GB2158251A

GB2158251A - Digital stream meter

Info

Publication number: GB2158251A
Application number: GB08507745A
Authority: GB
Inventors: James Martyn Overton
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-04-17
Filing date: 1985-03-26
Publication date: 1985-11-06
Also published as: GB8507745D0; GB8410013D0

Abstract

A digital flowmeter for measuring e.g. the speed of water in a stream or river or of a boat comprises a small underwater impellor unit (4) mounted on a depth indicating rod and connected via a flex to a small digital counter and timer unit. Using the rod the unit can be placed at the desired depth. The impellor unit (4) consists of an impellor (1), with an infra red reflecting white marker on a black background and an infra red transmitter and receiver connected to the timer. The number of revolutions is counted and displayed. This is checked against a calibration table to give the velocity. Wind speed can be measured using a different impellor. <IMAGE>

Description

SPECIFICATION Digital stream meter This invention relates to a Digital Stream Meter.

This invention measures the speed of water in a stream or river and the speed of a boat at a depth determined by a wading rod on to which it is fixed. The measurement is at least 95% accurate and repeatable being obtainable in a simple manner permitting use by school children or serious research students.

Stream meters using an impeller have been in -use for several years but they are heavy, large, expensive, costly to repair, and use the Hall Magnetic Effect for counting as well as not being usable on boats.

The Digital Stream Meter is light, uses small amounts of power from five batteries, has automatic power saving switches in the circuits, and is accurate giving constant repeatable results. The counting mechanism is accurate to over 5000 revolutions in a minute using infra red light projected against the impeller and reflected back to a receiver thus being totally frictionless. An auto-timer is provided that when initiated cuts of the readings after one minute displaying the results on a large digital screen. One person or child operation is therefore possible given highly accurate results. A calibration chart is provided that permits immediate conversion of revolutions of the impeller per minute to metres per second flow of water or kilometers per hour or knots.The unit is easily repaired as all circuits have been designed to permit removal of chips or other components and their replacement without soldering.

The invention will know be described in detail.

The Digital Stream Meter consists of four components:-1. An underwater impeller unit fixed in an adjustable manner to-2. A wading rod one metre long marked every ten centimetres to show depth.-3. The impellor unit is also attached by a lightweight flexible cable to a digital counting mechanism and timer in a case suspended from the operators neck and 4. A conversion chart to enable computation of speed of the water or speed of a boat.

Figure 1 shows the impellor unit which is held at the prescribed depth under water by the wading rod and is connected by a flexible wire to the digital counting mechanism. The impellor unit consists of a hard rigid plastic impellor mounted on a marine stainless steel adjustable shaft and anchored by two lock nuts. The impellor blades are plastic (1), the removable nose cone is black graphited nylon (2) as is the collar (3). Internally there is a P.T. F. E. core that revolves around the marine stainless steel shaft. The nose cone is an internal push fit and the collar is screwed into the plastic impellor up to the P.T.F.E. core.

The main bearing is highly polished marine stainless steel against the graphited nylon nose cone. On the rear of the collar and internal to the main body of the impellor unit (4) is a white mark which reflects infra red light. The main body of the impellor unit is made from anodized aluminium and is drilled to take a flexible cable that transmits the signal to the control unit as well as being drilled to fit over the wading rod. The impellor unit is anchored to the wading rod by a stainless steel thumb screw easily hand tightened (5). To the rear of the plastic impellor and collar the anodized aluminium main body (4) has been drilled to accept an infra red transmitter and receiver which are on the end of the flex leading to the digital counter and preset to be at the correct angle before being embedded in liquid rubber to give a totally waterproof seal.The transmitter and receiver are then encased in a brass tube that fits into the recess cut in the anodized aluminium body at the rear of the collar.

Figure 2 is the anodized aluminium wading rod one metre long and marked every ten centimetres for easy placing of the impellor.

The wading rod passes through the impellor unit and is anchored to it by an easily adjustable thumb screw.

Figure 3 is the digital counting and timer unit. This consists of the counting and timing circuits in a standard plastic component box (1), the digital display (2), an inlet socket for the jack plug on the end of the flex leading from the impellor unit (3), an inlet socket for the mini jack plug leading from the supplementary power supply (4), an on/off switch (5), an inhibit/count three way switch (6) a reset button for the main digital display (7) and a count initiate button (8). Removal, or partial removal of any jack plug breaks the circuit and saves battery power even if the unit is switched on. The entire unit is enclosed in a carrying case that is hung around the neck for ease of operation.

Item 4 a conversion chart from revolutions per minute to metres per second is a seperate printed sheet and is not therefore illustrated.

The digital stream meter works in the following manner. When all the components are connected and the five batteries are inserted the impellor is placed in the stream or over the side of the boat facing the flow of water and at the depth determined by hydraulic theory. Switch 5 is switched on and the reset button 7 is pressed thus returning the digital display to zero. The three way switch 6 is set to the middle position and the meter will count the revolutions of the impellor for any given amount of time. When the operator decides to stop the counter switch 6 is set to position 1 (off). This holds and displays the count.

