RU2153939C1 - Mortar applying nozzle - Google Patents

Abstract

FIELD: mortar application equipment in construction, coal and other branches of industry. SUBSTANCE: nozzle has body, mortar supplying channel, compressed air supplying channel, and chamber continuously connected to Laval nozzle. Core is positioned inside chamber. Rod is positioned inside core. One end of rod is connected to stem of pneumatic cylinder of unidirectional action and other end is extending into Laval nozzle. Other end of rod is made in the form of truncated cone. Rod is provided with channel serving as pressure sensor. Compressed air is fed from pneumatic system via main through controlled throttle valves. Throttle control member is communicated via main with rod channel. Such construction provides continuous controlling of spray beam section area. Mortar spraying nozzle may be used as module in robotized complexes for applying various coats, in particular, for finishing works in construction industry. EFFECT: increased efficiency, wider operational capabilities and improved quality of coating. 1 dwg

Description

 The invention relates to devices for applying mortar in the air and can be used as a terminal module in robotic complexes for applying various coatings, in particular during finishing work in construction and in other industries.

 The quality of the applied coating depends on the design of the nozzle, the parameters of the solution, the air pressure in the line and, with the characteristics mentioned above unchanged, depends on the constancy of the distance between the outer plane of the nozzle and the surface to be treated. Moreover, the thickness and uniformity of the applied coating also directly depends on the speed of the output stream, and the optimal specified distance depends on all the above factors and is determined by the possibility of strong adhesion of the applied coating to the surface material and coating layers without the formation of sagging, sagging, etc.

 Adjusting the amount of coating applied, and hence the rate of exit of the particles of the solution, can be done by changing the area of the outlet cross section of the nozzle.

 Known technical solutions of nozzles [1,2], which have constant output cross-sectional areas, and as a result of this it is necessary to make increased demands on automatic control systems for coating devices in order to maintain a constant distance from the nozzle to the surface being treated.

 In addition, these designs do not allow to maintain constant the quality of the applied coating when changing technological properties (viscosity, ductility, fluidity, etc.) of the working solution.

 In connection with the need to apply mortars of various plasticities, nozzles with a set of interchangeable tips and holes of different diameters are produced. Therefore, when changing the ductility, viscosity and other properties of the composition, it is necessary to change the tip with the corresponding hole diameter for each type of coating, which increases the time to complete the work and reduces labor productivity. This is due to the impossibility of stepless regulation of the size of the spray torch in existing structures.

 Closest to the claimed technical solution is the nozzle for spraying liquid [3]. Its design is a housing with channels for supplying liquid and gas and a camera passing into the Laval nozzle, in which the central core is placed in the form of a tube, the output end of which is located in the supersonic part of the Laval nozzle. In the core, a rod with a tip is mounted with the possibility of axial movement.

 This design, as well as other manufactured nozzles, has the above-mentioned drawback, which consists in the impossibility of stepless regulation of the size of the annular spray torch when changing the technological properties of the mortar mixture.

где R - радиус трубопровода; l - длина трубопровода; η - вязкость раствора; Δρ - потери давления на трение; Δρ₀ - перепад давления, при котором раствор в трубе радиуса R начинает двигаться.Mortars are classified as elastic-viscous-plastic mixtures ([4], p. 5), the flow rate Q for which is directly proportional to pressure (differential pressure) and inversely proportional to the viscosity of the mixture ([5], formula IV.20, p. 68) :

where R is the radius of the pipeline; l is the length of the pipeline; η is the viscosity of the solution; Δρ - friction pressure loss; Δρ ₀ is the pressure drop at which the solution in the pipe of radius R begins to move.

 Therefore, when changing the viscosity of the solution to maintain its constant flow rate, it is necessary to change the value of air pressure and the area of the annular gap of the spray torch, and the quality of the coating to be applied will be determined by the constancy of their ratio.

 The aim of the present invention is to provide stepless regulation of the inner diameter and cross-sectional area of the spray torch ring, as well as improving the performance of the nozzle and the quality of the coating.

 This goal is achieved by the fact that a device for regulating the area of the annular spray jet installed in the supersonic part of the Laval nozzle and representing a rod, the outlet end of which has a conical shape and the other end is connected to the rod of the pneumatic cylinder, is introduced into the nozzle design. Thus, depending on the plasticity of the mixture, the drag force of the air changes when the solution moves after exiting the nozzle, which is proportional to the square of the particle velocity of the applied mixture and the pressure between the nozzle exit and the surface being treated, which is used as an indicator to maintain the optimal distance to the surface being treated, air pressure in the pressure line and the area of the annular spray torch.

Significant differences of the invention are:
- the implementation of the device for stepless regulation of the diameter and cross-sectional area of the spray torch ring in the form of a rod, the cylindrical part of which is conjugated by means of a conical surface with a spherical outlet end of the rod;
- execution in the core of the channel used as a pressure sensor;
- the use of a single-acting pneumatic cylinder to move the rod;
- installation in front of the piston cavity of the pneumatic cylinder and in the air supply line to the nozzle of adjustable throttles, and the regulating element of the throttle in the air supply line is connected to the rod channel.

