Stacked spiral sludge dewatering machine and control method thereof

Abstract

The invention provides a stacked screw type sludge dewatering machine and a control method thereof. The method comprises the following steps: monitoring the real-time rotation speed W (t) of a screw shaft and the real-time sludge flow velocity v (t) from a sludge inlet to a sludge outlet of a stacked screw dewatering box in real time; further calculating the vertical radial change distance of the moving ring; calculating the stress conditions of the upper and lower surfaces of the spiral blade and the spiral shaft in the spiral shaft area, and further respectively obtaining the thrust and lifting force of the X axis and the Z axis to the sludge in the body coordinate system; solving the optimal real-time sludge flow rate enabling the water filtering amount to be maximum; and under the control of the optimal real-time sludge flow rate, judging whether the water content of the dewatered sludge at the sludge discharge port is within the threshold range of the water content of the dewatered sludge, and further selecting whether to treat the sludge at the updated optimal real-time sludge flow rate. Sludge entering the stacked spiral dewatering box can be controlled to enter the stacked spiral dewatering box at the optimal real-time sludge flow speed, so that the maximum water filtering amount is achieved while floccules are prevented from being damaged in the spiral propelling dewatering process, the dewatering efficiency is remarkably improved, and the water content of the dewatered sludge is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment, and in particular relates to a screw stack type sludge dewatering machine and a control method thereof. Background Art

[0002] In the process of treating urban sewage or industrial sewage, a large amount of sludge will be produced. Sludge concentration, sludge stabilization and sludge dewatering are the most widely used treatment and disposal technologies in my country's sewage treatment plants. Among them, sludge dewatering is one of the important links in sewage treatment. Its main purpose is to remove water from the sludge, so that the moisture content of the sludge after dehydration is reduced, which is convenient for subsequent treatment and disposal (such as landfill, incineration, composting, etc.); in terms of sludge dewatering, the measures taken by my country are mainly mechanical dewatering, and its equipment mainly includes screw dewatering machine, belt filter press, centrifugal filter and plate and frame filter press. However, in small and medium-sized sludge treatment projects, the operation cost of belt filter press, centrifugal filter and plate and frame filter press to treat sludge is high, the energy consumption is high, the working environment is poor and the treatment effect is difficult to guarantee.

[0003] The screw stack sludge dewatering machine is a new type of dewatering equipment based on "spiral extrusion + multi-stage filtration". It is suitable for various scenarios such as municipal sewage treatment plants and industrial sludge treatment. For example, the screw stack sludge dewatering machine disclosed in the invention patent application documents with application numbers CN202211387045.X and CN202211468112.0 in the prior art adopts a superimposed structure of a fixed ring and a movable ring. The sludge is gradually compressed and dehydrated under the push of the spiral shaft. The high moisture content of the dehydrated sludge removed by the screw stack sludge dewatering machine has always been an insurmountable technical difficulty. The current equipment usually reaches a moisture content of 70%-85%, but in some special scenarios, the moisture content needs to be further reduced because the wastewater to be treated will have large fluctuations depending on the season and process. Therefore, some manual adjustments are required in different seasons to reduce the moisture content. According to the different initial moisture content, the flow rate of the sludge entering the screw stack dewatering box, the speed of the spiral shaft, and the amount of flocculant added are manually adjusted. Therefore, how to achieve the dehydration efficiency and mud cake quality of the screw stack sludge dewatering machine through remote PLC central control while reducing manual maintenance operations, and provide an economical, environmentally friendly, and efficient intelligent automated screw stack dewatering machine and its control method for sludge treatment is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above-mentioned defects, the present invention provides a screw stack sludge dewatering machine and a control method thereof. The present invention can reveal important mechanical behaviors in the sludge dewatering process by analyzing the eccentric motion trajectory of the dynamic ring and the shear stress of the spiral blades in the spiral shaft area, significantly improve the dewatering efficiency of the screw stack sludge dewatering machine, reduce the moisture content of the sludge after dehydration, and extend the service life of the equipment, thereby providing a guarantee for achieving the economic and environmental benefits of sludge treatment.

[0005] The present invention provides the following technical solution: a control method for a screw stack sludge dewatering machine, the method is used to control the sludge as a flocculant mixture entering the screw stack dewatering box to enter at an optimal real-time sludge flow rate, thereby avoiding the flocculants from being destroyed during the screw propulsion dewatering process while achieving the maximum water filtration amount, the method comprising:

[0006] S1: real-time monitoring of the real-time rotation speed W(t) of the screw shaft and the real-time sludge flow rate v(t) from the sludge inlet to the sludge outlet (20) of the screw stack dewatering box;

[0007] S2: Construct a calculation formula for the real-time eccentric distance of the moving ring relative to the initial position at the axial position of the y-axis of the three-dimensional coordinate system of different spiral axes, and further calculate the vertical radial change distance of the moving ring;

[0008] S3: Calculate the forces on the upper and lower surfaces of the spiral blades and the spiral shaft in the spiral shaft area separated by two adjacent spiral blades, and then obtain the X-axis thrust F on the sludge in the body coordinate system X and Z-axis lifting force F on sludge Z ;

[0009] S4: Under the condition that the sludge is subjected to uniform force in different spiral axis areas, the optimal real-time sludge flow rate that maximizes the filtered water volume is solved;

[0010] S5: Under the control of the optimal real-time sludge flow rate, further determine whether the moisture content of the dehydrated sludge at the sludge discharge port is within the threshold range of the moisture content of the dehydrated sludge. If so, maintain the optimal real-time sludge flow rate at this time; otherwise, repeat the above steps to process the sludge with the updated optimal real-time sludge flow rate.

[0011] Furthermore, the S2 step includes:

[0012] S21: Calculate the axial distance of the spiral rod along the axial direction of the spiral axis in the spiral axis region where the i-th spiral blade is located in the three-dimensional coordinate system of the spiral axis:

[0013] Where K is the nonlinear pitch variation index, L is the length of the entire spiral axis along the y-axis in the three-dimensional coordinate system of the spiral axis, y∈(0,L]; i=1,2,…N; N+1 is the total number of spiral blades on the spiral axis; B i Represents the y-axis in the three-dimensional coordinate system of the spiral axis i The center point of the i-th spiral blade at the spiral axis is y i+1 The axial distance between the center points of the i+1th spiral blades on the y axis; i ∈[0,L],y i+1 ∈[0,L],y i+1 >yi ; When the treated sludge is municipal sludge, K = 0.8 ~ 1.2; when the treated sludge is industrial sludge, K = 1.2 ~ 1.5;

[0014] S22: Calculate the radius r(y) of the spiral axis at the ordinate in the three-dimensional coordinate system of different spiral axes:

[0015] Wherein, D is the radius variation index of the spiral axis, D = 1.15 ~ 1.35;

[0016] S23: Construct the mth i The real-time eccentric distance of the moving ring relative to the initial position of the screw axis in the three-dimensional coordinate system The calculation formula is:

[0017] mth i The first dynamic ring is located between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade, m i =1,2,…M i , M i is the total number of dynamic rings between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade, that is, the total number of dynamic rings in the i-th spiral axis region separated by the spiral blades, and the i-th spiral axis region is the axial region between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade; A i is the axial distance from the starting end to the ending end of the i-th spiral blade along the axial direction of the spiral shaft,

[0018] The vertical coordinate is in the three-dimensional coordinate system of the spiral axis. The mth i The eccentric motion amplitude of the moving ring is c is the radius difference between the outer circumference of each moving ring and the outer circumference of the fixed ring; r s is the radius of the outer wall of the moving ring; W(t) is the real-time rotation speed of the screw shaft obtained by real-time monitoring in step S1;

[0019] S24: Calculate the mth i The radial variation of the vertical distance along the z-axis in the three-dimensional coordinate system of the spiral axis of the moving ring

[0020] in, For m i The eccentricity angle of the moving ring relative to the axis of the initial position;

[0021] Furthermore, the S3 step includes:

[0022] S31: Calculate the mth i The shear stress between the surface of the spiral blade in the tangential direction of the spiral blade and the sludge pushed by it and mth i The shear stress of the spiral shaft surface in the spiral shaft area where the spiral blades are located in the tangential direction of the spiral blades and the shear stress that drives the sludge flow

[0023] v α (t) is the flow velocity of sludge in the tangential direction of the spiral blade, v α (t) = v(t) arcsinθ; σ is the viscosity coefficient of the sludge entering the screw dewatering box, σ = 0.01 ~ 0.5 Pa·s;

[0024] S32: Calculate the mth i The shear stress between the surface of the spiral blade in the axial direction of the spiral blade and the sludge pushed by it mth i The shear stress of the spiral shaft surface in the spiral shaft area where the spiral blades are located in the axial direction of the spiral blades and the shear stress that drives the sludge flow

[0025] S33: According to the calculation results of step S31 and step S32, further calculate the mth i The thrust of the spiral blade surface on the sludge in the X-axis direction in the body coordinate system and Z-axis thrust

[0026]

[0027] Wherein, θ is the helix angle of the spiral blade; γ is the inclination angle of the spiral axis relative to the horizontal plane of the body coordinate system;

[0028] S34: mth i The thrust of the spiral shaft surface in the spiral shaft area where the spiral blades are located on the sludge in the X-axis direction in the body coordinate system and Z-axis thrust

