CN108333334B - Device and method for measuring relation between concrete pumping pressure and flow - Google Patents
Device and method for measuring relation between concrete pumping pressure and flow Download PDFInfo
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- CN108333334B CN108333334B CN201810028560.6A CN201810028560A CN108333334B CN 108333334 B CN108333334 B CN 108333334B CN 201810028560 A CN201810028560 A CN 201810028560A CN 108333334 B CN108333334 B CN 108333334B
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- 238000005086 pumping Methods 0.000 title claims abstract description 85
- 238000000034 method Methods 0.000 title claims abstract description 26
- 230000001050 lubricating effect Effects 0.000 claims abstract description 31
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- 239000002184 metal Substances 0.000 claims description 3
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Abstract
The invention relates to a device and a method for measuring the relation between concrete pumping pressure and flow, belonging to the technical field of construction engineering. The device comprises a container, a base, a transparent cover plate, a motor, a support frame, a torque sensor and a fan blade type rotor, is simple in structure and convenient to operate, can well simulate a lubricating layer and plug flow in a concrete pumping working condition, measures parameters such as required torque and plug flow radius, and is scientific and reasonable in design. According to the method, the concrete flow field parameters are measured when the container rotates and then are equivalent to the concrete flow field parameters of a lubricating layer and plug flow in concrete pumping, the pumping flow and the pressure loss of concrete are calculated, so that the relation between torque and revolution is converted into the relation between the pumping flow and the pressure loss, a scientific basis is provided for concrete pumping construction through a pumping pressure loss-pumping flow curve, the method is convenient to operate and simple to calculate, and the result is closer to the actual engineering.
Description
Technical Field
The invention relates to a device and a method for measuring the relation between concrete pumping pressure and flow, belonging to the technical field of construction engineering.
Background
In the field of engineering construction, fresh concrete conveying is an important link in structure construction. The modern pumping equipment and technology obviously improve the concrete conveying efficiency, so the concrete conveying device is widely applied to large-scale engineering. During the concrete pumping construction scheme making process, "pumpability" (usually characterized by pumping flow-pressure relationship) is an important content.
In the current industry standard, a pressure loss calculation formula is derived from an empirical formula based on slump indexes and proposed by Morinaga in 1973, and the applicability of the pressure loss calculation formula is questioned along with the development and change of concrete formula and performance. Recent studies have shown that the lubrication-friction effect between the concrete mix and the inner wall of the pump pipe is a major factor affecting pumpability. In low flow concrete, the concrete body moves in a "plug flow" where the shear rate is zero and the shear flow is concentrated in a "lubricating layer" formed near the pipe wall.
Foreign researchers have developed several devices to study the properties of the lubricating layer. These devices, which are mostly of the coaxial rotary type, are mainly characterized by the use of a rotor with a smooth surface, which, when rotating, creates a lubricating layer in the vicinity of the surface. The measurement results of these devices require that the rheological parameters (yield stress and plastic viscosity) of the lubricating layer are derived from the rheological theory and then substituted into a formula related to the pumping situation to estimate the pressure loss, however, the indirect measurement method is easy to generate errors. In addition to the rotary device, there is also a sliding tube type friction resistance meter developed by Putzmeister corporation in germany, which can simulate the pushing of concrete in the pump tube, thereby directly obtaining the pressure-flow relationship, however, in the measurement, the pushing speed is not controlled, and the measurement result and efficiency are affected.
Disclosure of Invention
Aiming at the problems that the error is easy to generate when the existing concrete rheometer simulates a lubricating layer, the pushing speed of a sliding pipe type friction resistance meter is not controlled so as to influence the measuring result and efficiency and the like, the invention provides the device for measuring the relation between the concrete pumping pressure and the flow rate, which has the advantages of simple structure and convenient operation, can better simulate the lubricating layer and the plug flow in the concrete pumping working condition, measures the required parameters such as torque, the plug flow radius and the like, and has scientific and reasonable design. In addition, the invention also provides a method for measuring the relation between the concrete pumping pressure and the flow, the concrete flow field parameters are measured when the container rotates, then the concrete flow field parameters are equivalent to the concrete flow field parameters of a lubricating layer and a plug flow in concrete pumping, the pumping flow and the pressure loss of the concrete are calculated, so that the relation between the torque and the revolution is converted into the relation between the pumping flow and the pressure loss, a scientific basis is provided for concrete pumping construction through a pumping pressure loss-pumping flow curve, the method is convenient to operate and simple to calculate, and the result is closer to the actual engineering.
