Abstract:
A system for data transmission for an explosive environment comprises an ultrasonic transmitter coupled to a Class 1 device disposed inside an explosive risk zone and adapted to generate an electric signal in response to a predetermined condition, the ultrasonic transmitter being configured to generate and transmit an ultrasonic signal in response to receiving the electric signal, an ultrasonic receiver disposed outside the explosive risk zone configured to receive the ultrasonic signal, and an uplink communication device adapted to communicate an alert to a remote operator in response to the ultrasonic receiver receiving the ultrasonic signal.

Description:
RELATED APPLICATION 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application No. 61/968,138 filed on Mar. 20, 2014. 
     
    
     FIELD 
       [0002]    This disclosure primarily relates to a wireless ultrasonic data transmission system and method for explosive environments. 
       BACKGROUND 
       [0003]    Sensors such as float switches, pressure sensors, gas vapor sensors, etc. that operate within highly explosive environments that contain flammable gases, vapors, or dust with oxygen contained in the surrounding air are subject to very stringent design and certification requirements. The housing containing the electronic devices and circuitry must meet Class 1 Division 1 standards. These housing are typically constructed from solid metal capable of withstanding an internal explosion. Small openings cut or drilled into the housing are subject to very tight design constraints and add considerable cost to implementation. The design is further complicated if wireless communication to the electronics inside the housing is needed. Electromagnetic signals cannot penetrate the metal housing and specially designed Class 1 Division 1 antennas are extremely expensive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a simplified block diagram of an exemplary embodiment of the system and method for wireless ultrasonic data transmission for explosive environments according to the present disclosure; 
           [0005]      FIG. 2  is a simplified data flow diagram of an exemplary embodiment of the system and method for wireless ultrasonic data transmission for explosive environments according to the present disclosure; and 
           [0006]      FIG. 3  is a simplified block diagram of an exemplary embodiment of a component in the system and method for wireless ultrasonic data transmission for explosive environments according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    The disclosure is directed to a system and method  10  for relaying data using ultrasonic transmission for an explosive environment, such as oil and natural gas wells, petroleum refineries, gasoline storage and dispensing areas, dry cleaning plants, utility gas plants and storage areas. These hazardous environments are typically classified as Class I Division 1 locations. Class 1 is defined as a locale that may have flammable vapors and gases present. The system and method described herein are also applicable to Class II locations where combustible dust may be found, and other hazardous environments. Division 1 is defined as an environment in which ignitable concentrations of hazards exists under normal operation conditions and/or where hazard is caused by frequent maintenance or repair work or frequent equipment failure. 
         [0008]    While electromagnetic signals cannot penetrate a metal housing that meets Class 1 Division 1 standards, this design solution proposes using an intermediate wireless communication transport that can. As shown in  FIG. 1 , one or more ultrasonic transmitters  12  are coupled to one or more sensors  14  (e.g., float switches, pressure sensors, and gas vapor sensors) inside an explosive risk zone  16 . Upon activation or triggering a predetermined condition, for example, detection of the presence of a certain substance, a measured fluid level exceeding a predetermined threshold, or a sensed pressure exceeding a predetermined setting, the ultrasonic transmitter  12  turns on and sends an ultrasonic signal  18  that is detected by an ultrasonic receiver  20  placed outside the explosive risk zone  16 . The ultrasonic signal  18  may include data according to a predetermined format and protocol. The data may further include an identifier that uniquely identifies the sensor or ultrasonic transmitter that triggered the transmission. Multiple sensors can be uniquely identified using a number of methods such as modulation techniques, such as AM (Amplitude Modulation), FM (Frequency Modulation), FSK (Frequency-Shift Keying), PM (Phase Modulation), SSB (Single-Sideband Modulation), VSB (Vestigial Sideband Modulation), or QAM (Quadrature Amplitude Modulation) may be used. In an exemplary embodiment, each unique sensor or sensor type is identified by varying the modulation rate using Amplitude Modulation. 
         [0009]    Ultrasonic signals have a limited range. For this reason the ultrasonic receiver  20  is placed just outside the explosive risk zone  16 . The ultrasonic receiver  20  detects and decodes the ultrasonic signal sent by the ultrasonic transmitter  12  inside the explosive risk zone  16 . The ultrasonic receiver  20  is further coupled to a conventional wireless transceiver  22  (housed within a box commonly referred to the as the Bridge) that can retransmit the received sensor data using one or more conventional wireless methods such as cellular (GSM, 3G, 4G, CDMA, LTE, etc.) or satellite communications. Other forms of wireless communications are contemplated herein, such as WiFi, infrared, Bluetooth, etc. Similarly, the ultrasonic receiver  20  may be coupled to wired communication means, such as a landline, Local Area Network, Wide Area network, etc. Future wireless and wired communication protocols and methods are also contemplated. 
         [0010]    As shown in  FIG. 1 , the wireless transceiver  22  is configured to communicate with a base station, eNodeB (also known as a cell tower)  24 , which may communicate the sensor data to a remote monitor or operator  26  (illustrated by a mobile telephone, laptop computer, and server) via the telecommunication network and Internet. 