[0029]

[0030] S35: According to the calculation results of step S33 and step S34, further calculate the X-axis thrust F of the sludge in the body coordinate system X and Z-axis lifting force F on sludge Z :

[0031]

[0032] Furthermore, the step S32 includes the following steps:

[0033] S321: Construct an equation between the pressure gradient of the sludge flow in the y-axis direction of the spiral axis three-dimensional coordinate system and the sludge flow velocity v(t):

[0034]

[0035] Where p(t) is the real-time pressure of sludge on the surface of spiral shaft and spiral blade; v β (t) is the flow velocity of sludge in the axial direction of the spiral blade, v β (t) = v(t)arccosθ;

[0036] S322: Further solve the equation constructed in step S321 and The first-order derivative of the boundary conditions is obtained, and then the calculation of the mth i The shear stress between the surface of the spiral blade in the axial direction of the spiral blade and the sludge pushed by it mth i The shear stress of the spiral shaft surface in the spiral shaft area where the spiral blades are located in the axial direction of the spiral blades and the shear stress that drives the sludge flow

[0037]

[0038] in, is the real-time pressure gradient of sludge on the spiral blade surface, is the real-time pressure gradient of sludge on the surface of the spiral shaft;

[0039]

[0040] S323: Then solve and get the mth i The shear stress between the surface of the spiral blade in the axial direction of the spiral blade and the sludge pushed by it mth i The shear stress of the spiral shaft surface in the spiral shaft area where the spiral blades are located in the axial direction of the spiral blades and the shear stress that drives the sludge flow

[0041]

[0042] Furthermore, the S4 step includes:

[0043] S41: Calculate the total amount of sludge Q that is processed by the screw shaft during one rotation period T of the screw shafttotal , the amount of filtered water generated by the screw dewatering box treating the sludge Q water :

[0044]

[0045] Wherein, s is the first gap distance between the moving ring and the static ring of each moving and static ring combination, s=0.2mm~1.0mm; t represents the time t; t∈[t0,t0+T], t0 is the starting time of a rotation cycle;

[0046] S42: Construct the limiting equation for the balance between lifting force and sludge discharge within the cycle to solve the optimal real-time sludge flow rate:

[0047] Q total -Q water =η(F z -Q waterρout ) / ρ, where ρ is the sludge density, η is the screw shaft transmission efficiency coefficient, η = 0.7 ~ 0.9; ρ out is the density of the escaped water, ρ out =1.00~1.10g / cm 3 ;

[0048] And construct the pressure gradient steady-state equation to solve the optimal real-time sludge flow rate:

[0049] in, is the gradient calculation symbol; ρ is the density of the sludge produced by the reaction of the sewage entering the flocculation tank with the flocculant, ρ = 1.01 ~ 1.10 g / cm 3 ;

[0050] S43: Under the constraints of the equilibrium limiting equation and the pressure gradient steady-state equation constructed in step S42, solve the water filtering amount Q within one spiral shaft rotation cycle water Maximum optimal real-time sludge flow rate v best (t):

[0051]

[0052] Furthermore, in the step S5, after one cycle of sludge dehydration at the optimal real-time sludge flow rate, the moisture content of the dehydrated sludge at the sludge outlet is W final The calculation formula is as follows:

[0053] Wherein, W0 is the initial moisture content of the sludge after being mixed with the flocculant at the mud inlet of the spiral dewatering box, W0=90%~95%.

[0054] Furthermore, the threshold value range of the moisture content of the dehydrated sludge is 60% to 80%.

[0055] The present invention also provides a screw stack type sludge dewatering machine using the above method, the dewatering machine comprises a flocculation box, a screw stack dewatering box, the sludge inlet of the screw stack dewatering box is connected with the sludge outlet of the flocculation box through a sludge inflow pipe; the flocculation box is fixedly arranged on the flocculation box base, and the screw stack dewatering box is arranged on the dewatering box base; a sludge flow rate monitoring sensor is arranged at the sludge inlet, which is used to monitor the real-time sludge flow rate v(t) from the sludge inlet to the sludge outlet of the screw stack dewatering box in real time;

[0056] The flocculation box includes an agitator, a first driving motor is arranged on the upper part of the agitator, an electric control box is arranged on the front part, a water inlet regulating device is arranged on the left side, and a flushing pipe is arranged at the rear; the water inlet regulating device includes a water inlet arranged at the lower part thereof, a flow regulating cylinder arranged vertically at the rear part thereof, an overflow pipe arranged on the flow regulating cylinder, and a water outlet at the lower part thereof;

[0057] The electric control box is provided with a single-chip microcomputer, the single-chip microcomputer is provided with a memory and a processor, the memory is provided with a computer-readable medium storing executable methods, and the computer-readable medium is used by the processor to execute the methods;

[0058] The spiral dehydration box is provided with a spiral shaft running through it in the left and right directions, the radius of the spiral shaft increases continuously from right to left and the pitch between two adjacent spiral blades decreases continuously;

[0059] A plurality of dynamic and static ring combinations are stacked in sequence from left to right between the spiral dewatering boxes and are sleeved on the outer surface of the spiral blades, and each dynamic and static ring combination consists of a static ring and a dynamic ring; a plurality of L-shaped frames are also arranged on the rear side plate of the spiral dewatering box, and the plurality of L-shaped frames are all connected to the same spray pipe, and the spray pipe is arranged on the upper inner side of the spiral dewatering box, and a plurality of spray heads are arranged on the spray pipe; a second drive motor is arranged on the left side plate of the spiral dewatering box, and the output end of the second drive motor is fixedly connected to the spiral shaft, and a mud discharge bucket is arranged at the lower part thereof; the second drive motor The output end of the motor is also provided with a speed monitoring sensor for monitoring the real-time rotation speed of the spiral shaft in real time. The angular velocity sensor and the sludge flow rate monitoring sensor are both communicatively connected to the single-chip microcomputer in the electrical control box; a mud discharge port is also provided on the left side plate of the spiral stack dewatering box, and a back pressure plate is fixedly sleeved on the output end of the second drive motor between the mud discharge port and the second drive motor; a water filter hopper for temporarily receiving and draining filtered water is also provided on the base of the dewatering box, and the water filter hopper is offset upward at an angle of γ relative to the horizontal plane, and a drainage port is provided in the direction close to the flocculation box.

[0060] Furthermore, the agitator is composed of an upper concave sheet and a lower concave sheet with upper and lower openings facing each other and arranged crosswise in the horizontal and vertical directions. The upper concave sheet and the lower concave sheet are both arranged on the same agitator shaft, and the agitator shaft is fixedly connected to the output end of the first drive motor arranged on the upper part of the flocculation box; an upper agitator plate and a lower agitator plate perpendicular to their respective planes are respectively arranged in the concave spaces of the upper concave sheet and the lower concave sheet, the upper agitator plate is arranged on the agitator shaft and located at the lower part of the transverse section of the upper concave sheet, and the lower agitator plate is also arranged on the agitator shaft and located at the upper part of the transverse section of the lower concave sheet;

[0061] Furthermore, there is a first gap between the static ring and the dynamic ring of each dynamic and static ring combination, and a second gap between two adjacent dynamic and static ring combinations, the first gap distance is equal to the second gap distance, and six fixed rings are evenly spaced on the circumferential outer wall of each static ring. The fixed rings of multiple static rings are connected and fixed from left to right through the dynamic and static ring support rods at corresponding positions and are fixed between the left and right walls of the spiral dehydration box.

[0062] The beneficial effects of the present invention are:

[0063] 1. This invention calculates the shear stress, thrust and pressure gradient between the spiral blades, the spiral shaft surface and the sludge in detail to solve the optimal real-time sludge flow rate v best (t) provides comprehensive and accurate data support. As a result, the water filtration volume is effectively increased, the dewatering performance is optimized, and the operating cost and energy consumption are reduced, providing a scientific guarantee for the efficient operation of the screw stack sludge dewatering machine.

[0064] 2. The present invention gradually constructs the thrust of the spiral shaft surface and spiral blade surface on the sludge in the spiral dewatering box in the case of eccentric motion of the dynamic ring of the dynamic and static ring combination, and the lifting force in the direction of the X axis and the Z axis, and then solves the optimal real-time sludge flow rate under the limitation of the lifting force and the sludge output balance equation and the pressure gradient steady-state equation, so as to achieve the reasonable distribution of the shear stress of the spiral shaft and spiral blade for sludge treatment, reduce the destruction of the flocculant, maintain its structural stability, and thus improve the sludge dewatering performance. At the same time, it can also avoid the waste of flocculants, reduce operating costs, reduce unnecessary mechanical losses and energy consumption, and reduce operating costs.

