GB2145859A - Lift urine/wetting alarm system - Google Patents

Abstract

A system for the detection of a predetermined level of wetting in lift or other similar areas that is considered damaging activates an alarm unit for prompt action by appropriate personnel to deter, apprehend and rectify the damaging act. The system comprises wetness sensor unit 1, 2 and alarm unit 9, 10, electrical/electronic controls 8, data processes and relays, timers 7, magnetic switches 6, cables and other necessary items. The wetness sensor unit, an important part of the system, consists of two electrical conductive elements, strips 2 and/or perforated plates 1 separated by a gap to form an open circuit in the sensing circuitry. The closing of this gap by continuous wetting liquid, even though momentarily only, will close this circuit and activate the alarm and other circuitry. The amount of this gap separation will determine the amount of wetting require to close the sensing circuit. <IMAGE>

Description

SPECIFICATION Lift urine/wetting alarm system I, NG KEK HOW, of Apartment Block 430, Ang Mo Kio Avenue 3, No. 04-2594, Singapore 2056, a citizen of the Republic of Singapore, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a system for the detection and subsequent activation of the audio and visual alarm unit of the system when the lift car is deliberately wetted by unethical passenger(s). Thus external or outside attention will be aroused in order that the culprit can be identified positively. In this respect, the system shall served as a deterrent to lift wetting, and when the lift has been deliberately wetted, will enable the offender to be detained.

So far no one has yet been able to come up with a device or system which is economical and reliable enough to effectively combat against the deliberate wetting of lift car. Until now, the most common practices against the vandalising of lift car are being confined to the engagement of lift attendents or the installation of a set of television camera in the lift with the corresponding television monitoring screen in the security or guardroom. Nevertheless, the former method incurs high operating costs and of uncertain reliability while the latter method is expensive in capital investment and operating cost. In addition, both these methods of surveillance require roundthe-clock human attention in order to be reliable. Furthermore, the sophisticated T.V. camera can easily be damaged by irresponsible persons.

Whatsoever, the important advantages and benefits that can be offered by my invention shall be set out systematically after the following description of this invention.

In view of the consideration for the best economy and optimum performance, this invention of the lift wetting alarm system shall be designed in two versions, viz: (a) The Simple Version; and (b) The Sophisticated Version Basically, both versions operate on the principle of electrical conductivity through water and/or urine when the normally opened circuit of the wetness sensing unit in the lift car is momentarily closed be substantial and/or continuous deliberate wetting. (Pure water is not a good electrical conductor. However, water normally encountered in our daily living contains impurities and forms a good conductor to electricity).

The Simple Version is designed to form a simple packaged unit to be installed within and around the movable lift car within the concept of low cost, easy installation, easy maintenance, durability and reliable performance. Installation of the Simple Version only require a power supply connection from the existing lift car and will not interfere with the existing lift control systems at the lift motor room above the lift shaft. In other words, the installation of this version is self-contained within and around the movable lift car.

The Sophisticated Version is designed based on similar lines and concept as the Simple Version except that the wetting alarm signal, besides activating the audio and visual alarm unit in the lift car, will simultaneously transmit a signal to the lift control centre at the lift motor room and also a signal or alarm message to the security or guardroom to alert the watchman to the action of detaining the wetting culprit. Modifications shall be made to the existing lift control system so that upon the receiving of the wetting signal from the lift car, the control system shall be set into operation to bring the lift car to a predetermined floor with the lift door remaining shut for a predetermined period of time so as to enable the watchman to reach it before the culprit can get out.

Basically, both versions of the system require the installation of the following units and/or devices as shown in Figure 1 of the accompanying sheet of drawing, viz:- A detachable wetness sensing floor plate 1; A set of wetness sensing wall strips 2 for installation at low level around the walls of the lift car-this strips may be used in conjunction with the floor sensing plate to enhance the wetness sensing unit's performance or shall be used as an alternative to the floor plate sensing unit in cases where the latter cannot be accepted for aesthetic or other reasons (the reliability of performance by strip sensor will depend on the accuracy of prediction or assumption that the majority of deliberate wetting cases are committed against or via the lift wall rather than directly onto the lift floor so as to avoid the wetting liquid from splashing directly onto the offender's legs or trouser); Incoming power supply 3 from existing lift installation; Step-down transformer cum rectifier 4 for the conversion of the incoming power supply to a safe low voltage D.C.