In order to solve the technical problems, the invention comprises the following technical scheme:
an apparatus for determining the relationship between concrete pumping pressure and flow rate, comprising:
the container is used for containing concrete to be tested and is made of an inner layer sample of a pump pipe, and the bottom of the container is provided with an external thread;
the middle part of the base is provided with a U-shaped groove, an internal thread matched with the external thread is arranged in the groove, and the container is embedded in the groove and is in threaded connection with the base;
the transparent cover plate is detachably connected with the top of the container, and a shaft hole is formed in the axis;
the motor is connected with the base and can drive the base and the container to rotate;
the supporting frame is arranged outside the container and spans the top of the container;
the torque sensor is fixed on the support frame and is positioned right above the container; and the number of the first and second groups,
the fan blade type rotor comprises a rotating shaft and a plurality of blades fixedly connected to the rotating shaft, the blades are located in the container, the rotating shaft penetrates through a shaft hole of the transparent cover plate and is connected with the torque sensor, and the fan blade type rotor and the container are coaxial.
Preferably, the device further comprises a base, the base is located below the base, and the motor is located in the base.
Preferably, the support frame comprises a plurality of vertical rods, connecting rods fixedly connected with the vertical rods, and a tray which is positioned right above the shaft holes of the transparent cover plate and fixedly connected with the other ends of the connecting rods;
the tray is provided with a through hole for the rotating shaft to pass through, and the torque sensor is fixed on the tray.
Preferably, the connecting rod and the vertical rod can be fixed in one of the following manners:
a. the connecting rod is fixed on the vertical rod through a pipe hoop.
b. The connecting rod is characterized in that a plurality of bolt holes are formed in the vertical rod, an internal thread is arranged at one end of the connecting rod, and the connecting rod is fixed to the vertical rod through bolts penetrating through the bolt holes.
Preferably, the top of the container is provided with external threads, the transparent cover plate is provided with internal threads, and the transparent cover plate is in threaded connection with the top of the container.
Preferably, the upper surface of the transparent cover plate is provided with a graduated scale along the radius direction from the center of a circle.
Preferably, a rubber ring for preventing concrete from seeping out is provided between the container and the base.
Preferably, the base is made of metal, and polishing treatment is carried out in the groove.
Correspondingly, the invention also provides a method for measuring the relation between the concrete pumping pressure and the flow by using the device, which is characterized by comprising the following steps:
s1, pouring fresh concrete to a height of h and an inner diameter of r0The container is covered with a transparent cover plate;
s2, starting a motor, driving the base and the container to rotate at a certain rotating speed N, wherein the angular speed of the container is omega-2 pi N, and the linear speed is v0＝ωro＝2πNro；
S3, after the concrete is rotated stably, the concrete close to the inner wall of the container rotates, the concrete close to the central area of the container does not rotate, and the rotating speed v isp0; measuring radius r of non-rotating areapReading the reaction torque T borne by the fan blade type rotor by a torque sensor;
s4, rotating the container and the vane type rotor, equivalently, rotating the container and the vane type rotor, thereby simulating the concrete pumping working condition, wherein the concrete in the rotating area in the container is equivalently a lubricating layer in concrete pumping, and the concrete in the non-rotating area is equivalently plug flow in the concrete pumping; in the container, the concrete plug flow radius is rpThe torque acting on the plug flow is T; after equivalence, flow in plug flow zoneV 'of'p＝v0＝2πNro(ii) a The inner diameter of the region of the lubricating layer being rpOuter diameter of r0And r ispHas a flow velocity of v'p、r0Has a flow velocity of v'0＝vpThe flow speed of the lubricating layer is approximately assumed to be in a linear relation with the radius; from the area of the plug flow concrete flow Q1And the concrete flow Q of the lubricating layer area2Concrete pumping flow Q can be obtained, which is specifically referred to as a formula I; wherein,
s5, assuming that the pressure at the bottom of the micro element of the equivalent pump pipe of the container is P + dp and the pressure at the top is P, a formula II can be obtained according to the balance relation, and the pumping pressure loss P caused by the friction of the concrete can be obtained by combining the formula II according to the actual length L of the pump pipe in the concrete pumpingsThe calculation formula (c) of (a), wherein,
where dp is the differential of the pressure loss, τoIs the shear stress to which the inner wall of the vessel is subjected, dL is the differential of the vessel length;
s6, repeating the steps S2 to S5, and obtaining the pressure loss P of the corresponding multiple groups of concrete pumping by changing the torque T and the revolution NSThe pumping flow Q, and drawing PSAnd (5) a Q curve, and establishing a pumping construction scheme.
