the sliding piston to upper position after each operating cycle.
This apparatus allows to realize the proposed method in practice and to obtain aforesaid technical effect.
First additional feature consists in that - said movable damped cover is stepped along its height and has a relatively small in breadth lower part, which contacts with the inside surface of the heatproof and impact- resistant chamber, and a relatively broad upper part, and said damper is made as a pneumocylinder, wherein the casing embraces hermetically said heatproof and impact-resistant chamber from above, the piston is made as the upper part of said movable cover, and the piston rod is rigidly connected by its lower end to the said upper part of said movable damped cover and by its upper end to a regulator of free running. These features allow adjusting the thermal-pulse treatment mode taking into consideration sizes, geometrical shapes and weight of processed pieces and physical and mechanical properties of their materials.
The second additional feature consists in that a gas distributor is mounted at the outlet of the mixer of the combustible gas and the gaseous oxidant, and this gas distributor has first outlet channel opened into the heatproof and impact-resistant chamber and second outlet channel opened into the airspace of said insertion piece located in said bowl-shaped housing. This allows, firstly, to modify procedure of supply of the explosive gaseous mixture for the purpose of adaptable regulation of duration and energy of action of each detonation wave onto pieces processed within the closed heatproof and impact-resistant chamber, and, secondly, to adjust the operating time of the spool-type valve. Brief Description of the Drawings
The subject matter of the invention is further explained by detailed description of proposed apparatus for thermal-pulse treatment of various pieces and proposed method of such treatment with references to the attached drawings, where -
Fig.1 shows an apparatus for thermal-pulse treatment of pieces in initial position before blast initiation of a charge of an explosive gaseous mixture (longitudinal section by vertical symmetry plane with conditionally removed thermo-insulation);
Fig.2 shows the same apparatus after explosion of said charge of said mixture.
The best Embodiments of the Invention
Proposed method for thermal-pulse treatment of pieces is based on use of an apparatus, which has at least following parts (see Fig.1 ): a removable heatproof and impact-resistant chamber 1 , which is connected to (not shown here) sources of a combustible gas and a gaseous oxidant by means of a mixer 2 and adjustable preferably volumetric feeders 3 and 4, and which is equipped with a flame igniter 5
(e.g. in the form of a spark or heater plug) and with a movable damped cover 6 that is assembled kinematically with said chamber 1 using disclosed hereinafter suitable damper; a heatproof and impact-resistant base 7 that is rigidly fixed, in operating position, to the said chamber 1 and has a not designated especially preferably central through-hole for discharge of gaseous explosion products and a gas-outlet pipe 8 arranged immediately after said through-hole; and an unit meant for relief of residual pressure, venting of spent gases into atmosphere, and removing of solid fine-dispersed by-products of thermal-pulse treatment and wear debris of the camber 1 and the base 7 walls.
This unit comprises of: first, a bowl-shaped housing 9 that is rigidly fixed to the heatproof and impact-resistant base 7 and has an opened into atmosphere exhaust pipe 10 located at its upper part and a draining fitting 11 located at its near-bottom part, second, an insertion piece 12 that is fixed concentrically within said housing 9 and rigidly fixed also to the said base 7 and has a hollow, which is divided by a ring-shaped partition 13 into an upper part and a lower part; at that said upper part loosely embraces said gas-outlet pipe 8, connected to a source of a liquid (usually process water ' 1 PW) through a metering valve 14 and serves as a hydraulic damper and a trap of fine-dispersed by-products of the thermal-pulse treatment; and said lower part is connected to the hollow of said bowl- shaped housing 9 by means of at least one drain port 15 that is located under the inlet of said draining fitting 11 , and third, a spool-type valve that is located in the lower part of said hollow of the insertion piece 12.
This spool-type valve comprises of: a saddle 16 located in the lower part of said ring-shaped partition 13 at the extension of said gas-outlet pipe's 8 geometrical axis, a movable sliding piston 17 having such upper end surface, which is compatible with surface of said saddle 16, and a retractable rod 18 equipped with such (e.g. conical or spherical) centring piece 19, which is inserted initially into said gas-outlet pipe 8, and a suitable means for reset of said piston 17 to upper position after each operating cycle (e.g. a pneumocylinder that is conventionally shown on the drawings by an up-directed arrow «P»).
The retractable rod 18 is connected kinematically with a suitable (e.g. screw) regulator 20 that regulates position of said rod 18 within the channel of the gas-outlet pipe 8.
As a rule, the movable damped cover 6 is stepped along its height and has a relatively small in breadth lower part, which can slide relative to the inside surface of the heatproof and impact-resistant chamber 1 , and a relatively broad upper part; and above-mentioned damper of said cover 6 is made as a pneumocylinder. Its casing 21 embraces hermetically said heatproof and impact-resistant chamber 1 from above, a piston of this pneumocylinder is made as the upper part of said movable damped cover 6, and a piston rod 22 is rigidly connected by its lower end to the said upper part of said movable damped cover 6 and by its upper end to a (e.g. screw) regulator 23 of free running.