[0065] 3. Analyze and optimize the force uniformity of the spiral shaft surface and the spiral blade in the tangential and axial directions of the spiral blade in the spiral shaft area separated by two adjacent spiral blades, and ensure that the boundary conditions are Sludge flow rate on the spiral blade surface and the boundary conditions are Sludge flow rate on the screw shaft surface At the same time, the real-time pressure gradient of the sludge on the spiral blade surface is analyzed and solved. and the real-time pressure gradient on the screw shaft surface Then, the shear stress between the axial direction of the spiral blade and the sludge pushed by it is further solved. The shear stress on the spiral shaft surface in the axial direction of the spiral blade and the shear stress that drives the sludge flow This ensures that the pressure distribution of the sludge in the spiral dewatering box is uniform when it is pushed by the spiral shaft and spiral blades, avoiding local excessive pressure and effectively preventing floc rupture. Then, combined with the pressure gradient steady-state equation constructed when solving the optimal real-time sludge flow rate for maximum water filtration,

[0066] This ensures the accuracy of the results obtained and avoids the F X During the calculation process, the solution errors are caused by the fact that the boundary conditions are not set or are set vaguely, and the real-time pressure gradients on the surfaces of the spiral blades and spiral shafts are not distinguished and calculated in detail.

[0067] At the same time, the construction of a steady-state pressure gradient distribution not only does not destroy the flocculants, but also ensures uniform force. At the same time, it will not cause deformation or bending of the spiral shaft and spiral blades due to uneven force, thus avoiding equipment wear due to mechanical imbalance and extending the service life of the equipment.

[0068] 4. The present invention realizes intelligent control of equipment based on real-time monitoring data and dynamic optimization algorithm. By analyzing the eccentric motion trajectory of the dynamic ring and the shear stress of the spiral blades in the spiral shaft area, it can reveal the important mechanical behaviors in the sludge dewatering process, significantly improve the dewatering efficiency of the spiral stacked sludge dewatering machine, reduce the moisture content of the sludge after dehydration, and extend the service life of the equipment, providing a guarantee for achieving the economic and environmental benefits of sludge treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0070] Figure 1 A schematic flow chart of a control method for a screw stack type sludge dewatering machine provided by the present invention;

[0071] Figure 2 A side view of the screw stack sludge dewatering machine provided by the present invention;

[0072] Figure 3 This is a force analysis diagram of the XZ plane of the screw stack type sludge dewatering machine provided by the present invention in the body coordinate system;

[0073] Figure 4 It is a schematic diagram of the three-dimensional coordinate system of the spiral shaft where the spiral shaft and the dynamic and static ring combination in the spiral dehydration box of the present invention are located;

[0074] Figure 5 It is a schematic diagram of the dynamic ring, the static ring and the dynamic ring radius in the dynamic and static ring combination of the present invention;

[0075] Figure 6 A cross-sectional view and a side view of the dynamic and static ring combination provided by the present invention;

[0076] Figure 7 It is a schematic diagram of the eccentric motion of the moving ring relative to the stationary ring within the circumference of the eccentric motion trajectory;

[0077] Figure 8 It is a schematic diagram of the entire trajectory of the eccentric motion of the moving ring relative to the stationary ring in one rotation cycle;

[0078] Fig. 9 It is a schematic diagram of the vertical radial change distance of the moving ring in the z-axis direction in the three-dimensional coordinate system of the spiral axis within one rotation cycle;

[0079] Fig.10 It is a schematic diagram of the force analysis on the spiral shaft surface and spiral blade surface in a spiral shaft area;

[0080] Fig.11 It is a schematic diagram of the sludge flow rate on a partial spiral blade surface in a spiral region and in the axial overlap region of the spiral blade and the spiral shaft on the y-axis;

[0081] Fig.12 It is a schematic diagram of the change of real-time pressure p(t) in a spiral axis area at different sludge flow speeds;

[0082] Fig.13 This is a real-time pressure gradient analysis diagram of sludge on the surface of spiral blades and spiral shaft;

[0083] Fig.14 A schematic diagram of stress analysis of a spiral shaft and spiral blades obtained by simulation using the calculation model constructed by steps S31-S35 of the present invention;

[0084] Fig.15 A rear side view of the screw stack sludge dewatering machine provided by the present invention;

[0085] Fig.16 This is a schematic diagram of the internal structure of the flocculation box;

[0086] Fig.17 It is a cross-sectional schematic diagram of the screw stack dehydration box in the xz plane of the three-dimensional coordinate system of the screw axis;

[0087] Fig.18 A side view of another structure of a screw stack sludge dewatering machine with an enlarged screw stack dewatering box space provided by the present invention;

[0088] Fig.19Another structural side view of another type of screw stack sludge dewatering machine with enlarged screw stack dewatering box space provided by the present invention. DETAILED DESCRIPTION

[0089] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0090] The present invention provides a control method for a screw stack type sludge dewatering machine, which is used to control the sludge as a flocculant mixture entering the screw stack dewatering box 2 to enter at an optimal real-time sludge flow rate, thereby avoiding the flocculants from being destroyed during the screw propulsion dewatering process while achieving the maximum water filtration amount, such as Figure 1 As shown, the method provided by the present invention comprises:

[0091] S1: Real-time monitoring of the real-time rotation speed W(t) of the screw shaft 22 and Figure 2 The mud inlet 201 to the mud outlet 20 (as shown in FIG. Figure 3 The real-time sludge flow rate v(t) obtained by monitoring is shown in FIG. 1 ; the real-time rotation speed W(t) obtained by monitoring is in rpm, which is the number of revolutions per minute;

[0092] S2: Construct a calculation formula for the real-time eccentricity distance of the moving ring relative to the initial position at different axial positions, and further calculate the vertical radial change distance of the moving ring;

[0093] S3: Calculate the force on the upper and lower surfaces of the spiral blades 221 and the spiral shaft 22 in the spiral shaft area separated by two adjacent spiral blades 221, and then obtain the X-axis thrust F on the sludge in the body coordinate system X and Z-axis lifting force F on sludge Z ;

[0094] S4: Under the condition that the sludge is subjected to uniform force in different spiral axis areas, the optimal real-time sludge flow rate that maximizes the filtered water volume is solved;

[0095] S5: Under the control of the optimal real-time sludge flow rate, further determine whether the moisture content of the dehydrated sludge at the sludge discharge port 20 is within the threshold range of the moisture content of the dehydrated sludge. If so, maintain the optimal real-time sludge flow rate at this time; otherwise, repeat the above steps to process the sludge with the updated optimal real-time sludge flow rate.

[0096] like Figure 2As shown, the main body coordinate system of the screw stack sludge dewatering machine is a three-dimensional coordinate system composed of the X-axis, Y-axis and Z-axis in the figure, the X-axis is the left and right direction of the screw stack sludge dewatering machine, the Y-axis is the front and back direction of the screw stack sludge dewatering machine, and the Z-axis is the up and down direction of the screw stack sludge dewatering machine. The present invention adjusts the rotation angular velocity of the spiral shaft 22 in real time to make the sludge evenly stressed in the dewatering machine, optimizes the pushing and filtering process of the sludge, and can significantly increase the total dehydration amount. At the same time, by dynamically monitoring and adjusting the moisture content of the sludge after dehydration, it is ensured that the mud cake reaches the expected moisture content standard to avoid the mud cake being too wet or too dry, which affects subsequent treatment.

[0097] The eccentric motion of the moving ring 232 is jointly determined by the axial thrust driven by the rotation of the spiral shaft 22 and the structural design of the equipment (including the arrangement of the stationary ring 231 and the moving ring). As the spiral shaft 22 rotates driven by the second drive motor 26, the thrust of the spiral shaft 22 and the spiral blade 221 pushes the sludge forward. At the same time, due to the radial distance c between the moving ring 232 and the fixed ring 2310 of the stationary ring 231 and the axial force of the spiral, the moving ring 232 will produce eccentric rotational motion. Therefore, it is necessary to clarify the eccentric motion of the moving ring 232 at different y-axis positions in the three-dimensional coordinate system of the spiral shaft and the change in the radius of the spiral shaft 22 as the y position coordinate increases. The eccentric motion of the moving ring 232 will cause local pressure changes in the sludge, which directly affects the compression and dehydration effect of the sludge. Analyzing the motion trajectory and eccentricity amplitude of the moving ring can clarify its mechanism of action on the sludge pressure distribution and compression and dehydration capacity, thereby optimizing the real-time sludge flow rate of the equipment. As another preferred embodiment of the present invention, step S2 constructs a calculation formula for the real-time eccentric distance of the moving ring relative to the initial position at different axial positions, and further calculates the vertical radial change distance of the moving ring, including:

[0098] S21: Calculate the axial distance of the spiral rod along the axial direction of the spiral axis in the spiral axis region where the i-th spiral blade is located in the three-dimensional coordinate system of the spiral axis:

[0099] Wherein, K is the nonlinear pitch variation index, L is the length of the entire spiral shaft 22 in the y-axis direction in the spiral shaft three-dimensional coordinate system, y∈(0,L]; i=1,2,…N; N+1 is the total number of spiral blades on the spiral shaft. Since the first spiral blade does not contact the dynamic ring of the dynamic and static ring combination 23, it will not affect the water filtration volume. The effect of the first spiral blade on the spiral shaft on the sludge is ignored. When i=1, it corresponds to Figure 3 The second spiral blade from right to left on the spiral shaft of the spiral dehydration box; B i Represents the y-axis in the three-dimensional coordinate system of the spiral axis i The center point of the i-th spiral blade at the spiral axis is y i+1The axial distance between the center points of the i+1th spiral blades on the y axis; i ∈[0,L],y i+1 ∈[0,L],y i+1 >y i ; When the sludge treated is municipal sludge, K = 0.8 ~ 1.2; when the sludge treated is industrial sludge, K = 1.2 ~ 1.5; Figure 3 and Figure 4 As shown, the three-dimensional coordinate system of the spiral axis is composed of an x-axis, a y-axis and a z-axis, wherein the y-axis is the axial direction of the axis of the spiral axis which is inclined at an angle of γ to the XY plane (horizontal plane) of the body coordinate system, the x-axis is the width direction of the bottom plane of the spiral stacking dehydration box 2, which is perpendicular to the y-axis, and the xy plane is a plane parallel to the bottom plane of the spiral stacking dehydration box 2, and the z-axis is the vertical direction perpendicular to the xy-axis. Since the xy plane is inclined at an angle of γ relative to the XY plane, the z-axis is inclined at an angle of γ relative to the Z-axis.

