Automatic liquid level indicator and alarm system

• US 4,459,584 A
• Filed: 12/21/1981
• Issued: 07/10/1984
• Est. Priority Date: 12/21/1981
• Status: Expired due to Term

• Current Assignee: Marvin R. Clarkson
• Original Assignee: Marvin R. Clarkson
• Inventors: Clarkson, Marvin R.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Myer, Daniel
• Application Number:
  US06/340,528
• Time in Patent Office: 932 Days
• Field of Search: 340/539, 340/616, 340/617, 340/618, 340/619, 340/621, 340/622, 340/623, 340/624, 340/625, 73/308, 73/313, 73/321, 200/84 C, 324/117 H, 137/424, 137/558
• US Class Current: 340/624
• CPC Class Codes: G01F 23/46 using magnetically actuated indicating means
• CPC Class Codes: G08B 21/182 Level alarms, e.g. alarms responsive to variables exceeding a threshold
• CPC Class Codes: Y10T 137/8342 Liquid level responsive indicator, recorder or alarm

Abstract

An automatic liquid level indicator and alarm system (10) that automatically emits an alarm when liquid in a vessel reaches a preselected low or high level. The system (10) is particularly adaptable for use on petroleum storage tanks (50) of the type found on petroleum tank farms. The system (1) comprises a low-level and a high-level permanent magnet (10) (11); a low-level and a high-level magnetic sensor (24) (25); an encoder-RF transmitter (15) (16); an RF receiver-decoder (18) (19); an alpha-numeric display (20) and an audible alarm (21). The magnets (10) (11) are attached to an existing movable tape (31) whose position at any instant is relative to the position of a float (41) within the tank (50). The magnets (10) (11) are located at positions indicative of the preselected low or high level marks. When either magnet (10) (11) is juxtaposed with its respective sensor (24) (25) a signal is transmitted by the encoder-RF transmitter (15) (16) and is received by the RF receiver-decoder (18) (19) located at a remote monitor station. The signal is displayed on the display (20) and simultaneously the alarm (21) is energized to alert station personnel of the incoming signal.

Claims

1. An automatic liquid level indicator and alarm system used with and in combination with an existing apparatus having means to displace a tape from one position to another where said tape displacement is indicative of a change in liquid level, where said system comprises:

(a) a permanent magnet rigidly attached to said tape;

(b) a sensing device having means to sense and emit a signal when said magnet is in juxtaposition with said sensing device;

(c) an encoder electrically connected to said sensing device for encoding the signal emitted from said sensing device;

(d) an RF transmitter electrically connected to said encoder for transmitting the encoded signal;

(e) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(f) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(g) a display device electrically connected to said decoder for visually displaying the decoded signal;

(h) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(i) means for powering said sensing device;

said encoder, said RF transmitter, said RF receiver, said decoder, said display device, and said audible alarm.

11. The system as specified in claims 1, 2, 3, or 4, wherein the means for powering said sensing device, said encoder, and said RF transmitter is by a rechargeable battery pack.

12. The system as specified in claim 11 further comprising a solar-cell panel located on a surface of said RF transmitter where said solar cell panel maintains correct charge on said rechargable battery pack.

14. The system as specified in claims 1, 2, 3, 4, 8 or 9 wherein the means for powering said RF receiver, said decoder, said display device, and said audible alarm is from an a-c power source.

15. The system as specified in claim 14 further comprising a standby rechargeable battery pack and associated circuitry to automatically connect said battery pack into the power circuit in the event of an a-c power failure.

16. The system as specified in claims 1, 2, 3, 4, 8, or 9 wherein said encoder and said RF transmitter are contained in same enclosure.

17. The system as specified in claims 1, 2, 3, 4, 8 or 9 wherein said RF receiver and said decoder are contained in same enclosure.

2. An automatic liquid level indicator and alarm system used with, and in combination with an existing liquid level gauging apparatus, where said apparatus is used for measuring the level of a liquid within a vessel and with said apparatus having a metal tape located and transported within a tube assembly by a set of wheel pulleys, where one end of said tape is connected to a float assembly located within said vessel and where other end is connected to a take-up reel mechanically linked to a mechanism that provides a direct visual reading of the liquid level in said vessel, where said system comprises:

(a) a low-level permanent magnet rigidly attached to said tape;

(b) a high-level permanent magnet rigidly attached to said tape;

(c) a dual sensing device incoporating a low-level sensor and a high-level sensor where said sensors have means to detect a magnetic field and to supply a d-c current when either said low-level magnet or high-level magnet is in juxtaposition with respective said low-level sensor or high-level sensor;

(d) a conduit outlet box attached in-line with said tube assembly and having an opening on one surface sized to accept and attach said dual sensing device;

(e) a tape guide structure rigidly attached to inside and opposite the opening of said conduit outlet box;

(f) an encoder electrically connected to said dual sensing device for encoding the signal emitted from said dual sensing device;

(g) an RF transmitter electrically connected to said encoder for transmitting the encoded signal;

(h) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(i) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(j) a display device electrically connected to said decoder for visually displaying the decoded signal;

(k) a low-level flasher activated by a low-level trigger oscillator that is triggered by a signal from said display device;

(l) a high-level flasher activated by a high-level trigger oscillator that is triggered by a signal from said display device;

(m) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(n) means for powering said sensing device;

said encoder;

said RF transmitter, said RF receiver, said decoder, said display device, and said audible alarm.