Preferably, the formula one is simplified as:
Q≈Q1＝πrp 2v0＝πrp 2·2πNro。
the invention provides a device for measuring the relation between concrete pumping pressure and flow, which is characterized in that a container is used for containing concrete mixture to be measured, a base and the container are driven to rotate by a motor, under the action of friction force of the inner wall of the container, the concrete tightly attached to the inner wall of the container synchronously rotates with the container, under the drive of the viscous force of the concrete, the concrete close to the inner wall of the container with a certain thickness also rotates, only a thin layer of concrete rotates due to the fact that the viscous force of the concrete is smaller and a fan blade type rotor forms obstruction to the rotation of the concrete, the rotating concrete layer is equivalent to a lubricating layer in concrete pumping, and the concrete layer which does not rotate close to the center of the container is equivalent to plug flow in the concrete pumping, so the device can simulate the plug flow and the lubricating layer in the concrete pumping. In the invention, the inner layer sample of the pump pipe is directly made into the container, so that the measurement result is more accurate. The torque sensor is connected with the fan blade type rotor, and the fan blade type rotor is arranged at the axis of the container and can be used for measuring the torque applied to the concrete in the non-rotation area in the container. Therefore, the device for measuring the relation between the concrete pumping pressure and the flow is simple in structure and convenient to operate, can better simulate a lubricating layer and plug flow in the concrete pumping working condition, and can measure parameters such as required torque and plug flow radius, and the device is scientific and reasonable in design.
The method for determining the relation between the pumping pressure and the flow of the concrete, provided by the invention, comprises the steps of pouring fresh concrete into a container of the device in the first embodiment, starting a motor to rotate at the revolution number N, measuring the radius of a concrete interface in the container and the torque value of a torque sensor, equating concrete flow field parameters when the container rotates as the situation when the container does not rotate, and calculating the pumping flow and the pressure loss of the concrete, so that the relation between the torque and the revolution number is converted into the relation between the pumping flow and the pressure loss, and a scientific basis is provided for concrete pumping construction through a pumping pressure loss-pumping flow curve.
Drawings
FIG. 1 is a schematic structural diagram of a device for measuring a relation between a pumping pressure and a flow rate of a concrete according to an embodiment of the present invention;
FIG. 2 is a schematic view of a container rotating in another embodiment of the present invention;
FIG. 3 is a schematic view of flow field parameters of concrete in another embodiment of the present invention;
FIG. 4 is a schematic view of equivalent concrete flow field parameters in another embodiment of the present invention;
fig. 5 is a schematic diagram of the pressure balance relationship of the equivalent concrete in another embodiment of the invention.
The numbers in the figures are as follows:
1-a container; 2-a base; 3-a transparent cover plate; 4-a motor; 5-a support frame; 51-a vertical bar; 52-a connecting rod; 53-tray; 6-a torque sensor; 7-a fan blade type rotor; 71-a rotating shaft; 72-a blade; 8-a base; 9-concrete.
Detailed Description
The following describes in detail a device and a method for measuring a relation between a pumping pressure and a flow rate of a concrete according to the present invention with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent when considered in conjunction with the following description and claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Example one
Referring to fig. 1, the apparatus for measuring a relation between a pumping pressure and a flow rate of a concrete according to the present embodiment includes a container 1, a base 2, a transparent cover plate 3, a motor 4, a support frame 5, a torque sensor 6, and a fan blade type rotor 7.