[0100] Furthermore, if Figure 3 , Figure 5 , Figure 6 and Fig.17 As shown, Figure 6 (a) is a schematic cross-sectional view of a static and dynamic ring combination 23 in the xz plane of the spiral shaft body coordinate system. As the sludge flows from right to left along the y-axis of the three-dimensional coordinate system of the spiral shaft, as the spiral shaft gets closer to the mud discharge port 20 on the left, its radius becomes larger and the y-axis axial distance between the two spiral blades gradually decreases. At the same time, since there is a certain circumferential outer wall radius difference c between the circumferential outer wall of the fixed ring 2310 of each static ring 231 in the static and dynamic ring combination 23 and the circumferential outer wall of the dynamic ring 232 in the z-axis direction, the spiral blades will be driven to rotate circumferentially during the rotation of the spiral shaft 22. Furthermore, since the spiral blades 221 have a certain inclination angle relative to the x-axis, that is, the lift angle θ of the spiral blades, the dynamic rings 232 at different y-axis axial positions will be driven to perform periodic eccentric motion relative to their initial positions, as shown in FIG. Figure 7 As shown, a dynamic ring 232 generates relative to a static ring 231 A state diagram of the eccentric distance, the initial position of the moving ring 232 is also located at O1, when it is lifted by the spiral blade 221, an eccentric motion relative to the initial position is generated, and the center of the moving ring 232 moves to O2, and the upper right part thereof is in the circumference of the eccentric motion trajectory within a rotation period T of the spiral shaft 22 ( Figure 7 The spiral blade 221 rotates one circle in one rotation period T, thereby driving a certain moving ring 232 to complete the following operation: Figure 8 The eccentric motion trajectory shown ( Figure 8 The locations of multiple red circles in the image);

[0101] Differently, since the moving ring 232 and the static ring 231 of the moving and static ring combination 23 are both sleeved on the spiral blades, the periodic movement of the moving ring 232 is also related to the change in the radius of the spiral shaft 22, which will affect the contact area between the moving ring 232 and the sludge pushed upward from left to right along the y-axis and the pressure on the sludge which is actually a flocculent mixture. It also affects the amount of water filtered through the first gap between the moving ring and the static ring in the y-axis direction in the process of sludge concentration and dehydration produced as the distance between adjacent spiral blades 221 continues to decrease between the moving ring and the static ring sleeved on the spiral shaft 22, i.e., the outer surface of the spiral blade 221 from left to right. Therefore, it is necessary to analyze and calculate the radius of the spiral shaft 22 at different y-axis positions and the periodic y-axis vertical changes of the moving ring 232;

[0102] S22: Calculate the radius r(y) of the spiral axis (22) at the ordinate in the three-dimensional coordinate system of the spiral axis:

[0103] Wherein, D is the radius variation index of the screw axis (22), D=1.15-1.35;

[0104] S23: Construct the mth i The real-time eccentric distance of the moving ring relative to the initial position of the screw axis in the three-dimensional coordinate system The calculation formula is:

[0105] mth i The first dynamic ring is located between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade, m i =1,2,…M i , M i is the total number of dynamic rings between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade, that is, the total number of dynamic rings in the i-th spiral axis region separated by the spiral blades, and the i-th spiral axis region is the axial region between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade;

[0106] A i is the axial distance from the starting end to the ending end of the i-th spiral blade along the axial direction of the spiral shaft (22), The vertical coordinate is in the three-dimensional coordinate system of the spiral axis. The mth i The eccentric motion amplitude of the moving ring is c is the radius difference between the circumferential outer wall of each moving ring 232 and the circumferential outer wall of the fixed ring 2310; r s is the radius of the outer wall of the moving ring; W(t) is the real-time rotation speed of the screw shaft 22 obtained by real-time monitoring in step S1;

[0107] S24: Calculate the mth i The vertical radial distance of the spiral axis of the moving ring along the z-axis in the three-dimensional coordinate system

[0108] in, For m i The eccentric angle of the moving ring relative to the axis of the initial position; Fig. 9 As shown, in order to clarify the vertical radial change distance of the moving ring 232 in the z-axis direction in the three-dimensional coordinate system of the spiral shaft 22 within one rotation period, c is set to be greater than rs to track the dynamic fluctuation state of the moving ring 232 within one period T. The green dotted sinusoidal fluctuation line in the figure is the trajectory of the center of the moving ring during its eccentric motion, and the black sinusoidal fluctuation line is the trajectory of a point on the circumference of the moving ring 232 during the left eccentric motion of the moving ring within one rotation period T. Fig. 9 Known Discovery In -(c+r s ) to (cr s ) range, so when c is actually less than rs, The range of variation is to add a negative sign to all values ​​within the above range of variation. Therefore, at this time, exist Fluctuates within the range.

[0109] The present invention calculates the axial distance Bi between two adjacent spiral blades and the eccentric distance of mi moving rings in the i-th spiral shaft region separated from the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade in one rotation cycle and the vertical radial distance change in the z-axis direction according to the three-dimensional coordinate system of the spiral shaft through step S21. Ensure that the pitch changes at different axial positions are adapted to the sludge characteristics, which is conducive to the subsequent construction of the steady-state compression force distribution and force analysis of the sludge during the axial advancement along the y-axis, that is, it is helpful to analyze the model construction and analysis of the horizontal thrust FX and vertical lifting force FZ of the upper and lower surfaces of the spiral shaft and the blades on the sludge in the body coordinate system, so as to ensure that the sludge in each area of ​​the spiral shaft is uniformly stressed, which is conducive to the subsequent optimization of the compression and water filtration effect of the gap between the dynamic ring and the static ring on the sludge. The equilibrium limit equation and the pressure gradient steady-state equation are constructed to solve the water filtration volume Q within a spiral shaft rotation period T. water Maximum optimal real-time sludge flow rate v best (t). Through the three-dimensional coordinate system analysis of the screw shaft, dynamic control of the screw shaft speed and sludge flow rate, combined with real-time eccentric motion and force calculation, it is helpful to optimize the operating efficiency of the screw stack sludge dewatering machine.

[0110] The shearing effect of the spiral blade surface and the spiral shaft surface on the sludge not only pushes the sludge forward, but also exerts a destructive effect on the sludge flocs. Excessive shear stress may cause the flocs to break, thereby increasing the difficulty of water filtration and reducing the dehydration efficiency. Therefore, in order to improve the compression and filtration efficiency of the sludge and avoid floc destruction caused by excessive shearing, it is necessary to analyze the distribution of shear stress on the spiral shaft surface and the spiral blade surface, which helps to strike a balance between sludge pushing and floc protection. As another preferred embodiment of the present invention, step S3 includes:

[0111] S31: Calculate Fig.10 The mth i The surface of the spiral blade 221 is in the tangential direction of the spiral blade (i.e. Figure 3 , Fig.10 The shear stress between the sludge driven by it and the sludge and mth i The shear stress of the surface of the spiral shaft 22 in the spiral shaft area where the spiral blades 221 are located in the tangential direction of the spiral blades and the shear stress that drives the sludge flow

[0112] v α (t) is the flow velocity of the sludge in the tangential direction of the spiral blade 221, v α (t) = v(t)arcsinθ; Fig.10 for Figure 3 The upper part of the enlarged picture is as follows: Fig.10 In the left part, since the tangential direction of the spiral blade (α direction) is the rise angle of the spiral blade 221, its inclination angle relative to the x-axis of the three-dimensional coordinate system of the spiral axis is θ, and the axial direction of the spiral blade (β direction) is perpendicular to the tangential direction of the spiral blade (α direction), its inclination angle relative to the y-axis of the three-dimensional coordinate system of the spiral axis is θ. The real-time flow rate of the sludge as a flocculant mixture entering the spiral dewatering box 2 along the y-axis is monitored and obtained as v(t). Therefore, the flow rate of the sludge in the tangential direction of the spiral blade 221 is v α (t), through the three-dimensional coordinate system of the spiral axis and the velocity decomposition of the tangential (α direction) and axial (β direction) of the spiral blade, it can be known that v α (t) = v(t)arcsinθ, v β (t) = v(t) arccos; σ is the viscosity coefficient of the sludge entering the screw press dewatering box 2, σ = 0.01 ~ 0.5 Pa·s; when the sludge is a flocculent mixture of municipal sewage after flocculation treatment, 0.01Pa·s≤σ≤0.1Pa·s; when the sludge is a flocculent mixture of industrial sewage after flocculation treatment, 0.1Pa·s<σ≤0.5Pa·s;

[0113] S32: Calculate Fig.10 The mth i The surface of each spiral blade 221 is in the axial direction of the spiral blade (i.e. Figure 3 , Fig.10 The shear stress between the sludge driven by it (in the β direction) and the mth i The shear stress of the surface of the spiral shaft 22 in the spiral shaft area where the spiral blades 221 are located in the axial direction of the spiral blades and the shear stress of the sludge flow.