5. The system as specified in claims 2, 3 or 4 wherein said low-level magnet is juxtaposed with said low-level sensor when said float is located at its lowest level corresponding to a tank nearly empty condition.

6. The system as specified in claims 2, 3 or 4 wherein said high-level magnet is juxtaposed with said high-level sensor when said float is located at its highest level corresponding to a tank nearly full condition.

7. The system as specified in claims 2, 3 or 4 wherein the means by which said low-level sensor or high-level sensor sense a magnetic field and supply a d-c current is accomplished by each sensor further comprising a magnetically-activated electronic digital switch utilizing the Hall effect for sensing the magnetic field.

3. An automatic liquid level indicator and alarm system used with, and in combination with an existing liquid level gauging apparatus, where said apparatus is used for measuring the level of a liquid within a vessel, and with said apparatus having a tube assembly consisting of a first vertical tube, a horizontal tube, and a second vertical tube, a metal tape located and transported within said tube assembly by a set of wheel pulleys, where one end of said tape is connected to a float assembly located within said vessel and where other end is connected to a take-up reel mechanically linked to a mechanism that provides a direct visual reading of the liquid level in said vessel, where said system comprises:

(a) a low-level permanent magnet rigidly attached to said tape;

(b) a high-level permanent magnet rigidly attached to said tape;

(c) a first sensing device incorporating a low-level sensor having means to detect a magnetic field and to supply a d-c current when said low-level magnet is in juxtaposition with said low-level sensor;

(d) a second sensing device incorporating a high-level sensor having means to detect a magnetic field and to supply a d-c current when said high-level magnet is in juxtaposition with said high-level sensor;

(e) a conduit outlet box attached in line with said second vertical tube and having an opening on one surface sized to accept and attach said first sensing device;

(f) a conduit outlet box attached in line with said first vertical tube and having an opening on one surface sized to accept and attach said second sensing device;

(g) a tape guide structure rigidly attached to inside and opposite the opening of each said conduit outlet box;

(h) an encoder electrically connected to said first sensing device and said second sensing device for encoding the signal emitter from said first and second sensing devices;

(i) an RF transmitter electrically connected to said encoder for transmitting the encoded signal;

(j) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(k) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(l) a display device electrically connected to said detector for visually displaying the decoded signal;

(m) a low-level flasher activated by a low-level trigger oscillator that is triggered by a signal from said display device;

(n) a high-level flasher activated by a high-level trigger oscillator that is triggered by a signal from said display device;

(o) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(p) means for powering said sensing devices, said encoder, said RF transmitter, said RF receiver, said decoder, said display device, and said audible alarm.

4. An automatic liquid level indicator and alarm system used with, and in combination with an existing liquid level gauging apparatus, where said apparatus is used for measuring the level of petroleum stored in a storage tank of the type located on petroleum tank farms, and with said apparatus having a metal tape located and transported within a hermetic tube assembly by a set of wheel pulleys, where one end of said tape is connected to a float assembly located within said tank and where other end is connected to a take-up reel mechanically linked to a mechanism that provides a direct visual reading of the liquid level in said tank, where said system comprises:

(a) a low-level permanent magnet rigidly attached to said tape;

(b) a high-level permanent magnet rigidly attached to said tape;

(c) a dual sensing device incorporating a low-level sensor and a high-level sensor where said sensors have means to detect a magnetic field and to supply a d-c current when either said low-level magnet or high-level magnet is in juxtaposition with respective said low-level sensor or high-level sensor;

(d) a conduit outlet box hermetically attached in-line with said tube assembly and having an opening on one surface sized to accept and hermetically attached said dual sensing device;

(e) a tape guide structure rigidly attached to inside and opposite the opening of said conduit outlet box;

(f) an encoder electrically connected to said dual sensing device for encoding the signal emitted from said dual sensing device, and where electrical connection is spark suppressed;

(g) an RF transmitter electrically connected to said encoder for transmitting the encoded signal, and where electrical connection is spark suppressed;

(h) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(i) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(j) a alpha-numeric display device electrically connected to said decoder for visually displaying the decoded signal;

(k) a low-level flasher activated by a low-level trigger oscillator that is triggered by a signal from said display device;

(l) a high-level flasher activated by a high-level trigger oscillator that is triggered by a signal from said display device;

(m) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(n) means for powering said sensing device, said encoder, said RF transmitter, said RF receiver, said decoder, said display device, and said audible alarm.

