Impulse type flow velocity sensor
Technical Field
The utility model belongs to the technical field of hydrological instrument, concretely relates to impulse type flow velocity sensor.
Background
The flow rate refers to the distance that the fluid travels per unit time. The flow velocity measurement has important significance in engineering practice and cognition in nature, the current flow velocity meters for measuring the flow velocity of water flow have more types, and the common flow velocity meters mainly comprise a mechanical flow velocity meter and an ultrasonic flow velocity meter. The mechanical type current meter is mainly a rotor type current meter and can be divided into a propeller type current meter and a cup type current meter. The rotor type current meter is quite common in hydrology test, has numerous models, comprises a small handheld current meter which is mainly used in a laboratory and a large suspended current meter which is mainly used in a river channel, has higher measurement precision and wider measurement range, and is suitable for daily water flow velocity measurement. Ultrasonic flow meters include electric wave flow meters, ADV (acoustic doppler flow meters), ADCP (doppler profile flow meters), and the like, which do not require direct contact with water flow and do not interfere with flow fields, but are complex and expensive. At present, the current flow rate meters on the market are integrally formed and can not be generally used as common sensors, and if the current flow rate meters are connected with a common circuit to form a low-cost and easy-to-use flow rate measuring system, the flow rate measuring system is embedded into underwater equipment such as an underwater robot.
Disclosure of Invention
Not enough to prior art, the utility model provides an impulse type velocity sensor to it is more complicated with the current velocity meter to solve current velocity sensor, is not convenient for and other underwater equipment jointly used problem.
In order to achieve the above purpose, the utility model adopts the following technical proposal:
an impulse type flow velocity sensor comprises a stress plate, a vortex eliminating plate, a dowel bar, a sleeve, a waterproof sleeve, a sealed cabin and a weighing sensor; the stress rod is connected with a dowel bar at the central position, the dowel bar penetrates through the other end of the sleeve to be connected with a weighing sensor, the sleeve is fixed on the side wall of the sealed cabin, the weighing sensor is fixed in the sealed cabin, and a sensor connecting wire of the weighing sensor penetrates out of the sealed cabin; the waterproof sleeve is made of a flexible waterproof film material, one end of the waterproof sleeve is sleeved on the dowel bar, and the other end of the waterproof sleeve is sleeved on the sleeve; the vortex eliminating plate is arranged behind the stress rod in parallel and is connected with the force transmission rod in the center of the vortex eliminating plate.
Preferably, the stress plate and the vortex-eliminating plate are both circular and have the same diameter.
Preferably, the distance between the vortex-eliminating plate and the stress plate is equal to the length of the radius of the stress plate.
Compared with the prior art, the beneficial effects of the utility model are that: the utility model has simple structure, and can adapt to various complex environments such as clear water, muddy water, black and odorous water and the like; the utility model discloses small, light in weight, it is with low costs, convenient installation on other underwater equipment such as underwater robot.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
In the figure: the device comprises a stress plate 1, a vortex eliminating plate 2, a force transmission rod 3, a sealed cabin 4, a sensor connecting wire 5, a waterproof sleeve 6, a sleeve 7 and a weighing sensor 8.
Detailed Description
The present invention will be further explained with reference to the drawings and examples.