[0114] S33: According to the calculation results of step S31 and step S32, further calculate the mth i The thrust of the spiral blade 221 surface on the sludge in the X-axis direction in the body coordinate system and Z-axis thrust

[0115]

[0116] Wherein, θ is the helix angle of the helical blade; γ is the inclination angle of the helical axis 22 relative to the horizontal plane of the body coordinate system;

[0117] S34: mth i The thrust of the spiral shaft surface in the spiral shaft area where the spiral blades 221 are located on the sludge in the X-axis direction in the body coordinate system and Z-axis thrust

[0118]

[0119] Furthermore, if Fig.10 From the coordinate system position relationship on the right side, it can be seen that the inclination angle of the y-axis of the three-dimensional coordinate system of the spiral shaft relative to the XY plane of the body coordinate system is γ. Therefore, the inclination angle of the tangential direction (α direction) of the spiral blade relative to the Z axis of the body coordinate system is (θ+γ), and the inclination angle of the axial direction (β direction) of the spiral blade relative to the X axis of the body coordinate system is also (θ+γ); Fig.10 The right part, A i is the axial length of the spiral blade along the y-axis, B i is the length of the spiral axis in the i-th spiral axis region where the corresponding spiral blade is located. Due to the rotation characteristics of the spiral blade, A i and B i There is some overlap in some areas. Fig.10 The force analysis coordinate system on the upper right side is the force analysis of the surface of the screw shaft 22 in the i-th screw shaft area, that is, Conversion analysis between the screw axis three-dimensional coordinate system and the body coordinate system; Fig.10 The force analysis coordinate system on the lower right side is the force analysis of the surface of the spiral blade 221 in the i-th spiral axis area, that is, Through the conversion analysis between the three-dimensional coordinate system of the spiral shaft and the coordinate system of the body, the X-axis and Z-axis force calculation formulas of the spiral shaft surface and the spiral blade surface in the i-th spiral shaft area in step S33 and step S34 can be obtained;

[0120] S35: Based on the calculation results of step S33 and step S34, further calculate the X-axis thrust F of the sludge in the body coordinate system X and Z-axis lifting force F on sludge Z Since the spiral blade rotates 360° (i.e. 2π) in one rotation cycle, and the spiral blade 221 in the i-th spiral axis region just makes the common M in the region in one rotation cycle T i The moving rings rotate in turn through a cycle, so the contact area between the moving ring and the sludge in the vertical direction is exactly therefore, The area occupied by the spiral blade in the X-axis direction of the body coordinate system The thrust of the sludge in the xz section due to the eccentric motion of the spiral blade and the moving ring is X The thrust contribution of the spiral blades is also due to the inclination angle γ of the spiral shaft, which will also generate a certain thrust on the sludge in the X-axis direction of the body coordinate system during the rotation process. Therefore, The contact area between it and the sludge is The area occupied by the spiral axis along the i-th spiral axis The proportional force is the force acting on F X The thrust contribution of the screw shaft is F. X , the model construction analysis of Fz is similar to this, so the calculation formulas for the two are as follows:

[0121]

[0122] Further, step S32 includes the following steps:

[0123] S321: Construct an equation between the pressure gradient of the sludge flow in the y-axis direction of the spiral axis three-dimensional coordinate system and the sludge flow velocity v(t):

[0124]

[0125] Wherein, p(t) is the real-time pressure of the sludge on the surface of the spiral shaft 22 and the spiral blade 221; v β (t) is the flow velocity of sludge in the axial direction of the spiral blade; vβ (t) = v(t)arccosθ;

[0126] like Fig.11 As shown, it is the axial length A of the part of the spiral blade in the ith spiral axis region along the y-axis direction of the spiral axis three-dimensional coordinate system. i And the change of sludge flow velocity in the overlapping part of the spiral blade and the spiral shaft along the y-axis direction, such as Fig.12 As shown in the figure, the change of real-time pressure p(t) in a spiral axis area under different sludge flow speeds; the second-order derivative of the sludge flow speed on the z-axis of the spiral axis three-dimensional coordinate system (in the tangent direction to the spiral axis, i.e. Figure 3 , Fig.10 The z-axis component when interacting with the α direction of the spiral axis, that is, the z-axis viscous velocity of the sludge flow) and the first-order derivative of the sludge flow velocity in the y-axis direction of the spiral axis three-dimensional coordinate system (the y-axis flow velocity when interacting with the axial direction of the spiral axis) have the following relationship:

[0127]

[0128] This equation shows that when the ordinate y of the three-dimensional coordinate system of the spiral axis is fixed, the z-back viscosity velocity generated when it interacts with the tangential direction of the spiral axis is It is the flow velocity in the y-axis direction when the helical axis interacts with the axial direction in the y-axis direction;

[0129] S322: Further solve the equation constructed in step S321 and The first-order derivative of the boundary conditions is obtained, and then the calculation of the mth i The surface of each spiral blade 221 is in the axial direction of the spiral blade (i.e. Figure 3 , Fig.10 The shear stress between the sludge driven by it (in the β direction) and the mth i The shear stress of the spiral shaft surface in the spiral shaft area where the spiral blades 221 are located in the axial direction of the spiral blades and the shear stress of the sludge flow.

[0130] in, is the real-time pressure gradient of the sludge on the surface of the spiral blade (221), is the real-time pressure gradient of the sludge on the surface of the screw shaft 22;

[0131]

[0132] like Fig.13 As shown, Fig.13(a) shows the real-time pressure gradient change of the sludge on the spiral blade surface as the positions of the y-axis and z-axis change continuously. Fig.13 (b) is the real-time pressure gradient change of the sludge on the spiral shaft surface as the positions of the y-axis and z-axis change continuously;

[0133] As the y-axis position in the three-dimensional coordinate system of the spiral axis increases, the contact area between the spiral blade and the sludge on the xz section gradually decreases and the xz section of the spiral axis gradually increases. Therefore, Fig.13 (a) shows the real-time pressure of sludge on the spiral blade surface. Gradually decrease; such as Fig.13 (b) shows the real-time pressure of sludge on the screw shaft surface. gradually increase in size;

[0134] As the z-axis position in the three-dimensional coordinate system of the spiral shaft increases, when the y-axis position is fixed, as the z-axis position coordinate increases, since the spiral blade is fixed at the fixed position of the y-axis, the real-time pressure of the sludge on the entire spiral blade is uniform. Therefore, as the z-axis position increases, the real-time pressure of the sludge on the spiral blade It is similar, but with the continuous increase of the y-axis position, the real-time pressure of the sludge on different spiral blades at different positions is gradually reduced, and the spiral blade at the bottom (that is, the spiral blade closer to the starting end of the right side of the spiral shaft) receives greater pressure; for the spiral shaft surface, when the y-axis position is fixed, that is, the spiral shaft surface at a fixed point on the y-axis, as the position coordinate of the z-axis continues to increase, the spiral shaft surface can bear and contact more sludge, so the real-time pressure of the sludge on it is It increases gradually;

[0135] S323: Then solve and get the mth i The surface of the spiral blade (221) is in the axial direction of the spiral blade (i.e. Figure X The shear stress between the sludge driven by it (in the β direction) and the mth i The surface of the spiral shaft in the spiral shaft region where the spiral blades (221) are located has a shear stress in the axial direction of the spiral blades and a shear stress that drives the sludge to flow.

[0136]

[0137] The present invention firstly performs the following steps S31-S35 on the spiral shaft and the spiral blades in the plurality of spiral shaft regions obtained by separating two adjacent spiral blades at different y-axis positions in the spiral shaft three-dimensional coordinate system: Figure 3 , Fig.10The sludge flow velocity in the tangential and axial directions of the spiral blades: v α (t), v β (t), and then further through the above Fig.13 The real-time pressure gradient of the sludge on the spiral shaft and spiral blade surface is analyzed and calculated, and the shear stress of the spiral blade on the sludge in the tangential and axial directions is further calculated: And the shear stress of the spiral shaft on the sludge in the tangential and axial directions: Then convert it to the shear force in the X-axis and Z-axis directions on the surface of the spiral shaft and the spiral blade in the body coordinate system, and then obtain the X-axis thrust F of the spiral sludge dewatering machine on the sludge in the body coordinate system. X and Z-axis lifting force F on sludge Z ,like Fig.14 As shown, the stress analysis of the spiral shaft 22 and the spiral blade 221 obtained by simulating the calculation model constructed by the steps S31-S35 of the present invention. By calculating the shear stress between the spiral blade and the sludge in the tangential direction and the tangential shear stress between the spiral shaft surface and the sludge The flow resistance of the sludge during the advancement process is clarified, which provides a basis for the subsequent calculation of the thrust in the X-axis direction and the lifting force in the Z-axis direction of the screw dehydrator to overcome the flow resistance; in addition, through the real-time pressure gradient The velocity v between the sludge and the spiral blades and the spiral shaft in the axial direction of the spiral blades β (t), the geometric and mechanical properties of the spiral blades are used to link the flow rate of the sludge with its stress state, providing component force data for the subsequent optimization objective function, clarifying the dynamic characteristics of the sludge at different axial positions, and dynamically adjusting the flow rate to adapt to different sludge characteristics by clarifying the relationship between the sludge flow rate and the force on the spiral blades and the shaft surface, thereby maximizing the dewatering efficiency. The analysis of pressure gradient and shear stress helps to avoid excessive shear force from destroying sludge flocs when optimizing the flow rate, and ensure the quality of solid-liquid separation.

