Abstract:
A fluid monitoring apparatus for monitoring a fluid in a fluid mains supply, the apparatus comprising means for connecting the apparatus to the mains supply, a testing chamber, a fluid tester, testing a variable of a fluid in the testing chamber and a purger for purging a volume of fluid from the testing chamber which volume of fluid is substantially larger than the volume of the testing chamber, thereby replacing the fluid in the testing chamber with a new fluid volume.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to fluid monitoring apparatus and particularly, though not exclusively, to mains water monitoring apparatus. The present invention also relates to fluid mains, especially but not exclusively water mains, to which such an apparatus is coupled. The present invention also relates to fluid monitoring methods.  
       BACKGROUND OF THE INVENTION  
       [0002]     Mains water supplies need to be monitored for the well-being of the populous and to assist in the maintenance and upkeep of those supplies. Monitoring of such supplies up to now has been carried out by local inspection. A human operative will visit a mains hydrant, gaining access thereto by a culvert or the like, collect a sample of mains water from the hydrant branch and move on, returning periodically.  
         [0003]     This has several disadvantages. It is intensive in terms of skilled manpower requirements and only tests water in the hydrant branch. Further, for many forms of monitoring water needs to removed from the location for testing as a result of which its properties may change.  
         [0004]     It is an aim of preferred embodiments of the present invention to obviate or overcome a disadvantage of the prior art, whether such disadvantage or prior art is referred to herein or otherwise.  
       SUMMARY OF THE INVENTION  
       [0005]     According to the present invention in a first aspect, there is provided a fluid monitoring apparatus for monitoring a fluid in a fluid mains supply, the apparatus comprising means for connecting the apparatus to the mains supply, a testing chamber, a fluid tester, testing a variable of a fluid in the testing chamber and a purger for purging a volume of fluid from the testing chamber which volume of fluid is substantially larger than the volume of the testing chamber, thereby replacing the fluid in the testing chamber with a new fluid volume.  
         [0006]     Thus fresh fluid can be tested.  
         [0007]     Suitably, the apparatus is suitable for coupling to a hydrant connected to the mains supply.  
         [0008]     Suitably, the apparatus comprises a purge controller for controlling the purger to determine the volume to be purged. Suitably, the apparatus comprises a pressure sensor for measuring the fluid pressure. Suitably, the purge controller uses the measured pressure to determine the period for which the purger should operate. Suitably, the period is determined by comparing the pressure in a look-up table for a suitable purge time. Suitably, the purge controller comprises a microprocessor.  
         [0009]     Suitably, the purger is configured to act for a purge time such that the fluid from the mains supply enters the testing chamber.  
         [0010]     Suitably, the fluid tester comprises a turbidity tester. Suitably, the apparatus comprises an electrical conductivity tester. Suitably, the apparatus comprises a temperature tester.  
         [0011]     Suitably, the apparatus is configured whereby purged fluid is purged from the apparatus to atmosphere.  
         [0012]     Suitably, the apparatus comprises a memory for storing fluid test information. Suitably, the apparatus comprises means to enable data from the memory to be downloaded to an external device.  
         [0013]     Suitably, the apparatus comprises a power cell.  
         [0014]     Suitably, the fluid comprises a liquid. Suitably, the liquid comprises water.  
         [0015]     Suitably, the mains supply is a mains water supply.  
         [0016]     According to the present invention in a second aspect, there is provided a fluid mains to which an apparatus according to the first aspect of the present invention is coupled.  
         [0017]     Suitably, the fluid mains is a liquid mains.  
         [0018]     Suitably, the liquid mains is a water mains.  
         [0019]     According to the present invention in a third aspect, there is provided a method of operating a fluid monitoring apparatus for monitoring a fluid in a fluid mains supply, which method comprises the steps of connecting the apparatus to a mains supply, testing a variable of a fluid in a testing chamber and purging a volume of fluid from the testing chamber which volume of fluid is substantially larger than the volume of the testing chamber, thereby replacing the fluid in the testing chamber with a new fluid volume. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The present invention will now be described, by way of example only, with reference to the drawings that follow; in which:  
         [0021]      FIG. 1  is a perspective illustration of an apparatus according to the present invention attached to a hydrant.  
         [0022]      FIG. 2  is a schematic cross sectional elevation of the apparatus shown in  FIG. 1 .  
         [0023]      FIG. 3  is a schematic perspective view of a turbidity sensor for use in the apparatus show in the preceding figures. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     Referring to  FIGS. 1 and 2  of the drawings that follows, there is shown a mains water supply  2  (as an example of a fluid mains) from which extends a hydrant branch  4  to a hydrant  6 . The hydrant branch  4  can be up to one metre long in practice (though the present invention is not limited to this or any other length).  