Should the one minute timer be required then the mini jack plug must be inserted into the rear of the control box (4), switch (5) is set to on, button 7 is pressed to zero the meter, switch 6 is set to the third position and the time initiate button (8) is pressed. The meter will then count for one minute and display the result. Any further readings only require the reset button to be pressed once followed by the timer button and a further minute will be counted.

Claims

CLAIMS 1. The Digital Stream Meter consisting of an underwater impellor unit, a wading rod, a digital count and timer unit plus a calibration chart uses an infra red beam of light transmitted inside the impellor unit main body and thus free of weeds to an impellor blade which is so marked as to cause variations in the reflection of infra red light that activates a digital counting mechanism and timer which records the number of revolutions of the impeller without any direct contact between the impeller and the counting mechanism thus being friction free. 2. The use of an infra red counting mechanism as mentioned in Claim 1 has permitted a flow meter to be constructed of less than half the size and weight of existing meters and a counting/timer circuit to be mounted in a box of less than a third the weight and size of any revious flow meter. 3. The reduction in weight and size obtained by the use of an infra red counting mechanism as described in Claim 1 permits one person including children to operate the Digital Stream Meter with ease. 4. The Digital Stream Meter using an infra red counting mechanism as described in Claim 1 can count to over 5000 revolution per minute accurately and this combined with only one impellor permits the meter to be used for measuring slow streams, rivers or the speed of boats. 5. The Digital Stream Meter with the counting mechanism as described in Claim 1 but using a different shaped impellor and conversion chart will measure wind speed. 6. The Digital Stream Meter has, in addition to the counting mechanism mentioned in Claim 1 an automatic timing circuit which will permit a count irrespective of time or a count to the national standard of one minute and then display the result thus permitting one person operation as mentioned in Claim 3. 7. The circuitry and display involved in the digital counting mechanism as described in Claim 1 uses micro chips in sockets thus it is claimed that there is easy replacement of all major components without soldering. 8. All external electrical inputs into the digital counter and timer as mentioned in Claim 1 and 6 use jack plugs that contain circuitry that automatically cuts of the battery power when they are disconnected even if the main switches are switched on thus it is claimed there is a battery power saving facility. CLAIMS New claims or amendments to claims filed on 1 7 June 1985. Superseded claims 1 to 8 New or amended claims:

1. The Digital Stream Meter, consisting of an underwater non enclosed impellor unit, a wading rod, a digital count and timer unit plus a calibration chart uses an infra red beam of light located and transmitted within the impellor unit main body and thus free of weeds, to the rear of an impellor blade directly without the use of "windows" or reflective surfaces on the impellor blades that would wear or be damaged by placement in an open water situation.The rear of the collar of the impellor, which turns at the same speed as the impellor but is internal to the body of the impellor unit, is so marked as to cause variation in the reflection of infra red light that activates a digital counting mechanism and timer which records the number of revolutions of the impellor per minute without any direct contact between the impellor and the count or timing mechanism thus being friction free. The Digital Stream Meter is therefore capable of measuring with repeatable accuracy the flow of water in a stream, river or by a boat rather than in a confined passage or within a duct or housing.

2. The use of an infra red counting mechanism as mentioned in Claim 1 has permitted a flow meter to be constructed of a very small size and weight and a counting/ timer circuit to be mounted in a box very much smaller in weight and size than any previous flow meter.

3. The reduction in weight and size obtained by the use of an infra red counting mechanism as described in Claim 1 permits one person including children to operate the Digital Stream Meter with ease.

4. The Digital Stream Meter using an infra red counting mechanism as described in Claim 1 can count to over 5000 revolution per minute accurately and this combined with only one impellor permits the meter to be used for measuring slow streams, rivers or the speed of boats.

5. The Digital Stream Meter with the counting mechanism as described in Claim 1 but using a different shaped impellor and conversion chart will measure wind speed in the open rather than in confined tube or housing with the impellor rotating around the shaft not attached to it.

6. The Digital Stream Meter as mentioned in Claim 1 has an automatic timing circuit which will permit a count irrespective of time or a count to the national standard of one minute and then display the result thus per mitting one person operation as mentioned in Claim 3.

7. The circuitry and display involved in the digital counting mechanism as described in Claim 1 uses micro chips in sockets thus it is claimed that there is easy replacement of all major components without soldering.

8. All external electrical inputs into the digital counter and timer as mentioned in Claim 1 and 6 use jack plugs that contain circuitry that automatically cuts of the battery power when they are disconnected even if the main switches are switched on thus it is claimed there is a battery power saving facility.

9. As well as the features mentioned in claim 1 to 8 being unique the combination of features to produce the Digital Stream Meter is unique.