CN100593693C - Constant current detection system for rate of flow of sewage - Google Patents

Abstract

A detection system capable of maintaining a constant flow of sewage in large-diameter pipelines and measuring with high precision and on-line detection of other sewage flow measuring instruments. It is connected by a stop valve with a stepping motor and the inlet of the casing, and is connected in sequence by an energy conversion chute, a long axis of force transmission, a square balance damper, a horizontal displacement transmission bracket, a displacement sensor (LVDT), and a main controller. And fixed in the casing, the main controller is connected with the remote computer through the data line. The horizontal momentum generated by the sewage falling freely from the inlet of the casing through the stop valve into the energy conversion chute is transmitted to the square balance damper through the long axis of force transmission, and then transmitted to the displacement sensor through the transmission bracket to generate a current change value, which is determined by the main body. The controller converts A/D at fixed time intervals and converts it into real-time flow. The measured real-time flow is accumulated to obtain the total amount of sewage and the result is displayed by a remote computer. The remote computer can control the system and automatically calibrate it.

Description

Sewage flow constant flow detection system

technical field

The invention relates to a constant flow detection device for sewage flow and a testing device for sewage flow measuring instruments, especially a device capable of detecting sewage flow mixed with various complex components with high precision (with an error not exceeding ±0.1%) and online testing of sewage flow measuring instruments Sewage flow constant flow detection system.

Background technique

As the environmental protection industry has higher and higher requirements for the accuracy and reliability of sewage flow measurement and control, there are more than a dozen types and hundreds of flow meters developed at home and abroad, and the more representative one is the volumetric type. , differential pressure, vortex street, area, electromagnetic, ultrasonic and thermal flowmeters, etc., but because flow is a dynamic quantity, there is not only viscous friction inside the moving liquid, but also different For complex flow phenomena such as stable vortex and secondary flow, the measuring instrument itself is affected by many factors, such as: pipeline, caliber size, shape (circle, rectangle), boundary conditions, physical properties of the medium (temperature, pressure, density, viscosity, dirt, etc.) pollution, corrosiveness, etc.), fluid flow state (turbulence state, velocity distribution, etc.) The factors that affect the detection accuracy are integrated into the special medium. In the actual application of monitoring its flow, the existing flowmeters have the problem of large deviation between the measured flow display value and the actual flow, and in sewage enterprises and sewage treatment The measurement and testing department does not have a convincing standard online inspection device to authoritatively inspect the existing flow meters when there are conflicts caused by inaccurate measurements.

Contents of the invention

In order to overcome the problem that the existing flow meter has too much error in the detection of sewage flow when facing sewage with large flow changes, complex internal conditions, impurities, and corrosive special media, and solve the problem that the metering department does not have an effective online detection flow In view of the difficulty of standard devices for instrument accuracy, the present invention provides a constant flow detection system for sewage flow. The detection flow of the constant flow detection system for sewage flow is not affected by the internal conditions of the fluid, flow changes, impurity components and viscosity.

The technical solution adopted by the present invention to solve the technical problem is: the stepping motor, the reduction box, and the shut-off valve are sequentially connected, and the shut-off valve is fixed outside the casing as an inlet, and the energy conversion chute, the long axis of force transmission, and the square balance The damper, the horizontal displacement transfer bracket, the displacement sensor (LVDT), and the main controller are connected in sequence and fixed in the casing, the displacement sensor (LVDT) is electrically connected to the main controller, and the main controller is connected to a remote computer through a data line. After the sewage enters the casing through the shut-off valve, it freely falls to the energy conversion chute to generate horizontal momentum, which is transmitted to the square balance damper through the long axis of force transmission, and then transmitted to the displacement sensor through the transmission bracket to generate a current change value, which is determined by the main force. The controller converts A/D at fixed time intervals and converts it into real-time flow. The measured real-time flow is accumulated to obtain the total amount of sewage and the result is displayed by a remote computer connected to the main controller. The remote computer can control the sewage flow constant flow detection system And automatic calibration.

The beneficial effects of the present invention are:

1. When the real-time flow is inconsistent with the set target value, the main controller controls the stepper motor to adjust the opening of the stop valve so that the real-time flow is always basically consistent with the set target value, so as to ensure that the flow of sewage flowing through the energy conversion chute is consistent. It is stable near the set target value, eliminating the inaccurate measurement caused by the large change of sewage flow.