It is expedient to mount a gas distributor 24 at the outlet of the mixer 2 of the combustible gas and the gaseous oxidant. This gas distributor 24 has first outlet channel 25 opened into the heatproof and impact-resistant chamber 1 and second outlet channel 26 opened into the airspace of said insertion piece 12 located in said bowl-shaped housing 9. It is clear for each person skilled in the art that said gas distributor 24 is equipped with a not shown especially controlled three-way stopcock for supply of the explosive mixture into one of the channels 25 or 26 in full or into both channels 25 and 26 according to the previously defined ratio. Flame igniter 5 can be inserted into the hollow of the heatproof and impact-resistant chamber 1 , but it is preferable if this igniter 5 is built-in into the outlet of the mixer 2, as it is shown on the drawings.
The person skilled in the art must understand that proposed apparatus is equipped by not shown especially an usual automatic control system having available parts such as - setting devices and sensors of temperature and pressure, setting devices, sensors and controllers of consumption of components of an explosive mixture before its preparation and of consumption of the prepared explosive mixture, at least one program control unit based on a suitable microprocessor etc.
Naturally, all such additions are included to the measure of rights limited by the following claims only.
Each operating cycle of the thermal-pulse treatment of pieces includes preparatory, processing and discharging stages which are carried out in the following way.
At the start of the preparatory stage at least one not shown as-formed piece is been placed (immediately or together with an additional suitable support) on the heatproof and impact-resistant base 7. Then the heatproof and impact-resistant chamber 1 must be thoroughly closed by the movable damped cover 6 and both these parts must be hermetically connected to the heatproof and impact-resistant base 7, and allowable value of free running of the piston rod 22 and said cover 6 in the pneumocylinder casing 21 must be set by the regulator 23. In order to prevent overheating of air within the pneumocylinder casing 21 and to regulate a damping force an amount of a refrigerating fluid (preferably process water) can be poured on relatively broad part of the movable damped cover 6 using not shown especially through-hole.
Next the spool-type valve must be adjusted to the necessary operating time. Thereto the retractable rod 18 together with the centring piece 19 must be set by the regulator 20 to the defined (as a rule by previous experiments) distance from the upper end surface of the sliding piston 17. Generally, the desired operating time would be as greater as deeper the centring piece 19 would be inserted into the gas-outlet pipe 8.
Further an amount of the water is being poured by means of the metering valve 14 into the upper part of the insertion piece's 12 hollow. A part of this water overflows through the drain ports 15 into the housing's 9 bottom part when the sliding piston 17 is opened. When said water rises up to the draining fitting's 11 inlet level, the sliding piston 17 is been raised up to contact with the saddle 16 and the drain ports 15 is been closed. Thus, the active zone, which includes all hollow of said camber 1 and the part of the channel of the gas-outlet pipe 8 placed above the centring piece 19, will have been sealed finally.
The preparatory stage has been ended when the charge of the explosive mixture has been prepared and supplied into the active zone of the apparatus for thermal-pulse treatment. Said mixture comprises of a combustible gas selected usually from the group consisting of hydrogen, methane, acetylene and other pure low-molecular hydrocarbons and/or their mixtures, and a gaseous oxidant, which can be atmospheric air or, rarely, pure oxygen.
The selected combustible gas and the selected gaseous oxidant are being supplied respectively through the feeders 3 and 4 into the mixer 2. The prepared charge of the explosive gaseous mixture can be supplied through the gas distributor 24 in three different ways.
First way provides supply of whole charge of the explosive gaseous mixture through the channel 25 only into the hollow of the heatproof and impact-resistant chamber 1. This way is preferable for thermal-pulse treatment of pieces, which are made from steel or other high- strength materials, for removal of the coarse burrs or tails and/or for strain hardening and smoothing of theirs. Indeed, only in this way the main quantity of the heat and kinetic energy of gaseous explosion products expends for the treatment, and the time, during which the processed pieces are being under the high pressure and high-temperature action, is maximal.
In the second way the charge of the explosive gaseous mixture is supplied through the both channels 25 and 26 synchronously, respectively into the hollow of the heatproof and impact-resistant chamber 1 (for treatment of the processed pieces) and into the air space of the insertion piece 12 (for advance actuation of the spool-type valve). In this way the time during which the processed pieces are being under the high pressure and high-temperature action as less as more explosive gaseous mixture comes into the airspace of the insertion piece 12 through the channel 26. Therefore, such way is preferable to process the pieces, which are made from alloys based on copper, aluminium and magnesium or from reinforced polymeric material based on thermosetting resins.