 The drawing shows a General view of the nozzle.

 The nozzle contains a housing 1, channels for supplying mortar 2 and compressed air 3, a mixing chamber 4, passing into the Laval nozzle 5. Inside the mixing chamber 4 there is a central core 6 made in the form of a tube, the output end of which is located in the supersonic part of the Laval nozzle 5 A core 7 is mounted in the core 6 with the possibility of axial movement, in which a channel 8 is made, which is used as a pressure sensor. One end of the rod 7 is connected to the rod of a single-acting pneumatic cylinder 9, and the second, having a conical surface, is located in the outlet of the Laval nozzle 5. Compressed air is supplied to the piston cavity of the pneumatic cylinder 9 through an adjustable throttle 10, and into the channel 3 through an adjustable throttle 11, the regulatory element of which is connected by a line 12 to the channel 8 of the rod 7.

 The nozzle works as follows. First, compressed air is supplied to the nozzle through the throttle 11 and channel 3. The working solution enters from a container (not shown) under pressure through a channel 2 into the annular outlet region of the tube 6, formed by its lateral surface and the rod 7. Then, the solution enters through the open end of the tube 6 into the expanding part of the nozzle 5 and is applied onto the annular spray torch the processed surface. In this case, the pressure in the channel 8 is equal to the pressure in the region between the nozzle exit and the surface to be treated, the air flow through the chokes 10 and 11 is constant.

 The rod of the pneumatic cylinder 9 is in a position in which the annular gap has a certain average value determined by the degree of adjustment of the throttle 10. The described case corresponds to the operation of the nozzle with constant pressure in the spray zone on the rod 7 and with a solution mixture of medium ductility.

 With an increase in the plasticity of the solution, there will be an increase in the rate of exit of the jet from the nozzle and, consequently, an increase in the amount of the outgoing mixture and the thickness of the layer of applied coating. Therefore, to obtain a uniform coating and maintain its quality, it is necessary to reduce the distance to the surface to be treated and to reduce the amount of the supplied mixture.

 With an increase in the plasticity of the solution and, in connection with this, the above parameters, the rate of exit of the particles of the solution from the annular gap will increase, which will lead to a simultaneous increase in pressure in the space between the nozzle exit and the treated surface in the channel 8 of the rod 7 and the line 12. In this case, the position of the regulating element will change throttle 11, which will reduce the amount of air supplied to the channel 3 and, consequently, reduce the amount of the nozzle of the solution emerging from the annular gap. The pressure in the piston cavity of the pneumatic cylinder 9 will also decrease, the rod of which will move to the left and reduce the area of the annular gap, which will lead to the restoration of a constant relationship between the parameters included in equation (1) and to an increase in the quality of the applied coating.

 If the nozzle works with solutions with reduced ductility, the jet exit speed will decrease, and to maintain the coating thickness at a constant level, it is necessary to increase the distance to the surface to be treated and also increase the amount of the supplied mixture. Decreasing the rate of solution output will lead to a drop in pressure in channel 8 and line 12 - the regulating element of the throttle 11 will increase the flow rate of air supplied to channel 3, and the pneumatic cylinder 9 will move the rod together with the rod 7 to the right, which will increase the area of the annular spray torch and increase the number applied solution.

 Thus, stepless regulation of the size of the annular spray jet will be carried out depending on changes in the technological properties of the mortar mixture.

Sources of information
1. A. c. USSR 1703186, MKI B 03 B 1/06 Liquid atomizer / S.A. Plum (USSR). Claim 04/18/89; Publ. 01/07/92, Bull. N 1.

 2. A. p. USSR 1713660, MKI B 05 B 1/04 Sprayer / B.E. Katsai, O.V. Khabarov (USSR). Claim 12/27/90; Publ. 02/23/92, Bull. N 7.

 3. A.S. USSR 1514417, MKI B 05 B 7/00, 7/12 Nozzle for spraying liquid / V. A. Vasiliev, Yu.M. Rudov (USSR). Claim 01/11/88; Publ. 10/15/89, Bull. N 38.

 4. Ogibalov P. M., Mirzadzhanzade A.Kh. Unsteady movements of viscoplastic media. Ed. Moscow State University, 1977 .-- 372 p.

 5. Mirzadzhanzade A.Kh., Karaev A.K., Shirinzade S.A. Hydraulics in the drilling and cementing of oil and gas wells.- M .: Nedra, 1977. - 230 p.

Claims (1)

 A nozzle for applying mortar, containing a housing with channels for supplying mortar, compressed air and a chamber passing into the Laval nozzle, with a central core placed in it in the form of a tube, characterized in that a core is installed in the core with axial movement, one the end of which has a conical shape and is located in the Laval nozzle, and its second end is connected to the rod of a single-acting pneumatic cylinder, in the pressure line of the piston cavity of the pneumatic cylinder and the supply channel th mounted adjustable air throttles, wherein the regulating member is connected to the last trunk channel formed in the rod.