         [0011]      FIG. 2  is a simplified data flow diagram of an exemplary embodiment of the system and method for wireless ultrasonic data transmission for explosive environments according to the present disclosure. The Class 1 Division 1 sensor  14  detects a predetermined condition, such as the presence of a substance, a fluid level exceeding a preset threshold, a temperature rising above a limit, a fluid pressure being greater than a set point, etc., and generates an electrical signal in response to the detected condition (indicated by numeral  30 ). The electrical sensor signal is received by an ultrasonic transmitter  12  that transmits an ultrasonic signal. The ultrasonic signal may be modulated to convey an identifier that uniquely identifies the sensor that triggered the transmission. The ultrasonic signal is meant for transmission over a short distance to an ultrasonic receiver  20  located just outside of the explosive risk zone. The ultrasonic receiver  20  receives the ultrasonic notification and transmits the notification to an uplink communication device  22  (indicated by numerals  32  and  34 ). The uplink communication device  22  in turn receives the notification and transmits the notification to a remote monitor or operator (indicated by numerals  36  and  38 ). 
         [0012]      FIG. 3  is a simplified block diagram of an exemplary embodiment of an exemplary device or component  40  in the system and method for wireless ultrasonic data transmission for explosive environments according to the present disclosure. For example, the ultrasonic transmitter and/or receiver may be implemented as shown in  FIG. 3 . The device  40  may include a bus  42  or electrical pathway that interconnects a controller or processor  44 , a memory  46 , and a communication interface  48 . The bus  42  enables communication among the various components of device  40 . The processor  44  may include one or more processing units or microprocessors that interpret and execute coded instructions. In other implementations, the processor  44  may be implemented by or include one or more application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or the like. 
         [0013]    The memory  46  may include a random access memory (RAM) or another type of dynamic storage device that stores information and instructions for execution by the processor  44 . The memory  46  may also include a read-only memory (ROM) or another type of static storage device that stores static information and instructions for the processor  44 . The memory  46  may further include other types of magnetic or optical recording medium and its corresponding drive for storing information and/or instructions. As used herein, the term “memory” is broadly to include registers, buffers, and other data constructs configured to hold data. 
         [0014]    The communication interface  48  may include protocol stacks for processing data transmitted via a data protocol now know or to be developed. The communication interface  48  may include multi-band antenna and transceiver devices that enables the device  40  to communicate via across wide bands of radio frequency with other devices and/or systems. The communication interface  48  may further include interfaces, ports, or connectors to other devices. 
         [0015]    As described herein, the device  40  may perform certain operations in response to the processor  44  executing custom and specialized software instructions contained in a computer-readable medium, such as memory  46 . A computer-readable medium may be defined as a physical or logical memory device. A logical memory device may include memory space within a single physical memory device or spread across multiple physical memory devices. The custom software instructions may be downloaded from the Internet, read into memory  46  from another computer-readable medium, or from another device via a communication interface  48 . The specialized software instructions contained in the memory  46  may cause the processor  44  to perform specialized processes described herein. Alternatively, hardwired circuitry may be used in place of or in combination with software instructions to implement processes described herein. Thus, implementations described herein are not limited to any specifically required combination of hardware circuitry and software. 
         [0016]    The concept described in this disclosure is applicable to any situation where there is a defined explosive risk zone of relatively limited size. For example, in an application monitoring pump jacks in oilfield operations, the ultrasonic data transmission may be used to relay important equipment and operational status information. It is vital to monitor the pumps for leaks or spills as well as high or low pressure situations. The conventional practice relies on frequent human inspection or to route the electrical sensor signals through a conduit designed to be compliant with explosive zone requirements. Such conduit designs and implementation are extremely costly. 
         [0017]    In an exemplary deployment of the concept disclosed herein, an ultrasonic transmitter  12  is placed within a float switch to detect a spill in the pump jack. It is also possible to put another transmitter within an over-and-under pressure sensor. When an alarm situation is tripped, a cellular bridge located outside the explosive risk zone receives the alarm condition from the ultrasonic receiver  20 , and determine what type of sensor device has been tripped (e.g., spill or pressure) and sends an alert vial cellular communication in the form of a text message to a backend system or web-based application, which may further relay the text message alert to a pump operator or other personnel via a variety of computing devices such as computer server, laptop computer, and smart mobile telephones, etc. The text message preferably contains the type of triggered alert, the time (timestamp of the sensed condition) and location, and other related data. Other forms of communication now known or future implemented (e.g., email, mobile call) to alert operator personnel are also contemplated. 
         [0018]    The features of the present invention which are believed to be novel are set forth below with particularity in the appended claims. However, modifications, variations, and changes to the exemplary embodiments described above will be apparent to those skilled in the art, and the wireless ultrasonic data transmission for explosive environments described herein thus encompasses such modifications, variations, and changes and are not limited to the specific embodiments described herein.