8. An automatic liquid level indicator and alarm system used in combination with an existing apparatus having means to displace a tape from one position to another where said tape displacement is indicative of a change in liquid level, where said system comprises:

(a) a switch;

(b) means for tripping said switch when said tape passes said switch;

(c) an encoder, electrically connected to said switch, that emits an encoded signal when said switch is tripped;

(d) an RF transmitter electrically connected to said encoder for transmitting the encoded signal;

(e) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(f) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(g) a display device electrically connected to said decoder for visually displaying the decoded signal;

(h) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(i) means for powering said encoder, said RF transmitter, said RF receiver, said decoder, said display device, and said audible alarm.

9. An automatic liquid level indicator and alarm system used in combination with an existing liquid level gauging apparatus, where said apparatus is used for measuring the level of a liquid within a vessel and with said apparatus having a metal tape located and transported within a tube assembly by a set of wheel pulleys, where one end of said tape is connected to a float assembly located within said vessel and where other end is connected to a take-up reel, where said system comprises:

(a) a switch having a sensitive trip arm;

(b) an outlet box attached in-line with said tube assembly and having an opening on one surface sized to accept and attach said switch;

(c) a plurality of tape-guides each rigidly attached to the inside surface of said outlet box below the plane of said tape whereby said tape guides allow said tape to pass smoothly between each of said tape guides at a constant level with respect to the center of the trip arm of said switch;

(d) a ramp assembly rigidly attached to the inside surface of said outlet box at a side opposite the attach side of said switch;

(e) a switch trip button rigidly attached to the top surface of said tape such that when said tape is moving in a trip direction said button strikes the trip arm of said switch causing said switch to trip and make contact and when said tape is moving in a non-trip direction said button strikes the trip arm of said switch and causes the arm to make contact with and be lifted by said ramp assembly to a sufficient distance that allows said button to slide under the trip arm without causing said switch to make contact;

(f) a switch trip arm restrainment structure rigidly attached to the inside surface of said outlet box between edge of said tape and mounting side of said switch and that is configured to restrain the movement of the trip arm so that when said tape is moving in a non-trip direction said structure in combination with said ramp assembly limits the displacement of the trip arm to prevent said switch from making contact;

(g) an encoder, electrically connected to said switch, that encodes and emits a signal when said switch makes contact;

(h) an RF transmitter electrically connected to said encoder for transmitting the encoded signal;

(i) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(j) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(k) a display device electrically connected to said decoder for visually displaying the decoded signal;

(l) a low-level flasher activated by a low-level trigger oscillator that is triggered by a signal from said display device;

(m) a high-level flasher activated by a high-level trigger oscillator that is triggered by a signal from said display device;

(n) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(o) means for powering said encoder;

said RF transmitter, said RF receiver, said decoder, said display device, and said audible alarm.

10. An automatic liquid level indicator and alarm system used in combination with an existing liquid level gauging apparatus, where said apparatus is used for measuring the level of a liquid within a vessel and with said apparatus having a metal tape located and transported within a tube assembly by a set of wheel pulleys, where one end of said tape is connected to a float assembly located within said vessel and where other end is connected to a take-up reel, where said system comprises:

(a) two fully complemented outlet boxes attached in-line with said in-line tube assembly and where said outlet boxes are displaced from one another by 180 degrees;

(b) two said switch trip buttons rigidly attached to the top surface of said tape where one said button corresponds to a low-level position and where other said button corresponds to a high-level position;

(c) an encoder electrically connected to both of said switches in said outlet boxes via a set of sensitive relays where said encoder encodes a signal when either of said relays is energized by the tripping of either of said switches.

(d) an RF transmitter electrically connected to said encoder for transmitting the encoded signals;

(e) an RF receiver frequency-tuned to receive the encoded signal transmitted by said RF transmitter;

(f) a decoder electrically connected to said RF receiver for decoding the encoded signal;

(g) a display device electrically connected to said decoder for visually displaying the decoded signal;

(h) a low-level flasher activated by a low-level trigger oscillator that is triggered by a signal from said display device;

(i) a high-level flasher activated by a high-level trigger oscillator that is triggered by a signal from said display device;

(j) an audible alarm electrically connected to said decoder that is energized simultaneously with the displaying of said decoded signal; and

(k) means for powering said encoder;

said RF transmitter;

said RF receiver;

said decoder, said display device, and said audible alarm.

13. The system as specified in claims 8, 9, or 10 wherein the means for powering said encoder, and said RF transmitter is by a rechargeable battery pack.

18. The system as specified in claim 10 wherein said encoder is electrically connected to both of said switches in outlet box via a solid-state switching circuit where said encoder encodes a signal when said solid-state switching circuit is enabled by the tripping of either of said switches.