Virtual accelerator for detecting an alarm condition within a pressurized gas sprinkler system and method thereof

• US 6,357,531 B1
• Filed: 08/03/2000
• Issued: 03/19/2002
• Est. Priority Date: 05/30/2000
• Status: Expired due to Term

• Current Assignee: Systèmes FireFlex, Inc.
• Original Assignee: Systems Fireflex Incorporated
• Inventors: Asselin, Jean-Pierre
• Primary Examiner(s): Scherbel, David A.
• Assistant Examiner(s): Nguyen, Dinh Q.
• Application Number:
  US09/631,775
• Time in Patent Office: 593 Days
• Field of Search: 169/20, 169/17, 169/26, 169/61, 169/60, 169/43, 169/46
• US Class Current: 169/17
• CPC Class Codes: A62C 35/66 Accelerators
• CPC Class Codes: A62C 37/40 with electric connection between sensor and actuator

Abstract

The virtual accelerator is for detecting an alarm condition within a pressurized gas sprinkler system. It has a pressure monitor for monitoring pressure within the pressurized gas sprinkler system, and generating a pressure signal representative of the pressure thereof; a sampler for sampling the pressure signal at a given frequency during a predetermined period of time, and generating a series of pressure values; and a detector for detecting variations of the pressure values, and generating an alarm signal if the variations are within a predetermined range. A method for detecting an alarm condition within a pressurized gas sprinkler system is also proposed.

Claims

1. A virtual accelerator for detecting an alarm condition within a pressurized gas sprinkler system, comprising:

a pressure monitoring means for monitoring pressure within the pressurized gas sprinkler system, and generating a pressure signal representative of the pressure thereof;

sampling means for sampling the pressure signal at a given frequency during a predetermined period of time, and generating a series of pressure values; and

detecting means for detecting variations of the pressure values, and generating an alarm signal if the variations are within a predetermined range, the detecting means further comprising a low pass filter for low pass filtering the variations of the pressure values, and generating a first positive signal if the variations are within a low pass filter range.

2. A virtual accelerator according to claim 1, wherein the detecting means further comprise:

first calculating means for calculating pressure change rates of the pressure signal within the predetermined period of time by means of the pressure values;

second calculating means for calculating a mean value of the pressure change rates;

first comparing means for comparing the mean value with a target value, and generating a second positive signal if the mean value exceeds the target value; and

alarm signal generating means for generating the alarm signal in response to an occurrence of the first and second positive signals simultaneously during the predetermined period of time.

3. A virtual accelerator according to claim 1, wherein the pressure monitoring means is a pressure transducer.

4. A virtual accelerator according to claim 3, wherein the detecting means and the sampling means are embodied in a base controller provided with a software.

5. A virtual accelerator according to claim 4, wherein the pressure transducer is an analog pressure transducer transmitting a continuous analog pressure signal to the base controller.

6. A virtual accelerator according to claim 4, further comprising a console and a master controller connected to the base controller, for controlling communications with an external network and with the console.

7. A virtual accelerator according to claim 6, wherein the console comprises a display unit, an electronic buzzer and interface key switches to allow communication between an operator and the base controller via the master controller.

8. A method for detecting an alarm condition within a pressurized gas sprinkler system, comprising the steps of:

(a) monitoring pressure within the pressurized gas sprinkler system, and generating a pressure signal representative of the pressure thereof;

(b) sampling the pressure signal at a given frequency during a predetermined period of time, and providing a series of pressure values; and

(c) detecting variations of the pressure values, and generating an alarm signal if the variations are within a predetermined range, the step of detecting variations further comprising the step of (i) low pass filtering the variations of the pressure values, and generating a first positive signal if the variations are within a low pass filter range.

9. The method according to claim 8, wherein step (c) further comprises the steps of:

(ii) calculating pressure change rates of the pressure signal within the predetermined period of time by means of the pressure values;

(iii) calculating a mean value of the pressure change rates;

(iv) comparing the mean value with a target value, and generating a second positive signal if the mean value exceeds the target value; and

(v) generating the alarm signal when said first and second positive signals are occurring simultaneously during the predetermined period of time.

10. The method according to claim 9, wherein step (b) comprises the steps of:

storing each value of the series of pressure values in a circular pressure buffer according to a chronological order; and

when the circular pressure buffer is full, removing an oldest pressure value from the buffer, and storing a newest pressure value in the buffer according to a chronological order.

11. The method according to claim 10, wherein, in step (c) (ii), the pressure change rates are calculated by calculating a series of pressure slope values from subsequent pairs of newest and oldest pressure values stored in the pressure buffer, and storing the series of pressure slope values in a slope buffer according to a chronological order.

12. The method according to claim 11, wherein, in step (c) (iii), the mean value is calculated by calculating a mean value of the series of pressure slope values in the slope buffer.

13. The method according to claim 12, wherein, in step (c) (i), the low pass filtering step comprises the steps of:

(A) comparing a newest pressure slope value in the slope buffer with a reference slope value, and;

if the newest pressure slope value is equal or exceeds the reference slope value then;

subtracting a content unit from a virtual reservoir; and

verifying whether the virtual reservoir is empty and if said virtual reservoir is empty then generating an empty reservoir signal;

or else verifying whether the virtual reservoir is not full and if said virtual reservoir is not full then adding a content unit to the virtual reservoir;

(B) comparing the newest pressure value in the pressure buffer with a virtual reservoir pressure value, and;

if the newest pressure value is below the virtual reservoir pressure value then decreasing the virtual reservoir pressure value;

or else comparing the newest pressure value in the pressure buffer with the virtual reservoir pressure value, and if said newest pressure value exceeds the virtual reservoir pressure value then increasing the virtual reservoir pressure value;

storing a pressure difference between the newest pressure value and the virtual reservoir pressure value in a differential buffer;

comparing each pressure difference stored in the differential buffer with a pressure difference target value, and counting a number of these pressure differences that are over said pressure difference target value;

comparing the number of pressure differences that are over the pressure difference target value with a predetermined value, and generating a pressure difference signal if the number exceeds the predetermined value; and

(C) verifying whether the empty reservoir and pressure difference signals are occurring simultaneously during the predetermined period of time and if said empty reservoir and pressure difference signals are occurring simultaneously during the predetermined period of time then generating the first positive signal, or else return to step (a).

14. The method according to claim 11, wherein step (c) further comprises the steps of:

comparing the newest pressure value in the pressure buffer with a minimum pressure reference value, and if the newest pressure value exceeds the minimum preference reference value then;

comparing each pressure slope value stored in the slope buffer with a slope target value, and counting a number of these pressure slope values that are over said slope target value; and

comparing the number of pressure slope values that are over the slope target value with a specific value, and generating the alarm signal if the number exceeds a specific value, or else return to step (a);

or else return to step (a).