Wherein, container 1 is used for holding concrete 9 that awaits measuring, adopts pump line inlayer sample to make, directly makes container 1 with pump line inlayer sample, can make measuring result more accurate. The middle part of the base 2 is provided with a U-shaped groove, and the bottom end of the container 1 is embedded into the groove. In order to tightly connect the base 2 and the container 1 and prevent concrete slurry from overflowing, the bottom end of the container 1 is provided with an external thread, an internal thread matched with the external thread is arranged in the groove, and the base 2 is in threaded connection with the container 1. In order to prevent concrete from overflowing from the connection between the base 2 and the container 1, a rubber ring for preventing concrete from seeping out is preferably provided between the container 1 and the base 2.
In order to avoid the influence on the measurement result caused by the friction between the bottom of the groove of the base 2 and the lower surface of the transparent cover plate 3 and the concrete, it is preferable that the bottom of the groove of the base 2 and the upper surface of the transparent cover plate 3 have smooth surfaces, for example, the base 2 is made of metal and the groove is polished, the transparent cover plate 3 is made of PVC plastic and has a transparent and smooth surface, and certainly, a lubricant or a release agent can be coated in the groove of the base 2 and the lower surface of the transparent cover plate 3, so as to reduce the friction with the concrete and the influence on the measurement result.
The motor 4 is connected to the base 2 and drives the base 2 and the container 1 to rotate. The connection between the motor 4 and the base 2 can be various, such as a gear transmission, a belt transmission, a chain transmission, etc., and is not limited herein.
The support frame 5 is arranged outside the container 1 and spans the top of the container 1, and is mainly used for fixing the torque sensor 6 right above the container 1. The support frame 5 may have various structures, such as a rod member on which the torque sensor 6 is fixed, or the support frame 5 may be an inverted transparent cover on top of which the torque sensor 6 is fixed. In a preferred embodiment, the supporting frame 5 includes a plurality of vertical rods 51, a connecting rod 52 fixedly connected with the vertical rods 51, and a tray 53 located right above the axial hole of the transparent cover plate 3 and fixedly connected with the other end of the connecting rod 52, a through hole is arranged at the axial center of the tray 53, and the torque sensor 6 is fixed on the tray 53. Further, the fixing height of the connecting rod 52 on the vertical rod 51 can be adjusted, and preferably, the fixing manner of the connecting rod 52 and the vertical rod 51 can adopt one of the following manners: a. the connecting rod 52 is fixed on the vertical rod 51 through a pipe hoop; b. the vertical rod 51 is provided with a plurality of bolt holes, one end of the connecting rod 52 is provided with internal threads, and the connecting rod 52 is fixed on the vertical rod 51 through bolts penetrating through the bolt holes.
In a preferred embodiment, as shown in fig. 1, the device further comprises a base 8, and the motor 4 is located in the base 8. More preferably, the support frame 5 is fixed to the base 8. So design, the device has better wholeness, and the structure is more firm.
The fan-shaped rotor 7 comprises a rotating shaft 71 and a plurality of blades 72 fixedly connected on the rotating shaft 71, the blades 72 are positioned in the container 1, the rotating shaft 71 penetrates through the shaft hole of the transparent cover plate 3 and the through hole of the tray 53 to be connected with the torque sensor 6, and the fan-shaped rotor 7 and the container 1 are coaxial.
