1. Field of Invention
The present invention is directed to monitor water quality and, more particularly, to a water-monitoring apparatus for detecting water quality parameters at constant depths.
2. Related Prior Art
While developing, the world is encountering a more and more serious problem of pollution. Water pollution could be the worst among all kinds of pollution. More and more pollutants are dumped to reservoirs and open channels from fixed sources, e.g., factories and farms, or from mobile sources, e.g., vehicles. Such pollutants may be released into water directly, or may be washed into the water by rain. Once introduced into the water, such pollutants inevitably increase costs in treating the water and very often harm human bodies, life stock and aquatic lives.
Before any proper measure can be taken to solve the problem of water pollution, by what pollutants and to what extent the water is polluted must be figured out. In other words, various quality parameters of the water must be monitored. Some water analyses are performed manually, however they are cumbersome.
As to continuous water analysis, there have been installed some conventional monitoring stations into which water is automatically pumped through pipes. It, however, is found difficult to have the pipes catch up with the water level changing vigorously from season to season. When the water level becomes too low for the pipes to reach, it is impossible to pump water through the pipes.
To make sure that the water can be monitored continuously, there have been devised some water-monitoring apparatuses in which sensors are carried by means of a buoy tied to a bank or a well by means of a cable. To have the buoy float on the water when the water level is low, a sufficiently long cable is used. However, the cable allows the buoy to drift for a long distance in any direction when the water level is high. As the buoy drifts, the cable often tangles with miscellaneous objects, e.g., twigs. This could seriously affect the operation of the sensors. For example, the buoy and therefore the sensors may be kept away from the water due to the cable tangling with a twig reaching out from the water, thus causing a failure.
To prevent the cable from tangling with miscellaneous objects, there has been devised a length control device in which the cable is wound on a reel operatively connected with a motor. The motor can be activated to rotate the reel to adjust a length of the cable extending from the reel so that the sensors can always be immersed in water. However, the motor consumes a lot of energy.
In addition, to transmit signals from the sensors to a monitoring station, the cable is connected to the monitoring station through a signal relay including a mandrel electrically connected with the cable. The mandrel rotates together with the reel. The signal relay further includes a brush electrically connected with the monitoring station. The brush does not rotate. The mandrel is in rotational engagement with the brush, thus allowing the mandrel to rotate with respect to the brush while allowing the signals to be transmitted from the mandrel to the brush. However, friction between the mandrel and the brush interferes with the rotation of the reel and wears out the brush after serving for a period of time.
Therefore, the present invention is intended to alleviate or even obviate the drawbacks that are encountered in the prior art.
It is the primary objective of the present invention to provide a water-monitoring apparatus capable of automatically tracing water level.
It is another objective of the present invention to provide a water-monitoring apparatus with a tangle-free sensor-carrying cable.
It is another objective of the present invention to provide a water-monitoring apparatus with a sensor-carrying cable of an automatically adjustable length.
It is another objective of the present invention to provide a water-monitoring apparatus with a sensor-carrying cable wound on a reel capable of automatic rotation for adjusting a length of the sensor-carrying cable extending from the reel.
It is another objective of this invention to provide a non-contact signal relay for use in a reel structure to facilitate transmitting electric signals from an electric information source attached to the reel structure to a monitoring station without a rotational intervention.
In accordance with an aspect of the present invention, a water-monitoring apparatus includes a frame installed on a well or a bank by water. A reel is mounted on the frame. A constant torque device is used to exert a constant torque on the reel. A cable including a lower end and an upper end is wound on the reel. A buoy is connected with the cable. A detecting device includes at least one sensor. The detecting device is carried via the buoy and electrically connected with the lower end of the cable. The detecting device is used for detecting at least one water quality parameter. A signal relay is electrically connected with the upper end of the cable for receiving an electric signal from the detecting device.
In accordance with another aspect of the present invention, a non-contact signal relay is used in a water-monitoring apparatus. In the water-monitoring apparatus, a frame is installed in a proper position by water. A reel is mounted on the frame. A cable is wound on the reel so that the reel rotates as the cable travels. The cable includes lower and upper ends. A buoy is connected with the cable. At least one sensor is used to detect a water quality parameter and to produce a signal representative of the water quality parameter. The at least one sensor is carried via the buoy and electrically connected with the lower end of the cable. The reel can be rotated to adjust a length of the cable extending from the reel so that the at least one sensor can always be immersed in the water. The non-contact signal relay includes a first block electrically connected with the at least one sensor and a second block electrically connected with a monitoring station wherein the first and second blocks are connected with each other in a non-contact electric manner.
The first block of the signal relay includes an emitter for emitting the signals. The second block of the signal relay includes a second circuit board attached to the frame and electrically connected with a monitoring station and a receiver installed on the second circuit board for receiving the signals.