In the third way the whole charge of the explosive gaseous mixture is supplied through the channel 26 into the airspace of the insertion piece 12. Respectively, the thermal-pulse treatment is provided only by such part of the gaseous explosion products which are passed in time into the hollow of the heatproof and impact-resistant chamber 1 through the opened from the bottom gas-outlet pipe 8. This way of use of thermal and kinetic energy of the gaseous explosion products is expedient if processed pieces are especially sensitive to overheating and detonation. In particular, such treatment is used if processed pieces are made from high-strength (not obligatory reinforced) thermoplastics or rubber. The processing stage starts as flame igniter 5 initiates the explosion of the charge of the gaseous mixture.
If this flame igniter 5 is mounted within said chamber 1 , practically all charge of said mixture detonates in this chamber 1. Respectively, the high-temperature and high-pressure gaseous explosion products will burn the processed pieces to some depth practically instantly; disperse coarse burrs or tails and smooth surfaces of these pieces. However, even in this case raising of the movable damped cover 6 relative to the pneumocylinder casing 21 and respective damping action of air owing to its compression within said pneumocylinder (see Fig.2) must secure such attenuation of impact action of the high-temperature detonation wave on the processed pieces and such decrease of temperature and pressure of the gaseous explosion products within active zone, which must begin practically immediately after ignition of the explosive mixture. Naturally, such "softening" of thermal-pulse treatment will be as more as longer presettable free running of the cover 6 and the piston rod 22.
If the flame igniter 5 is mounted in the outlet of the mixer 2, detonation of the explosive mixture will be initiated before its injection into the channel 25 and/or the channel 26. In this case three different ways of the thermal-pulse treatment is possible.
In the first way the detonating mixture will come into the chamber 1 only through the channel 25, at the outlet of which will be occurred a partial strangling of the gaseous explosion products with respective lowering of their temperature and pressure. Further the gaseous explosion products must expand additionally within the chamber 2 because they expend a significant part of their kinetic energy for raising of the cover 6 and for compression of air within the pneumocylinder casing 21. Aforesaid double strangling of the gaseous explosion products reduces overheating of the processed pieces and contamination of their surface substantially. In the second way the detonating mixture divides into two separate flows. First flow comes in full through the channel 25 into the chamber 1 immediately. The most part of second flow comes at first through the channel 26 into the airspace of the insertion piece 12 and further - through the upper part of the gas-outlet pipe 8 and above-mentioned through- hole of the heatproof and impact-resistant base 7 - into the chamber 1 too. Naturally, such partitioning of the detonating mixture will reduce overheating of the processed pieces and contamination of their surface as more as greater part of said mixture will have been passing through the channel 26.
In the third way all mass of the detonating mixture comes into the airspace of the insertion piece 12 and only then the major portion of the gaseous explosion products comes into the chamber 1 through the upper part of the gas-outlet pipe 8 and the central opening of the base 7. Respectively, in this case impact and thermal action of the detonation wave on the processed pieces is minimal.
The discharging stage begins as the sliding piston 17 would have disengaged from the saddle 16. A time interval between blast initiation of the explosive mixture and said disengagement depends on the initial depth of bringing-in of the centring piece 18 into the gas-outlet pipe 8 and on pressure of the gaseous explosion products above this piece 18. It is clear that said pressure (and speed of down movement of the sliding piston 17) would be as more as greater part of the detonating gaseous mixture had been come into the channel 26. When the centring piece 18 had been gotten out from the gas-outlet pipe 8 and the sliding piston 17 had been sunken, the drain ports 15 will have been opened. Then the throttled spent gaseous explosion products will come into the hollow of the bowl-shaped housing 9 and pass through water layer that will damper additionally an impact loading on the sliding piston 17 and collect all solid fine-dispersed by-products of the thermal-pulse treatment. Finally throttled and refined spent gases come into atmosphere through the exhaust pipe 10 whereas water, which flows through the opened metering valve 14, washes- out obtained aqueous suspension of said solid by-products from the hollow of the housing 9 through the draining fitting 11. Further this suspension comes into not shown settling tank or filter. After the final relief of overpressure, the chamber 1 must be removed from the base 7 and the finished pieces must be evacuated. Then the described above technological process can be repeated.
Industrial Applicability Present machinery plants can manufacture apparatuses according to the invention from available materials and components.
The proposed technology of thermal-pulse treatment provides flexible adjustment of processing conditions (especially, time of action of high-temperature and high-pressure gaseous explosion products upon processed pieces, and dynamic load on equipment's parts) depending on materials and shapes of pieces in order to increase surface quality of finished pieces and operational safety and fail-safety of equipment.