The invention provides a device for measuring the relation between concrete pumping pressure and flow, which is characterized in that a container 1 is used for containing a mixture of concrete 9 to be measured, a motor 4 is used for driving a base 2 and the container 1 to rotate, under the action of friction force of the inner wall of the container 1, the concrete tightly attached to the inner wall of the container 1 synchronously rotates with the container, under the drive of concrete viscous force, the concrete with a certain thickness close to the inner wall of the container 1 also rotates, because the viscous force of the concrete is smaller and a fan-blade rotor 7 forms obstruction to the rotation of the concrete, only a thin layer of concrete rotates, the rotating concrete layer is equivalent to a lubricating layer in concrete pumping, and the concrete layer which does not rotate close to the center of the container 1 is equivalent to plug flow in the concrete pumping, so the device can simulate plug flow and the lubricating layer in the concrete pumping. In the invention, the inner layer sample of the pump pipe is directly made into the container 1, so that the measurement result is more accurate. The torque sensor 6 is connected with a fan-shaped rotor 7, and the fan-shaped rotor 7 is arranged at the axis of the container 1 and can be used for measuring the torque applied to the concrete in the non-rotating area of the container 1. Therefore, the device for measuring the relation between the concrete pumping pressure and the flow is simple in structure and convenient to operate, can better simulate a lubricating layer and plug flow in the concrete pumping working condition, and can measure parameters such as required torque and plug flow radius, and the device is scientific and reasonable in design.
Example two
The present embodiment provides a method for determining the relationship between the pumping pressure and the flow rate of concrete by using the device in the first embodiment, which is further described with reference to fig. 1 to 5. The method specifically comprises the following steps:
s1, pouring fresh concrete 9 to a height of h and an inner diameter of r0The container 1 is covered with a transparent cover plate 3;
s2, with reference to fig. 2 and 3, the motor 4 is started to rotate the base 2 and the container 1 at a certain rotation speed N, the angular velocity of the container 1 is ω -2 pi N, and the linear velocity is v0＝ωro＝2πNro。
S3, as shown in figure 3, after the concrete is rotated stably, the concrete close to the inner wall of the container 1 rotates, the concrete close to the central area of the container 1 does not rotate, and the rotating speed v p0; measuring radius r of non-rotating areapAnd the torque sensor 6 reads the reaction torque T borne by the fan blade type rotor 7.
As shown in FIG. 3, under the action of the friction force on the inner wall of the container 1, the concrete clinging to the inner wall of the container 1 rotates synchronously therewith, and the linear velocity v0＝ωro＝2πNroUnder the drive of the viscous force of the concrete, the concrete with a certain thickness close to the inner wall of the container 1 also rotates, because the viscous force of the concrete is smaller and the fan-shaped rotor 7 forms a barrier to the rotation of the concrete, only a thin layer of concrete rotates, the concrete close to the central area of the container 1 does not rotate, namely, the rotating speed v is not rotatedp0. The linear velocity of the concrete in the rotating area is determined by the inner wall (radius r) of the container 10V of (a) to (b)0＝ωro＝2πNroGradually decrease to vp0 (radius r)pAt (c).
S4, combining the drawings shown in figures 3 and 4, rotating the container 1 and not rotating the fan blade type rotor 7, which is equivalent to the rotation of the container 1 and not rotating the fan blade type rotor 7, thereby simulating a concrete pumping workerThe conditions are as follows; the concrete in the rotating area in the container 1 is equivalent to a lubricating layer in concrete pumping, and the concrete in the non-rotating area is equivalent to plug flow in the concrete pumping; in the container, the concrete plug flow radius is rpThe torque acting on the plug flow is T; after equivalence, flow velocity v 'in plug flow region'p＝v0＝2πNro(ii) a The inner diameter of the region of the lubricating layer being rpOuter diameter of r0And r ispHas a flow velocity of v'p、r0Has a flow velocity of v'0＝vpThe flow speed of the lubricating layer is approximately assumed to be in a linear relation with the radius; from the area of the plug flow concrete flow Q1And the concrete flow Q of the lubricating layer area2Concrete pumping flow Q can be obtained, which is specifically referred to as a formula I; wherein,
fig. 3 is a schematic diagram of concrete flow field parameters before equivalence, and fig. 4 is a schematic diagram of concrete flow field parameters after equivalence. Concrete flow velocity v 'of equivalent plug flow (grey area in FIG. 4) area as shown in FIG. 4'p＝v0＝2πNro(ii) a Region of lubricating layer (r)pTo r0Annular region in between) of v'pIs gradually reduced to v'0＝v p0. Assuming a linear relationship between the flow rate and the radius of the lubricant layer, one can deduce
The concrete flow Q of the plug flow area can be deduced from the flow speed and the area1＝πrp 2v0And can deduce the concrete flow in the lubricating layer
So as to deduce the pumping flow Q-Q1+Q2. It should be noted that the curve of the flow velocity of the lubricant layer along with the change of the radius is a parabola, and is simplified into a straight line for the convenience of calculation, and the simplification has little influence on the result.