supply to the lift wetting alarm system; A lockable power supply "ON/OFF" switch with indicating light 5 for the isolation of the D.C.

power supply to the system by authorised personnel during car periodical cleaning and maintenance so as to prevent the triggering off of false alarm; A set of magnetic door switches 6 to maintain the alarm when the lift door open at the nearest or preset landing and to cut-out the alarm and reset the complete wetting alarm system to normal standby operating status again so that normal operation of the lift can resume immediately;An adjustable timer switch 7 at the system control cubicle to enable the alarming unit to be deactivated after a preset period of operation should the lift door being not able to close or other reasons-this is to ensure that building occupants will not be disturbed unnecessarily; Wetting alarm system control cubicle 8 (where signal from the wetness sensing unit is processed and/or relayed to activate the other units or the system) housing all necessary electrical and electronic controls of the system; Audio alarm unit or siren 9;A flashing visual alarm indicating panel 10 displaying appropriate message such as the following: "THIS PASSENGER JUST WETTED LIFT"; A set of wetting alarm signalling wires 11 or other wired or wireless transmission devices from the system control cubicle relaying to the lift control centre at the lift motor room above the lift shaft and to be used for the Sophisticated Version only.

The efficient operation of the lift wetting alarm system depends to a large extent on the good design of the wetness sensing unit.

Figure 2 of the accompanying sheet of drawing shows the basic construction of the wetness sensing floor plate unit. It comprises the following items with descriptions as layout below with reference to Figure 2.

This floor wetness sensing unit consists of an upper uniformly perforated plate 1 of any strong and durable material to take the weight, wear and tear of passengers, is placed above another uniformly perforated plate 2 of any strong, durable and good electrical conducting material. These plates are fixed together with suitable supports and fixing devices 3 to form a uniform and parallel gap in between such that any liquid wetted onto the plate will be able to flow freely from the upper plate's perforations, through the gap of the plates and into the perforations of the lower plate. The placing of the two plates are such thatperforations of the upper plate overlaps or superimposes completely by the solid areas of the lower perforated plate.This is to prevent the triggering off of false alarm from the short circuiting of the wetness sensing unit which may be caused by falling conducting pins or objects through the perforations and thereby causing the open circuit between the plate and the conductive floor 7 of the lift car to close. An optional layer of fabric 4 of any suitable material and mesh netting size, will be securely adhered to the top or bottom level of the lower perforated plate to assist in the uniform and even spreading and draining of the wetting liquid through the perforations of the lower plate by virtue of the capillary action of the fabric. The set of perforated plates will be securely rested above the lift floor by regularly spaced isolated supports or by regu larly spaced continuous linear supports 5 of strong, durable and dielectric material over the lift car floor 6.The lift floor 6 if not of metallic construction, shall be laid with a layer of sheet or film of any strong, durable and electrical conducting material 7. The upper perimeter edges of the top perforated plate shall be securely fitted with durable and flexible water resistant plastic 8 or suitable flexible lining for the purpose of effectively channelling of any wetting liquid flowing down against the wall of the lift car into the wetness sensing floor plate for processing.

Under normal standby operating condition.

the wetness sensor forms an open circuit by virtue of the open gap between the lower perforated conducting plate and the conducting lift floor. When small amount of water is sprinkered or dripped momentarily onto the sensing plate (such as water which is brought into the lift car during a rainy day or during marketing), the water will just drip through the plate's perforations onto the lift floor in breaking drips so that the sensing circuit will not be closed. However, when a substantial and/or continuous amount of water or conducting liquid is directed onto the sensing plate, the liquid will flow from the lower perforated plate onto the conductive floor of the lift in a continuous conducting film and thereby closing the mormally opened circuit of the wetness sensing unit to activate the alarm and other circuitry of the system.

The size and spacing of the perforations of the wetness sensing plates together with the distance of separation between these plates and between the plates and the lift floor shall determine within practical limits, the actual amount or degree of wetting to be classified as deliberate wetting.