Referring to fig. 1, an impulse type flow velocity sensor comprises a stress plate 1, a vortex eliminating plate 2, a force transmission rod 3, a sleeve 7, a waterproof sleeve 6, a sealed cabin 4 and a weighing sensor 8; the stress plate 1 and the vortex eliminating plate 2 are both made of metal sheets with the diameter of 40mm, small holes are formed in the centers of the stress plate 1 and the vortex eliminating plate 2, the dowel bar 3 is made of a stainless steel bar with threads at two ends, the stress plate 1 and the vortex eliminating plate 2 are fixed at one end of the dowel bar 3 through the small holes and nuts, and the distance between the stress plate 1 and the vortex eliminating plate 2 is 20 mm; the sleeve 7 adopts a linear bearing, the size of the sleeve 7 is matched with the thickness of the dowel bar 3, and the dowel bar 3 can smoothly move back and forth in the sleeve 7 with low friction; the waterproof jacket 6 is a flexible jacket in the form of a hollow tube, the top end of the ultrathin latex finger sleeve is cut off in the embodiment, one end of the waterproof jacket 6 is sleeved on the dowel bar 3, the other end of the waterproof jacket is sleeved on the sleeve 6, and the waterproof jacket 6 is fixed on the dowel bar 3 and the sleeve 7 by using a pipe clamp and a sealing adhesive tape so as to prevent water from entering the sealed cabin 4 through a gap between the dowel bar 3 and the sleeve 7; weighing sensor 8 adopts the cantilever beam formula weighing sensor that the range is 300g precision is 0.01g, capsule 4 is cylindrical, adopt stainless steel, weighing sensor 9 is fixed on the inside wall of capsule 4 through corresponding installing support, sensor connecting wire 5 of weighing sensor 8 wears out from capsule 4's reservation aperture, should reserve the aperture and adopt sealed glue to carry out the shutoff after wearing out, it has the round hole to open on capsule 4's the lateral wall, sleeve pipe 7 card is in this round hole, and welded fastening.
The following describes the operation and working principle of the present invention.
This sensor need use with other equipment cooperations, and weighing sensor 8 passes through sensor connecting wire 5 and connects an HX711 chip, and HX711 chip is an AD conversion chip, and it can convert analog voltage signal into digital signal, and HX711 chip is connected with the singlechip again, and the STM32 singlechip can be chooseed for use to the singlechip, is connected with liquid crystal display module and DC power supply on the singlechip.
When the water-flow impact-resistant device is used, the stress plate 1 is opposite to water flow, the direction of the dowel bar 3 is consistent with the direction of the water flow, and the water flow impacts the stress plate 1 vertically. The vortex-eliminating plate 2 plays a role in eliminating water flow vortexes behind the back of the stress plate, so that the water pressure behind the stress plate 1 is closer to hydrostatic pressure, and the water pressure in front of and behind the stress plate 1 is approximately equal. Under the above conditions, according to the momentum theorem, the impact force F of the water flow with the flow velocity u on the force-bearing plate 1 with the radius r is: f ═ ρ π r2βu2In the formula, rho is the water density, pi is the circumference ratio, and beta is the correction coefficient. The impact force received by the stress plate 1 is transmitted to the weighing sensor 8 through the dowel bar 3, and the loss caused by the impact force is very small by the sleeve 7 adopting the linear bearing and the flexible waterproof sleeve 6 in the transmission process. If the mass of the impact force F corresponding to the load cell 8 is M, then: where α F is Mg, α is a loss coefficient during transmission, in this example, close to 1, and g is the acceleration of gravity. Therefore, the flow rate u of the water flow is a function of the mass M as follows: m ═ u2ρπr2Beta alpha/g. Let ρ be 1000kg/m3G is 9.8m/s2And β and α are both taken to be 1, the following can be calculated: the flow rate corresponding to 0.01g is 0.009m/s, and the flow rate corresponding to 300g is 1.53m/s, which shows that the measurement accuracy of the flow sensor in the embodiment can reach 1cm/s, and the measuring range is about 1.5 m/s. If the precision is improved, the method can be realized by increasing the area of the stress plate 1 or improving the precision of the weighing sensor 8; if it is desired to increase the measurement range, the area of the force-bearing plate 1 can be reduced or the range of the load cell 8 can be increased. The output of the weighing sensor 8 is an analog voltage signalThe HX711 chip converts the signal into a digital signal AD value, the AD value has a linear relation with the mass M value, and the mass M has a one-to-one functional relation with the flow velocity u, so that the flow velocity u value also has a one-to-one functional relation with the AD value. In practical application, the utility model discloses after the preparation was accomplished, need in the demarcation basin rate the relation between the AD value of rivers velocity of flow u and the output of weighing sensor 8, according to foretell theoretical analysis and actual conditions, the form of rating the formula is: u ═ aX1/2In the formula, a is a flow coefficient, and X is an AD value. The flow coefficient a can be used for measuring the flow velocity by using the sensor according to the calibration formula after being calibrated, and other equipment can be connected to the single chip microcomputer to realize the combined work of the flow velocity sensor and other equipment, and the other equipment can react according to the flow velocity value measured by the flow velocity sensor.