[0138] As another preferred embodiment of the present invention, step S4 includes:

[0139] S41: Calculate the total amount of sludge Q that is processed by the screw shaft 22 within one rotation period T of the screw shaft 22 total , the amount of filtered water Q generated by the sludge treatment in the spiral dewatering box (2) water :

[0140]

[0141] Wherein, s is the first gap distance between the moving ring 232 and the stationary ring 231 of each moving and stationary ring combination 23, s=0.2mm-1.0mm; t represents the time t; t∈[t0,t0+T], t0 is the starting time of a rotation cycle;

[0142] S42: Construct the limiting equation for the balance between lifting force and sludge discharge within the cycle to solve the optimal real-time sludge flow rate:

[0143] Q total -Q water =η(F z -Q waterρout ) / ρ, where ρ is the sludge density, η is the screw shaft transmission efficiency coefficient, η = 0.7 ~ 0.9; ρ out is the density of the escaped water, ρ out =1.00~1.10g / cm 3 ;

[0144] And construct the pressure gradient steady-state equation to solve the optimal real-time sludge flow rate:

[0145] in, is the gradient calculation symbol; ρ is the density of the sludge (i.e., flocculant mixture) generated by the reaction of the sewage entering the flocculation tank 1 with the flocculant, ρ = 1.01 ~ 1.10 g / cm 3 ; When the sludge treated is municipal sludge, ρ = 1.01 ~ 1.04g / cm 3 When the treated sludge is industrial sludge, ρ = 1.04 ~ 1.10 g / cm 3 ;

[0146] S43: Under the constraints of the equilibrium constraint equation and the pressure gradient steady-state equation constructed in step S42, solve the water filtering amount Q within one spiral axis rotation period T water Maximum optimal real-time sludge flow rate v best (t):

[0147]

[0148] In step S5, after one cycle of sludge dehydration at the optimal real-time sludge flow rate, the moisture content of the dehydrated sludge at the sludge outlet is W final The calculation formula is as follows:

[0149]

[0150] Wherein, W0 is the initial moisture content of the sludge after being mixed with the flocculant at the sludge inlet 202 entering the screw press dewatering box 2, W0=90% to 95%.

[0151] The threshold range of moisture content of sludge after dehydration is 60% to 80%. final ≤80%, then continue to process the sludge at this real-time sludge flow rate, otherwise repeat steps S1-S4 to solve the latest optimal real-time sludge flow rate so that the moisture content of the dehydrated sludge at the outlet is W final Within the threshold range of 60% to 80%.

[0152] The present invention also provides a screw stack type sludge dewatering machine using the above method, the method is used to control the real-time dynamic operation of the screw stack type sludge dewatering machine, such as Figure 2 , Figure 3 , Fig.15 As shown, the dewatering machine includes a flocculation box 1, a spiral dewatering box 2, and a mud inlet 201 of the spiral dewatering box 2 is connected to a mud outlet 101 of the flocculation box 1 through a mud inlet pipe 3; the flocculation box 1 is fixedly arranged on a flocculation box base 11, and the spiral dewatering box 2 is arranged on a dewatering box base 21; a mud flow rate monitoring sensor is arranged at the mud inlet 201, which is used to monitor the real-time mud flow rate v(t) from the mud inlet 201 to the mud outlet 20 of the spiral dewatering box 2 in real time;

[0153] The flocculation box 1 includes an agitator 12, a first driving motor 13 is arranged on the upper part of the agitator 12, an electric control box 14 is arranged at the front part, a water inlet regulating device 15 is arranged at the left side, and a flushing pipe 16 is arranged at the rear part; Figure 2 and Fig.15 In order to clearly define the positional relationship between the mud inlet 202 and the mud outlet 101, the mud inflow pipe 3 is omitted in the figure.

[0154] like Fig.16 As shown, the water inlet regulating device 15 comprises a water inlet 151 arranged at the lower part thereof, a flow regulating cylinder 152 arranged vertically at the rear part thereof, an overflow pipe 153 arranged on the flow regulating cylinder 152 and a water outlet 154 at the lower part thereof; the sewage is pumped into the water inlet 151 and gradually fills the water inlet regulating device 15 from bottom to top, and a part of it enters the flocculation box 1 through the connecting port 151 on the left side wall 111 of the flocculation box 1 and the water inlet regulating device 15, and after being mixed with the flocculant, it further enters the stacking screw dewatering device through the mud outlet 101, the mud inflow pipe 3 and the mud inlet 201 in sequence. In the water tank 2; when the water entering from the water inlet 151 completely fills the water inlet regulating device 15, the excess water flows from the overflow pipe from top to bottom into the flow regulating device 152, and is finally discharged through the water outlet 154 at the bottom of the water inlet regulating device 15, to prevent the water from overflowing from the upper part of the water inlet regulating device 15 or the upper surface of the flocculation box 1; the lower part of the flocculation box 1 is also provided with a sewage outlet 112, which is used to regularly clean the flocculation box 1 to discharge the dirty water inside or regularly open the sewage outlet 112 to discharge the residual mixture therein, so as to wait for the whole dehydrator to be reopened for a new sewage treatment process;

[0155] The electric control box 14 is provided with a single chip microcomputer, the single chip microcomputer is provided with a memory and a processor, the memory is provided with a computer readable medium storing executable methods, and the computer readable medium is used by the processor to execute the above method;

[0156] A spiral shaft 22 is provided in the spiral dewatering box 2, which runs through it in the left and right directions. The radius of the spiral shaft 22 increases continuously from right to left (i.e., from the water inlet direction to the water outlet direction, which is also the y-axis direction of the three-dimensional coordinate system of the spiral shaft), and the pitch between two adjacent spiral blades 221 decreases continuously; the sludge moves forward continuously with the rotation of the spiral shaft; along the mud cake outlet direction, the distance between two adjacent spiral blades of the spiral shaft gradually decreases, the radius of the spiral shaft increases continuously, and the volume of the spiral cavity shrinks continuously. Under the continuous operation of the spiral driving shaft, the moisture in the sludge is squeezed out, the solid content of the filter cake increases continuously, and finally the continuous dehydration of the sludge is achieved.

[0157] Multiple dynamic and static ring combinations 23 (such as Figure 6(b) are stacked from left to right and sleeved on the outer surface of the spiral blade 221, and each dynamic and static ring combination 23 is composed of a static ring 231 and a dynamic ring 232; a plurality of L-shaped frames 24 are also arranged on the rear side plate of the spiral stacking and dehydrating box 2, and the plurality of L-shaped frames 24 are all connected to the same spray pipe 25, the spray pipe is arranged on the upper side of the interior of the spiral stacking and dehydrating box 2, and a plurality of spray heads 251 are arranged on the spray pipe 25, and each spray head 251 is arranged between two adjacent L-shaped frames 24; a plurality of L-shaped frames 24 are arranged on the left side plate of the spiral stacking and dehydrating box 2 A second drive motor 26 is provided, the output end of the second drive motor 26 is fixedly connected to the screw shaft 22, and a mud discharge hopper 27 is provided at the lower part thereof, which is used to discharge the dehydrated sludge to the sludge storage device; a speed monitoring sensor for real-time monitoring of the real-time rotation speed of the screw shaft 22 is also provided at the output end of the second drive motor 26, and the angular velocity sensor and the sludge flow rate monitoring sensor are both connected to the single-chip microcomputer in the electric control box 14 for communication; a mud discharge port 20 is also provided on the left side plate of the spiral stack dewatering box 2, and the mud discharge port 20 is connected to the second drive motor 2 6, a back pressure plate 29 is also fixedly sleeved on the output end of the second drive motor 26; the back pressure plate 29 is fixedly connected to an electric telescopic rod 291 on one side of the left side plate of the installation box 261 close to the second drive motor 26, and the telescopic end of the electric telescopic rod 291 is fixedly connected to the back pressure plate 29, and a spring 292 is sleeved on the output end of the second drive motor 26 between the inner side plate on the left side of the installation box 261 and the back pressure plate; by intermittently controlling the extension and retraction of the electric telescopic rod, the back pressure plate 29 is intermittently tightly connected to the mud discharge port 20. The dehydrated sludge pushed out by the spiral shaft 22 and the spiral blade 221 at the mud discharge port 20 is squeezed again to form a mud cake, and then slides down from the mud discharge bucket 27 and enters the mud cake collecting device provided at the lower part of the mud discharge bucket 27; the function of the spring 292 is that when the electric telescopic rod 291 is extended, the spring 292 is stretched from the initial state to generate a retraction force, thereby assisting the retraction of the electric telescopic rod 291. Driven by the retraction force of the electric telescopic rod 291 and the retraction force of the spring 292, the back pressure plate 29 returns to the initial position;

[0158] The dehydration tank base 21 is also provided with a filter hopper 211 for temporarily receiving and draining the filtered water. The filter hopper 211 is offset upwards by an angle γ relative to the horizontal plane, and a drain port 212 is provided in the direction close to the flocculation tank 1.