2. The sewage flow rate is generated by the sewage impacting the energy conversion chute from the shut-off valve to the energy conversion chute to generate displacement. The horizontal displacement sensor (LVDT) is measured in the form of current change, and then the main controller passes through A/D converted and calculated. No matter how complicated the internal situation of the sewage is, how changeable the impurity composition is, and what the viscosity is, when the sewage passes through the energy conversion chute, the result is only a different horizontal displacement of the energy conversion chute. The high-precision horizontal displacement sensor (LVDT) can The horizontal displacement is dynamically and continuously detected, and the main controller can continuously convert the detection results of the horizontal displacement sensor (LVDT) into instantaneous flow rate after A/D conversion at a fixed speed of more than five times per second, and finally Get accurate sewage volume;

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is the general structural diagram of the present invention.

Spring plate pressing plate (8) among Fig. 1, spring plate splint (9), front balance frame (13), spring plate (14), rear balance frame (15) forms horizontal square balance damper;

Sensor holder (10) among Fig. 1, displacement sensor LVDT (11), transmission bracket (12) form flow detection mechanism;

Among Fig. 1, energy conversion chute (4), power transmission major axis (5), front balance frame (13), spring plate (14), rear balance frame (15), middle wallboard (16) form energy conversion mechanism;

In Fig. 1, stepping motor (1), reduction box (2), stop valve (3), and main controller (7) form a flow control mechanism:

Fig. 2 is an enlarged detailed view of the horizontal square balance damper in Fig. 1 .

Fig. 3 is an enlarged detailed view of the flow detection mechanism in Fig. 1 .

Fig. 4 is main controller (7) internal composition and the overall connection block diagram of computer control of the present invention among Fig. 1.

In the figure 1. Stepping motor, 2. Reducer, 3. Stop valve, 4. Energy conversion chute, 5. Force transmission long shaft, 6. Housing, 7. Main controller, 8. Spring plate pressing plate, 9. Spring plate splint, 10. Sensor fixing seat, 11. Displacement sensor LVDT, 12. Transmission bracket, 13. Front balance frame, 14. Spring plate, 15. Rear balance frame, 16. Middle wall plate, 17. Hand wheel, 18 . Main control board, 19. Stepper motor controller, 20. Analog converter, 21. Remote control computer.

Detailed ways

Energy conversion mechanism: in Fig. 1, energy conversion chute (4), force transmission long axis (5), front balance frame (13), spring plate (14), rear balance frame (15), middle wall plate (16) Tighten the connections sequentially. The horizontal momentum generated by the sewage entering the energy conversion chute (4) in the casing (6) from the shut-off valve (3) is transmitted to the front balance frame of the square balance damper (Fig. 2) through the long axis of force transmission (5) (13). Because the energy conversion chute (4) is not in direct contact with the middle wallboard (16) of the casing, it is only fixed on the long axis of power transmission (5), and the other end of the long axis of power transmission (5) passes through the middle wall of the casing The hole (not in contact with the hole) on the plate (16) is firmly connected with the central inner hole of the front balance frame (13) of the square balance damper (Fig. 2) fixed in the control box at the other end of the middle wall plate of the casing , not in contact with the rear balance frame (15), the front balance frame (13) and the rear balance frame (15) are fixed on the left and right sides by the spring plate (14) The elastic deformation will produce a slight displacement relative to the rear balance frame (15), and the displacement is proportional to the flow of sewage passing through the energy conversion chute (4).

Flow detection mechanism: in Fig. 1, transmission bracket (12), displacement sensor LVDT (11), sensor fixing seat (10); transmission bracket (12) is fixed on the bottom of front balance frame (13), displacement sensor LVDT (11) (with induction coil inside) is fastened to the bottom of the rear gimbal (15) through the sensor holder (10), and one end of the center induction shaft is then fastened to the horizontal displacement transmission bracket ( 12), the horizontal displacement caused by the recoil force when the sewage on the energy conversion chute (5) passes through is transmitted to the center induction shaft of the displacement sensor LVDT (11), so that the other end of the center induction shaft is inside the inner induction coil in its shell The undamped axial movement that produces the same displacement in the middle, the displacement is output by the displacement sensor LVDT (11) and transmitted to the main controller (7) in the form of the internal coil current variation; in Figure 4, the main controller (7) The analog converter (20) performs A/D conversion and is converted into real-time flow by the main control panel (18), and the real-time flow measured at fixed time intervals is accumulated to obtain the total amount of sewage and displayed by the remote control computer (21).