Because the lubricating layer area is very thin, the influence on the concrete flow in the pump pipe is small, and meanwhile, the concrete flow Q in the lubricating layer area can be ignored on the basis of the conservation principle in the engineering2Thus, equation one can be simplified to Q ≈ Q1＝πrp 2v0＝πrp 2·2πNro。
S5, as shown in figure 5, assuming that the pressure at the bottom of the equivalent pump pipe microcell of the container 1 is P + dp and the pressure at the top is P, a formula II can be obtained according to the balance relation, and the pumping pressure loss P caused by the friction of the concrete can be overcome by combining the formula II according to the actual length L of the pump pipe in concrete pumpingsThe calculation formula (c) of (a), wherein,
where dp is the differential of the pressure loss, τodL is the differential of the length of the vessel 1, the shear stress to which the inner wall of the vessel 1 is subjected.
The torque at the inner wall of the container 1 is T, and the stress of the inner wall of the equivalent rear pump pipe can be derived to
Shear force F2 pi r on the inner wall with length dLo·τodL, from which the pressure loss is derived
S6, repeating the steps S2 to S5, and obtaining the pressure loss P of the corresponding multiple groups of concrete pumping by changing the torque T and the revolution NSThe pumping flow Q, and drawing PSAnd Q, pumping flow curve and establishing a pumping construction scheme.
In summary, according to the method for determining the relation between the pumping pressure and the flow rate of the concrete provided by the invention, fresh concrete 9 is poured into the container 1 of the device in the first embodiment, the motor 4 is started to rotate at the revolution number N, then the radius of the concrete interface in the container 1 and the torque value of the torque sensor 6 are measured, the concrete flow field parameters when the container 1 rotates are equivalent to the situation when the container 1 does not rotate, then the pumping flow rate and the pressure loss of the concrete are calculated, so that the relation between the torque and the revolution number is converted into the relation between the pumping flow rate and the pressure loss, and a scientific basis is provided for concrete pumping construction through a pumping pressure loss-pumping flow rate curve.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (8)
1. A method for measuring the relation between the pumping pressure and the flow rate of concrete is characterized in that,
the method is carried out by utilizing a device for measuring the relation between the pumping pressure and the flow of the concrete, and the device comprises the following steps:
the container is used for containing concrete to be tested and is made of an inner layer sample of a pump pipe, and the bottom of the container is provided with an external thread;
the middle part of the base is provided with a U-shaped groove, an internal thread matched with the external thread is arranged in the groove, and the container is embedded in the groove and is in threaded connection with the base;
the transparent cover plate is detachably connected with the top of the container, and a shaft hole is formed in the axis; a graduated scale is arranged on the upper surface of the transparent cover plate along the radius direction from the circle center;
the motor is connected with the base and can drive the base and the container to rotate;
the supporting frame is arranged outside the container and spans the top of the container;
the torque sensor is fixed on the support frame and is positioned right above the container; and the number of the first and second groups,
the fan-blade type rotor comprises a rotating shaft and a plurality of blades fixedly connected to the rotating shaft, the blades are positioned in the container, the rotating shaft penetrates through a shaft hole of the transparent cover plate to be connected with the torque sensor, and the fan-blade type rotor and the container are coaxial and have the same height;
the method comprises the following steps:
s1, pouring fresh concrete to a height of h and an inner diameter of r0The container is covered with a transparent cover plate;
s2, starting a motor, driving the base and the container to rotate at a certain rotating speed N, wherein the angular speed of the container is omega-2 pi N, and the linear speed is v0＝ωro＝2πNro；
S3, after the concrete is rotated stably, the concrete close to the inner wall of the container rotates, the concrete close to the central area of the container does not rotate, and the rotating speed v isp0; measuring radius r of non-rotating areapReading the reaction torque T borne by the fan blade type rotor by a torque sensor;