[0159] like Figure 2 , Figure 4 , Fig.17As shown, a plurality of hollow fixed plates 28 are sequentially arranged from right to left in the spiral dehydration box 2. Two adjacent fixed plates 28 are fixedly connected by fixed rods 281 arranged axially at equal intervals. The hollow middle portion of the fixed plate 28 allows the spiral shaft 22 and the spiral blade 221 to pass through it, thereby ensuring that the plurality of dynamic and static ring assemblies 23 can ensure that the spiral blade 221 rotates when the spiral shaft 22 drives the spiral shaft 221. Figure 8 The eccentric motion trajectory shown moves up and down periodically, thereby completing the dewatering of the sludge as a flocculent mixture.

[0160] The first drive motor 13 is used to drive the agitator 12 to rotate in situ. After the flocculant is added into the flocculation box 1, the mixture of muddy water and the flocculant entering the connecting port 151 is continuously stirred to facilitate the flocculation reaction between the flocculant and the sewage entering the flocculation box 1 from the water inlet 151. The flocculant used is usually polyacrylamide (PAM). The polyacrylamide reacts with the surface of the sludge particles in the sewage to reduce the electrostatic repulsion on the surface of the sludge particles. Then, through the characteristics of the longer molecular chain of PAM itself, the sludge particles that have reduced the electrostatic repulsion and adsorbed each other are connected together to produce a large number of floccules, thereby flocculating and precipitating the sludge in the incoming sewage.

[0161] like Fig.16 As shown, the stirrer 12 is composed of an upper concave sheet 121 and a lower concave sheet 122 with upper and lower openings facing each other and arranged crosswise in the horizontal and vertical directions. The upper concave sheet 121 and the lower concave sheet 122 are both arranged on the same stirring shaft 123, and the stirring shaft 123 is fixedly connected to the output end of the first driving motor 13 arranged on the upper part of the flocculation box 1; an upper stirring plate 124 and a lower stirring plate 125 perpendicular to the planes where they are located are respectively arranged in the concave spaces of the upper concave sheet 121 and the lower concave sheet 122, and the upper stirring plate 124 is arranged on the stirring shaft 123. The lower stirring plate 125 is also arranged on the stirring shaft 123 and located at the upper part of the transverse section of the lower concave plate 122; therefore, the lower concave plate 122 and the upper stirring plate 124 are in the XZ plane of the body coordinate system in the initial state, and the upper concave plate 121 and the lower stirring plate 125 are in the YZ plane of the body coordinate system in the initial state. Through this structural design, the flocculant can be fully reacted with the sewage entering the flocculation box through continuous stirring.

[0162] There is a first gap between the static ring 231 and the dynamic ring 232 of each static-dynamic ring combination 23, and a second gap between two adjacent static-dynamic ring combinations 23. The first gap distance is equal to the second gap distance (the first gap distance and the second gap distance are both axial distances along the y-axis direction of the three-dimensional coordinate system of the spiral axis). Six fixed rings 2310 are also evenly spaced on the circumferential outer wall of each static ring 231. The fixed rings 2310 of multiple static rings 231 are connected and fixed from left to right through the static-dynamic ring support rods 233 at corresponding positions and are fixed between the left and right walls of the spiral dehydration box.

[0163] According to the amount of sludge to be dehydrated, the size of the spiral dewatering box 2 in the spiral dewatering machine can be adjusted, and multiple spiral shafts 22 are arranged in parallel in the Y-axis direction of the main body coordinate system, and then correspondingly, there are multiple mud inlets 201 at the right end of the spiral dewatering box 2, and the spiral dewatering box 2 has multiple spray pipes 25 arranged in parallel along the y-axis of the three-dimensional coordinate system of the spiral shaft. Multiple second drive motors 26 are arranged on the left side wall of the spiral dewatering box 2, and multiple mud outlets are arranged on the left side of the flocculation box 1. 101, each mud outlet 101 is connected to the mud inlet 201 through a mud inlet pipe 3, and then the sludge after flocculation treatment in the flocculation box 1 enters the spiral stacking dehydration area where the three spiral shafts are located through the mud inlet pipe 3 in turn, and the mud inlet 201, the mud outlet 101, the sewage inlet pipe 3, the spray pipe 25, and the second drive motor 26 are the same in number as the spiral shaft 22 and are arranged one by one to cooperate to complete the spiral stacking dehydration and the subsequent sludge on the y-axis axial gap of the dynamic and static rings arranged on the outer surface of the spiral shaft 22; Fig.18 , Fig.19 As shown, the number of the mud inlet 201 , the mud outlet 101 , the spray pipe 25 , the second drive motor 26 and the screw shaft 22 is set to three.

[0164] The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a screw stack sludge dewatering machine, the method being used to control the sludge as a flocculant mixture entering a screw stack dewatering box (2) to enter at an optimal real-time sludge flow rate, thereby avoiding the flocculants from being destroyed during the screw propulsion dewatering process while achieving a maximum water filtration rate, characterized in that: The method comprises: S1: real-time monitoring of the real-time rotation speed W(t) of the screw shaft (22) and the real-time sludge flow rate v(t) from the sludge inlet (201) to the sludge outlet (20) of the screw stack dewatering box (2); S2: Construct a calculation formula for the real-time eccentric distance of the moving ring relative to the initial position at the axial position of the y-axis of the three-dimensional coordinate system of different spiral axes, and further calculate the vertical radial change distance of the moving ring; S3: Calculate the force on the upper and lower surfaces of the spiral blade (221) and the spiral shaft (22) in the spiral shaft area separated by two adjacent spiral blades (221), and then obtain the X-axis thrust F on the sludge in the body coordinate system. X and Z-axis lifting force F on sludge Z ; S4: Under the condition that the sludge is subjected to uniform force in different spiral axis areas, the optimal real-time sludge flow rate that maximizes the filtered water volume is solved; S5: Under the control of the optimal real-time sludge flow rate, further determine whether the moisture content of the dehydrated sludge at the sludge discharge port (20) is within the threshold range of the moisture content of the dehydrated sludge. If so, maintain the optimal real-time sludge flow rate at this time; otherwise, repeat the above steps to process the sludge at the updated optimal real-time sludge flow rate.

2. The control method of the screw stack sludge dewatering machine according to claim 1, characterized in that: The S2 step includes: S21: Calculate the axial distance of the spiral rod along the axial direction of the spiral axis in the spiral axis region where the i-th spiral blade is located in the three-dimensional coordinate system of the spiral axis: Wherein, K is the nonlinear pitch variation index, L is the length of the entire spiral axis (22) along the y-axis in the spiral axis three-dimensional coordinate system, y∈(0,L]; i=1,2,…N; N+1 is the total number of spiral blades on the spiral axis; B i Represents the y-axis in the three-dimensional coordinate system of the spiral axis i The center point of the i-th spiral blade at the spiral axis is y i+1 The y-axis axial distance between the center points of the i+1th spiral blade; i ∈[0,L],y i+1 ∈[0,L],y i+1 >y i ; When the sludge treated is municipal sludge, K = 0.8 ~ 1.2; when the sludge treated is industrial sludge, K = 1.2 ~ 1.5; S22: Calculate the radius r(y) of the spiral axis (22) at the ordinate in the three-dimensional coordinate system of the spiral axis: Wherein, D is the radius variation index of the screw axis (22), D=1.15-1.35; S23: Construct the mth i The real-time eccentric distance of the moving ring relative to the initial position of the screw axis in the three-dimensional coordinate system The calculation formula is: mth i The first dynamic ring is located between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade, m i =1,2,…M i , M i is the total number of dynamic rings between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade, that is, the total number of dynamic rings in the i-th spiral axis region separated by the spiral blades, and the i-th spiral axis region is the axial region between the starting end of the i-th spiral blade and the starting end of the i+1-th spiral blade; A i is the axial distance from the starting end to the ending end of the i-th spiral blade along the axial direction of the spiral shaft (22), The vertical coordinate is in the three-dimensional coordinate system of the spiral axis. The mth i The eccentric motion amplitude of the moving ring is c is the radius difference between the circumferential outer wall of each moving ring (232) and the circumferential outer wall of the fixed ring (2310); r s is the radius of the outer wall of the moving ring; W(T) is the real-time rotation speed of the screw shaft (22) obtained by real-time monitoring in step S1; S24: Calculate the mth i The vertical radial distance of the spiral axis of the moving ring along the z-axis in the three-dimensional coordinate system in, For m i The eccentricity angle of the moving ring relative to the axis of the initial position; 3. The control method of the screw stack sludge dewatering machine according to claim 2, characterized in that: The S3 step includes: S31: Calculate the mth i The shear stress between the surface of the spiral blade (221) in the tangential direction of the spiral blade and the sludge pushed by the spiral blade and mth i The surface of the spiral shaft (22) in the spiral shaft region where the spiral blades (221) are located has a shear stress in the tangential direction of the spiral blades and a shear stress that drives the sludge to flow. v α (t) is the flow velocity of the sludge in the tangential direction of the spiral blade (221), v α (t) = v (t) arcsinθ; σ is the viscosity coefficient of the sludge entering the screw dewatering box (2), σ = 0.01 ~ 0.5 Pa·s; S32: Calculate the mth i The shear stress between the surface of the spiral blade (221) in the axial direction of the spiral blade and the sludge driven by the spiral blade mth i The surface of the spiral shaft (22) in the spiral shaft region where the spiral blades (221) are located has a shear stress in the axial direction of the spiral blades and a shear stress that drives the sludge to flow. S33: According to the calculation results of step S31 and step S32, further calculate the mth i The surface of the spiral blade (221) exerts a thrust in the X-axis direction on the sludge in the body coordinate system and Z-axis thrust Wherein, θ is the helical pitch angle of the helical blade; γ is the inclination angle of the helical axis (22) relative to the horizontal plane of the body coordinate system; S34: mth i The thrust of the spiral shaft surface in the spiral shaft region where the spiral blades (221) are located on the sludge in the X-axis direction in the body coordinate system and Z-axis thrust S35: According to the calculation results of step S33 and step S34, further calculate the X-axis thrust F of the sludge in the body coordinate system X and Z-axis lifting force F on sludge Z :

