DFMD Door Frame Metal Detectors – WALK-THROUGH METAL DETECTORS
Imagine a giant metal archway you walk through at some buildings. That’s a door frame metal detector! It’s like an invisible frisbee scanner, but for metal. It uses electricity to sense hidden metal objects, like knives or guns, on people walking by. When it finds metal, it usually beeps or lights up to alert security. These are common in airports, government buildings, and other places with high security.
Door Frame Metal Detectors – A metal detector is an electronic instrument that detects the presence of metal. Metal detectors are useful for finding metal hidden within objects, or metal objects buried underground. A Door Frame Metal Detector (DFMD) as the name suggests is a metal detector fitted in a door to detect metal that may be hidden on the body of the person passing through this door. This is also known as a “walk-through” metal detector. These are used for security screening at access points in prisons, courthouses, and at airports to detect concealed metal weapons on a person’s body.
The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. If a piece of electrically conductive metal is close to the coil, eddy currents will be induced in the metal, and this produces a magnetic field of its own.
The biggest technical change in detectors was the development of the induction-balance system. This system involves two coils that are electrically balanced. When metal is introduced to their vicinity, they would become unbalanced. What allowed detectors to discriminate between metals was the fact that every metal has a different phase response when exposed to alternating currents.
Security Screening
Metal detector technology was adapted to screen airline passengers. Mining metal detectors housed in a large cylindrical pipe were used to make a commercial walk-through security detector. This eventually led to the development of the rectangular gantry, now standard at airports. Both alternating current and pulse systems are used, and the design of the coils and the electronics has moved forward to improve the discrimination of these systems. It is possible to indicate the approximate height of the metal object above the ground, enabling security personnel to locate the source of the signal. Smaller handheld metal detectors are then used to locate a metal object on a person more precisely. DFMDs are designed for high throughput with fewer unnecessary alarms. Targeted objects, such as guns and knives, are consistently and accurately detected, while personal items such as keys, coins, belt buckles, and eyeglasses can pass through without causing an alarm.
DFMD TYPES
DFMDs are of two types:
Single zone DFMD
Multi-zone DFMD provides multi-zone detection
A Multi-zone DFMD will identify whether the target is on the left side or right side of the person. If an individual walks through the DFMD with a concealed weapon located at their ankles, both the single and multi-zone DFMD will locate the target. The difference between the Single zone DFMD and Multi-zone DFMD is that the multi-zone detector will be able to identify the location of the target, on either the left or right side of the individual.
Multi-zone technology discriminates between miniature handguns and harmless objects like keys and coins
Multi-zone DFMDs deploy the ‘Continuous Wave Multiple Sensor Measurement Technique’ over the commonly used ‘Pulse Induction method’. This increases screening efficiency and cuts operating costs. Multiple zones of detection allow the exact location of concealed weapons to be pinpointed. A display shows if a weapon is located on the left, right, or center of the person being screened and if it is at the ankle, knee, waist, chest, or head height. If more than one weapon is being carried each is detected and its location is shown. During an ensuing manual search, security personnel can immediately target the object, or objects, that created the alarm(s.).
An important feature of horizontal multiple zone technology is its ability to efficiently discriminate between miniature handguns and harmless objects. People being screened can pass through the detector without the inconvenience of having to empty their pockets of normal amounts of keys and coins. Weapons manufactured from steel, various grades of stainless steel, aluminum, zinc alloys, and mixed alloys are detected using a single operating mode.
The technology offers excellent electrical interference rejection, thus eradicating false alarms that halt traffic flows. The equipment is also continuously active, which means that weapons or contraband cannot be passed, slid, or tossed through the detector undetected.
Enhanced Features.
Traffic Counters: DFMDs are now built with intelligent and virtually invisible traffic counters which are integrated inside the coil panels. Counters are bi-directional with a decrease mode. Alarms, people, and alarm rates can all be counted. Remote security management: DFMD data can now be viewed on the desktop. It enables monitoring of passenger information, passenger data collection, and processing with versatile reporting tools, as well as monitoring and management of all parameters of the DFMD.
Collect Statistics: Statistics can be summarized, shared by email, and printed in easy-to-read reports.
Monitors Passenger Flow: Authorized personnel can view the traffic and alarm levels of the DFMDs that are connected to the network. The view gives you a quick overall look at lines with high traffic, helping one to better deploy resources.
Monitors Security: When there is a deviation from the original settings stored in the PC, the operator receives an alert. This feature quickly indicates any misuse or malfunctions of the DFMD and increases the overall security level.
Other Applications:
Most DFMDs have phase-sensitive detection circuits, that allow the user to enhance the sensitivity for a certain group of metals and reduce it for others. DFMDs are designed to detect both Ferrous & Non-Ferrous Metals. With higher sensitivity, they can be used in Jewellery manufacturing units to protect against pilferage. High Sensitivity DFMDs are designed specifically for detecting small ferrous and non-ferrous items, such as disposable prison razors, a piece of razor blades, metal shanks, handcuff keys, detonator caps, jewelry, coins, microprocessors, and memory chips. The use of such DFMDs Door Frame Metal Detectors increases safety in prisons and jails by efficiently detecting small metal objects that can be used as weapons, even when they are hidden in body cavities. They are also deployed in manufacturing and distribution facilities to protect small, valuable assets.
Factors to consider when evaluating a DFMD.
Uniform Detection: It is important to select a detector that gives uniform detection throughout the entire interrogation region. The detection response from a poorly designed conventional detector will not be linear. High-sensitivity hot spots and low-sensitivity regions known as dead spots may be present within different regions of the detection field. The detection response from a particular metal object will vary as it is carried through different sectors of the gate.
Electrical and electromagnetic interference: They can play havoc with their performance and often render them unusable. Interference rejection is what separates quality detectors from others. Quality detectors utilize highly efficient noise inhibition software algorithms. Noise originates from a variety of sources; flickering fluorescent light tubes, computer monitors, photocopiers, two-way radios, etc. The level of ambient noise will vary from location to location. It is advisable to test the DFMD Door Frame Metal Detectors in the location where they will eventually be installed.
Continuously active detection: Always select a detector that is continuously active. At no time should the detection circuitry be deactivated. Under no circumstances should a non-continuously active DFMD be installed in an unmanned automatic entry door system.
Metal Types: For both weapons screening and pilferage prevention the detector must be capable of efficiently detecting a variety of metals in a single operating program.
Object transit speed & Orientation: Irrespective of whether the target object is carried very slowly, quickly, or tossed through the detector it should always be detected. It should also be possible to detect the target irrespective of its orientation.
DFMDs are used for commercial and industrial purposes. Widely applicable in hotels, airports, malls, multiplexes, and various public visiting areas.
For More Information Visit-DFMD