         [0025]     Coupled to and mounted on the hydrant  4  is a fluid monitoring apparatus  8  according to a preferred embodiment of the present invention. In this case, the fluid monitoring apparatus is a water monitoring apparatus. The monitoring apparatus  8  is attached to the hydrant stand-pipe screw thread (not shown) by connection means comprising a thread attachment (indicated schematically at  10 ), which is secured to a case  12  of the apparatus  8  closed with a lid  14 . The lid  14  is secured to the case by an attachment nut  16 . Extending from the thread attachment and partially into the branch  4  is a sensor head  18  defining therein a testing chamber  20  into which water from the mains  2  flows. For the purpose of the present invention the hydrant branch  4  extends from the mains supply  2  to the entrance to the testing chamber  20 .  
         [0026]     The sensor head  18  carries turbidity, electrical conductivity and temperature sensors  20 ,  22 ,  24  respectively. These are fluid testers.  
         [0027]     Referring to  FIG. 3  of the drawings that follow, turbidity sensor  20  measures turbidity by using a nephelometric turbidity cell  40 , which measures scattered light at 90° to the emitter with the intensity of the reflected light being proportional to the concentration of particles within the sample. An infra-red light emitting diode (not shown) is mounted behind one of the sapphire glass windows  42 ,  44  and a corresponding detector (not shown) behind the other window  44 ,  42 . This allows, a resolution and accuracy at the lower end of the scale (0-10 Nephelometric Turbidity Unit(NTU)).  
         [0028]     Electrical conductivity is measured to indicate the presence or absence of salts, and is often used as a surrogate measure for the dissolved load within a solution. The electrical conductivity sensor  22  (see also  FIG. 3 ) uses four-pole probes giving a linear output allowing for easier calibration. To some extent, such a sensor self-compensates for algal and particle fouling on the plates ensuring a low drift. For instance this can be a K25 sensor from Sentek Ltd, Braintree, Essex, United Kingdom.  
         [0029]     The temperature sensor  24  is a high accuracy thermistor encapsulated within the electrical conductivity sensor  20 .  
         [0030]     From the sensor head  18  a fluid flow path  28  is defined to an outlet  30 . In a branch of the main fluid flow path  28  there is located a pressure sensor  32 . Part of the flow path is defined by a solenoid valve  34  and another part by a non-return valve  36  before the outlet  30 . The outlet  30  opens to atmosphere.  
         [0031]     The apparatus further comprises a battery powered cell  38  for powering the apparatus  8 .  
         [0032]     Also provided is a microprocessor controller  40  and associated memory  42 , which controller  40  receives signals from the sensors  20 ,  22 ,  24 , and controls the solenoid valve  34 .  
         [0033]     Referring in particular to  FIG. 2 , it is noted that in the branch  4  and the fluid flow path  28  of the apparatus  8  there is a substantial volume of water. In practice this water may not have the same characteristics as the water in the mains supply.  
         [0034]     A mode of operation of this embodiment of the present invention will not be described.  
         [0035]     Controller  40  controls the apparatus  8  to sample the water in the mains supply  2  periodically, say daily. Apart from when carrying out fluid monitoring the apparatus  8  is dormant and has no material effect on the mains supply  2 . When the controller  40  determines a test is to be carried out to monitor the water it receives a signal from the pressure sensor  32  indicative of the water pressure and from a look-up table stored in memory  42  determines a time for which the solenoid valve  34  needs to be open in order to purge sufficient water through the apparatus  8  so that the water in the sensor head  18  is mains water. Thus the solenoid valve  34  acts as a purger and controller  40  as a purge controller. That is, all of the water from the testing chamber  20  back to the water mains  2  has to be purged. The actual purge time required based on the current pressure can be determined empirically.  
         [0036]     The controller  40  then controls the solenoid valve  34  to be opened for the period determined from the look-up table thereby to purge water through the apparatus  8  to atmosphere via the outlet  30 . The solenoid valve  34  is then closed and readings are taken of turbidity, electrical conductivity and temperature from the respective sensors  20 ,  22 ,  24 . These are then stored in the memory  42  associated with the microprocessor controller  40 .  
         [0037]     To download information from the microprocessor  40 , a data outlet (not shown) can be provided or the apparatus can be BLUETOOTH enabled. In either case the data can be collected by an unskilled operative using a Personal Digital Assistant (PDA) or other data logging device. Modem and radio links can also be used.  
         [0038]     The apparatus described herein can be used as a fluid testing apparatus, but is of particular benefit for liquids, especially water.  
         [0039]     Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.  
         [0040]     All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.  
         [0041]     Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.  
         [0042]     The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.