s4, rotating the container and the vane type rotor, equivalently, rotating the container and the vane type rotor, thereby simulating the concrete pumping working condition, wherein the concrete in the rotating area in the container is equivalently a lubricating layer in concrete pumping, and the concrete in the non-rotating area is equivalently plug flow in the concrete pumping; in the container, the concrete plug flow radius is rpThe torque acting on the plug flow is T; after equivalence, flow velocity v 'in plug flow region'p＝v0＝2πNro(ii) a The inner diameter of the region of the lubricating layer being rpOuter diameter of r0And r ispHas a flow velocity of v'p、r0Has a flow velocity of v'0＝vpThe flow speed of the lubricating layer is approximately assumed to be in a linear relation with the radius; from the area of the plug flow concrete flow Q1And the concrete flow Q of the lubricating layer area2Concrete pumping flow Q can be obtained, which is specifically referred to as a formula I; wherein,
s5, assuming that the pressure at the bottom of the micro element of the equivalent pump pipe of the container is P + dp and the pressure at the top is P, a formula II can be obtained according to the balance relation, and the pumping pressure loss P caused by the friction of the concrete can be obtained by combining the formula II according to the actual length L of the pump pipe in the concrete pumpingsThe calculation formula (c) of (a), wherein,
where dp is the differential of the pressure loss, τoIs the shear stress to which the inner wall of the vessel is subjected, dL is the differential of the vessel length;
s6, repeating the steps S2 to S5, and obtaining the pressure loss P of the corresponding multiple groups of concrete pumping by changing the torque T and the revolution NSThe pumping flow Q, and drawing PSAnd (5) a Q curve, and establishing a pumping construction scheme.
2. The method of claim 1, wherein in step S3, formula one is simplified as:
Q≈Q1＝πrp 2v0＝πrp 2·2πNro。
3. the method of claim 1, wherein the device further comprises a base, wherein the base is positioned below the base, and wherein the motor is positioned within the base.
4. The method of claim 1,
the supporting frame comprises a plurality of vertical rods, connecting rods fixedly connected with the vertical rods, and a tray which is positioned right above the shaft holes of the transparent cover plate and fixedly connected with the other ends of the connecting rods;
the tray is provided with a through hole for the rotating shaft to pass through, and the torque sensor is fixed on the tray.
5. The method of claim 4, wherein the connecting rod is fixed to the vertical rod by one of:
a. the connecting rod is fixed on the vertical rod through a pipe hoop;
b. the connecting rod is characterized in that a plurality of bolt holes are formed in the vertical rod, an internal thread is arranged at one end of the connecting rod, and the connecting rod is fixed to the vertical rod through bolts penetrating through the bolt holes.
6. The method of claim 1,
the container top is provided with the external screw thread, transparent cover is provided with the internal thread, transparent cover with container top threaded connection.
7. A method according to claim 1, wherein a rubber ring for preventing concrete seepage is provided between the container and the base.
8. The method of claim 1, wherein the base is made of metal and the recess is polished.
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| DE102019108781A1 (en) | 2019-04-03 | 2020-10-08 | Peri Gmbh | Computer-aided method and device for optimized control of the delivery rate of a concrete pump or the like |
| CN110161219A (en) * | 2019-05-31 | 2019-08-23 | 中冶建工集团有限公司 | Judge the method and device of grouting material fluidity |
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| CN2569143Y (en) * | 2002-09-24 | 2003-08-27 | 天津大学 | Concrete rheometer |
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| CN2569143Y (en) * | 2002-09-24 | 2003-08-27 | 天津大学 | Concrete rheometer |
Non-Patent Citations (3)
| Title |
|---|
| Prediction of pumping pressure by means of new tribometer for highly-workable concrete;Dimitri Feys，et al.;《Cement & Concrete Composites》;20141224;第57卷;第102-105页 * |
| State of the Art on Prediction of Concrete Pumping;Seung Hee Kwon, et al;《International Journal of Concrete Structures and Materials》;20160616;第10卷(第3期);第S76-78页 * |
| 泵送混凝土易泵性试验评价方法的研究进展;赵 筠;《混凝土世界》;20140430(第58期);第44-53页 * |
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