In the case of the wall mounted wetness strip sensor, which comprise of two parallel strips of conductors of durable material securely installed in a horizontal manner at low level around the non-conductive and water repellent walls of the lift car, the distance of vertical separation between the two conducting strips shall form an open circuit for determining the amount of wetting against or via the lift wall to be classified as a deliberate act.

This is because the closing of this strip sensing circuitry, which activate the alarm and other related units, depends on the amount or rate of wetting against the lift wall to be able to form a continuous conducting film overlaping the two parallel conductive sensing strips.

Whatsoever, the advantages and benefits that can be derived by either of these versions of the lift wetting alarm system are as follow: (a) The floor wetness sensing plates or unit can be designed to blend aesthetically with the interior of the lift car; (b) The floor wetness sensing plate being detachable and renewable, will prolong the effective life of the integral floor of the lift car by taking away the wear and tear from the latter; (c) The floor wetness sensing plate, being perforated, enables particles of dirt and dust to falls through to be temporary collected at a less obvious lower level until the next periodical cleaning session; (d) Sensing floor plate can be removed for washing outside; (e) Round the clock surveiliance by watchman is not required;; (f) This system is more economical and reliable than other methods of combating lift wetting vandalism currently being practiced; (g) System is easy to install, operate and maintain.

The basic principle of operation of the lift wetting alarm system shall hereby be described with references to the electrical schematic layout of the system as shown in Figure 3 of the accompanying sheet of drawing: When the wetness sensor unit 1 is activated by wetting, it will activate the electronic wetness circuit 2 whereby signals will be relayed to the following units and/or circuits to bring them into operation:: 1) The audio and visual alarm unit 7 will be activated into operation until deactivated; 2) The timer delay circuit 3 will be activated to that it will automatically deactivate the alarm system and reset the whole wetting alarm system to normal standby operating status again after a preset period of time, should the magnetic door switch 6 not being able to deactivate the alarm due to any mulfunction of this switch or other reasons; 3) The door switching electronic 4 will be activated to connect up the magnetic door switch 6 and process the operation of the latter; 4) A signal from the door switching electronic 4 will be sent at the same time to the auto reset circuit 5 which will cut-off the alarm and reset the whole wetting alarm system to normal standby operating status upon the closing of the lift door whereby the magnetic door switch 6 will be disconnected again.

The concepts of the invention are: 1) A system comprising of electronic wetness sensing units, alarm, controls, data processes and relays and other necessary items relating to the detection and alarm activation when a predetermined level of wetting, classified as damaging or a deliberate act of vandalism is committed, within the closed or travelling lift car so as to enable the culprit to be identified and apprehended.

2) The Simple Version of this wetting alarm system incorporates magnetic door switch or switches to enable the alarm to continue operating until the lift make its first stop at the landing and to cut-off the alarm only upon the closing of the lift door after the latter had opened. This is to enable the culprit to be identified positively as well as to enable the lift to resume its normal operation with the least delay. The installation of this Simple Version will not interfere with the existing lift control system.

3) The Sophisticated Version is similar in operation to the Simple Version except that it allows the wetting signal to be relayed to the watchman and to the lift control centre enabling necessary modification to be made to the lift control system for the car to be brought down to a predetermined level for a predetermined period of time in order that the watchman can reach and apprehend the culprit before the latter can get out unnoticed.

Claims (3)

1. A system for the detection and alarm of a predetermined level or amount of wetting considered damaging in lift or other similar areas, comprising of wetness sensing and alarm units and/or devices, electrical and/or electronic controls and devices, data processes and relays, timers, magnetic switches, cablings and other necessary items to utilise on the ability of electrical conductivity through water to close the normally open circuit of the wetness sensor unit for the activation of the alarm and other related circuitry.

2. A wetness sensing unit as claimed in claim 1 above, comprising of two electrical conductive elements, strips or plates with or without perforations and separated by a gap to form an open circuit of this wetness sensing circuitry in order that this gap can be closed by any continuous electrical conductive liquid, even though momentarily contacted only, to activate the alarm and other related parts of the circuitry, bearing in mind that the amount of gap separation setting will determine (within practical limits) the degree or amount of wetting to be sensed.

3. A wetting alarm system as claimed in any preceding claim, utilizing the first closing of the lift door, after it has first opened when the wetting alarm is set into active operation by the travelling passenger, to deactivate the alarm operation to enable positive identification of the wetting culprit.