4. The control method of the screw stack sludge dewatering machine according to claim 3, characterized in that: The step S32 includes the following steps: S321: Construct an equation between the pressure gradient of the sludge flow in the y-axis direction of the spiral axis three-dimensional coordinate system and the sludge flow velocity v(t): Wherein, p(t) is the real-time pressure of the sludge on the surface of the spiral shaft (22) and the spiral blade (221); v β (t) is the flow velocity of the sludge in the axial direction of the spiral blade (221), v β (t) = v(t)arccosθ; S322: Further solve the equation constructed in step S321 and The first-order derivative of the boundary conditions is obtained, and then the calculation of the mth i The shear stress between the surface of the spiral blade (221) in the axial direction of the spiral blade and the sludge driven by the spiral blade mth i The surface of the spiral shaft in the spiral shaft region where the spiral blades (221) are located has a shear stress in the axial direction of the spiral blades and a shear stress that drives the sludge to flow. in, is the real-time pressure gradient of the sludge on the surface of the spiral blade (221), is the real-time pressure gradient of the sludge on the surface of the spiral shaft (22); S323: Then solve and get the mth i The shear stress between the surface of the spiral blade (221) in the axial direction of the spiral blade and the sludge driven by the spiral blade mth i The surface of the spiral shaft in the spiral shaft region where the spiral blades (221) are located has a shear stress in the axial direction of the spiral blades and a shear stress that drives the sludge to flow.

5. The control method of the screw stack sludge dewatering machine according to claim 3, characterized in that: The S4 step includes: S41: Calculate the total amount of sludge Q that is processed by the screw shaft (22) during one rotation period T of the screw shaft (22) total , the amount of filtered water Q generated by the sludge treatment in the spiral dewatering box (2) water : Wherein, s is the first gap distance between the moving ring (232) and the stationary ring (231) of each moving and stationary ring combination (23), s=0.2mm-1.0mm; t represents the time t; t∈[t0,t0+T], t0 is the starting time of a rotation cycle; S42: Construct the limiting equation for the balance between lifting force and sludge discharge within the cycle to solve the optimal real-time sludge flow rate: Q total -Q water =η(F z -Q water ρ out ) / ρ, where ρ is the sludge density, η is the screw shaft transmission efficiency coefficient, η = 0.7 ~ 0.9; ρ out is the density of the escaped water, ρ out =1.00~1.10g / cm 3 ; And construct the pressure gradient steady-state equation to solve the optimal real-time sludge flow rate: in, is the symbol for gradient calculation; ρ is the density of the sludge produced by the reaction of the sewage entering the flocculation box (1) with the flocculant, ρ = 1.01 ~ 1.10 g / cm 3 ; S43: Under the constraints of the equilibrium limiting equation and the pressure gradient steady-state equation constructed in step S42, solve the water filtering amount Q within one spiral shaft rotation cycle water Maximum optimal real-time sludge flow rate v best (t):

6. The control method of the screw stack sludge dewatering machine according to claim 1, characterized in that: In the step S5, after one cycle of sludge dehydration at the optimal real-time sludge flow rate, the moisture content of the dehydrated sludge at the sludge outlet is W final The calculation formula is as follows: Wherein, W0 is the initial moisture content of the sludge after being mixed with the flocculant at the sludge inlet (202) of the spiral dewatering box (2), W0=90% to 95%.

7. The control method of the screw stack sludge dewatering machine according to claim 1, characterized in that: The threshold range of the moisture content of the sludge after dehydration is 60% to 80%.

8. A screw stack sludge dewatering machine using the method according to any one of claims 1 to 7, the dewatering machine comprising a flocculation box (1), a screw stack dewatering box (2), a sludge inlet (201) of the screw stack dewatering box (2) being connected to a sludge outlet (101) of the flocculation box (1) through a sludge inflow pipe (3); the flocculation box (1) is fixedly arranged on a flocculation box base (11), and the screw stack dewatering box (2) is arranged on a dewatering box base (21); a sludge flow rate monitoring sensor is arranged at the sludge inlet (201) for real-time monitoring of the real-time sludge flow rate v(t) from the sludge inlet (201) to the sludge outlet (20) of the screw stack dewatering box (2); The flocculation box (1) includes an agitator (12), a first driving motor (13) is arranged on the upper part of the agitator (12), an electric control box (14) is arranged on the front part, a water inlet regulating device (15) is arranged on the left side, and a flushing pipe (16) is arranged on the rear part; the water inlet regulating device (15) includes a water inlet (151) arranged at the lower part thereof, a flow regulating cylinder (152) arranged vertically at the rear part thereof, an overflow pipe (153) arranged on the flow regulating cylinder (152), and a water outlet (154) at the lower part thereof; The electric control box (14) is provided with a single-chip microcomputer, the single-chip microcomputer is provided with a memory and a processor, the memory is provided with a computer-readable medium storing a method executable according to any one of claims 1 to 7, and the computer-readable medium is used by the processor to execute the method according to any one of claims 1 to 7; The spiral dehydration box (2) is provided with a spiral shaft (22) penetrating the spiral shaft in the left and right directions, the radius of the spiral shaft (22) continuously increases from right to left and the pitch between two adjacent spiral blades (221) continuously decreases; A plurality of dynamic and static ring assemblies (23) are stacked in sequence from left to right between the spiral dewatering boxes (2) and sleeved on the outer surface of the spiral blades (221), and each dynamic and static ring assembly (23) is composed of a static ring (231) and a dynamic ring (232); a plurality of L-shaped frames (24) are also arranged on the rear side plate of the spiral dewatering box (2), and the plurality of L-shaped frames (24) are all connected to the same spray pipe (25), and the spray pipe is arranged on the upper side of the interior of the spiral dewatering box (2), and a plurality of spray heads (251) are arranged on the spray pipe (25); a second drive motor (26) is arranged on the left side plate of the spiral dewatering box (2), and the output end of the second drive motor (26) is fixedly connected to the spiral shaft (22), and a mud discharge bucket (27) is arranged at the lower part thereof. ; The output end of the second drive motor (26) is also provided with a speed monitoring sensor for real-time monitoring of the real-time rotation speed of the spiral shaft (22); the angular velocity sensor and the sludge flow rate monitoring sensor are both communicatively connected to the single-chip microcomputer in the electric control box (14); a mud discharge port (20) is also provided on the left side plate of the spiral stack dewatering box (2); a back pressure plate (29) is also fixedly sleeved on the output end of the second drive motor (26) between the mud discharge port (20) and the second drive motor (26); a water filter hopper (211) for temporarily receiving and draining filtered water is also provided on the dewatering box base (21); the water filter hopper (211) is offset upward at an angle of γ relative to the horizontal plane, and a water discharge port (212) is provided in the direction close to the flocculation box (1).

9. The screw stack sludge dewatering machine according to claim 8, characterized in that: The stirrer (12) is composed of an upper concave sheet (121) and a lower concave sheet (122) with upper and lower openings facing each other and arranged crosswise in the horizontal and vertical directions. The upper concave sheet (121) and the lower concave sheet (122) are both arranged on the same stirring shaft (123). The stirring shaft (123) is fixedly connected to the output end of a first driving motor (13) arranged on the upper part of the flocculation box (1). An upper stirring plate (124) and a lower stirring plate (125) perpendicular to the planes where the upper and lower concave sheets (121) and the lower concave sheets (122) are respectively arranged in the recessed spaces of the upper concave sheet (121) and the lower concave sheet (122). The upper stirring plate (124) is arranged on the stirring shaft (123) and located at the lower part of the transverse section of the upper concave sheet (121). The lower stirring plate (125) is also arranged on the stirring shaft (123) and located at the upper part of the transverse section of the lower concave sheet (122).

10. The screw stack sludge dewatering machine according to claim 8, characterized in that: A first gap is provided between the static ring (231) and the dynamic ring (232) of each static and dynamic ring combination (23), and a second gap is provided between two adjacent static and dynamic ring combinations (23), wherein the first gap distance is equal to the second gap distance, and six fixed rings (2310) are evenly spaced on the circumferential outer wall of each static ring (231), and the fixed rings (2310) of the plurality of static rings (231) are connected and fixed between the left and right walls of the spiral stacking and dehydrating box through dynamic and static ring support rods (233) at corresponding positions from left to right.

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