Flow control mechanism: in Fig. 1, stepper motor (1), reduction box (2), stop valve (3), main controller (7); two ends of stepper motor (1) have shafts, one end is equipped with handwheel, and the other One is connected with the gearbox (2), and the gearbox (2) is connected with the stop valve (3); among Fig. 4, the stepper motor controller (19) in the stepper motor (1) and the main controller (7) Electrically connected, controlled by the main control board (18); the opening of the shut-off valve (3) is controlled by the main control board (18) in the production controller (7) according to the detected instantaneous flow value and the sewage flow rate set by the system. Values are compared in real time, through the stepper motor controller (19) to control the positive and negative rotation of the stepper motor (1), when the flow value detected by the main control board (18) is greater than the set value, the stepper motor controller (19) Control the stepper motor (1) turn off the cut-off valve (3) small, otherwise then open it up, the main control board (18) controls the stepper motor through the stepper motor controller (19) in this real-time feedback mode (1) Stabilize the sewage flow near the set value to ensure the stable (quantitative) flow of sewage entering the detector and eliminate the detection error caused by too large flow changes.

Claims (5)

1, a kind of sewerage constant flow detecting system, by stepper motor, reducer casing, stop valve connects successively, stop valve is fixed on outside the casing as inlet, by the energy conversion chute, the power transmission major axis, square balance damper, support is transmitted in horizontal shift, displacement transducer, master controller is linked in sequence and is fixed in the casing, it is characterized in that: the energy conversion chute is fixedlyed connected with power transmission major axis one end, and the hole that the power transmission major axis other end passes on the middle wallboard of casing is fastenedly connected with the square balance damper forward horizontal stand frame central bore that is fixed on the middle wallboard other end of casing; Forward horizontal stand frame bottom is transmitted support one end with horizontal shift and is fastenedly connected, the support other end is transmitted in horizontal shift and horizontal displacement sensors center inductive axis is fastenedly connected, and the horizontal displacement sensors shell is fastenedly connected by the square balance damper back balance frame bottom that holder and back are fastened on the middle wallboard of casing.

2, sewerage constant flow detecting system according to claim 1, it is characterized in that: stepper motor is electrically connected with master controller, be subjected to main controller controls, and two shaft, a dress handwheel, the other end is connected with wheel box, wheel box is connected with stop valve again, the aperture of stop valve is to carry out in real time relatively back control step motor positive and inverse realization by master controller according to the desired value of detected instantaneous delivery value and default, when the detected flow value of master controller greater than setting value, with regard to the control step motor stop valve is turned down, otherwise then open big, master controller is stabilized near the target value set discharge of sewage with the mode control step motor of this real-time feedback, and is stable with the discharge of sewage of guaranteeing to enter detector, eliminates the detection error that causes too greatly because of fluctuations in discharge.

3, sewerage constant flow detecting system according to claim 1, it is characterized in that: the square balance damper forward horizontal stand frame left and right sides is connected with spring steel plate one end, the spring steel plate other end is fastenedly connected with the cubic flat balancing stand left and right sides, back, and wallboard is fastenedly connected in the middle of back balance frame back and the casing.

4, sewerage constant flow detecting system according to claim 1, it is characterized in that: the energy conversion chute does not directly contact with the casing wallboard, just be fixed on the power transmission major axis, the power transmission major axis other end then passes the hole on the middle wallboard of casing, be fastenedly connected with the forward horizontal stand frame central bore that is fixed on the cubic balance damper in the middle wallboard other end of the casing control box, because the forward horizontal stand frame of square balance damper is connected with two sides about the back balance frame is fixed on by latch plate, because the elastic deformation of latch plate can produce a micro displacement with respect to the back balance frame, the discharge of sewage of passing through on displacement and the energy conversion chute is directly proportional when stressed.

5, sewerage constant flow detecting system according to claim 1, it is characterized in that: the displacement transducer shell is fastened on square balance damper back balance frame bottom, one of the center inductive axis then is fastened on horizontal shift fastening bottom the forward horizontal stand frame and transmits on the support, on the energy conversion chute sewage by the time horizontal shift that recoil strength causes be passed on the inductive axis of displacement transducer center, make the undamped axially-movable that produces same displacement in the induced inside coil of inductive axis other end, center in its shell, displacement is exported and is passed to master controller and handle by displacement transducer with the form of displacement transducer inner coil current variable quantity.

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