Photocell Curtain or Point, Which One to Buy?

Photocell or elevator eye is a safety device that detects the presence of any obstacle or passenger at the entrance of the elevator and prevents the elevator door from closing as long as there is an obstacle...

Introduction

Photocell or elevator eye is a safety device that detects the presence of any obstacle or passenger at the entrance of the elevator and prevents the elevator door from closing as long as there is an obstacle.

Photocell is actually a sensor that is installed as a transmitter and receiver on both sides of the elevator door. Light beams are sent from the transmitter to the receiver, and if these beams are interrupted by an obstacle and not received by the receiver, the photocell detects the presence of an obstacle and commands the elevator door not to close using an electronic component called a relay.

Two types of photocells are used in elevators:

A) Point Photocell

B) Curtain Photocell

A) Point Photocell

As the name suggests, in this type of photocell, light beams are sent directly from a point by a transmitter eye to a receiver eye. If an obstacle is in the path of these beams, the sensor detects it, and if the obstacle is slightly higher or lower, the point photocell will not be able to detect it.

The transmitter and receiver eyes of the point photocell are actually infrared LEDs placed inside a cylindrical metal body. The standard installation height of the point photocell is 60 to 70 centimeters from the elevator floor. It is necessary to create a 10-millimeter diameter hole in the elevator body at the installation location of these eyes.

The point photocell comes in two models: single-channel and dual-channel. You can read about the difference between single-channel and dual-channel point photocells in an article titled "What is the difference between single-channel and dual-channel point photocells?" on this site.

B) Curtain Photocell

The operation of this photocell is similar to the point photocell, with the difference that the transmitter and receiver eyes are placed from the floor to the ceiling of the elevator door entrance, covering the entire elevator door with light beams. So that if an obstacle or a passenger's body enters the elevator from any point, the door will not close. Therefore, the likelihood of getting caught between the elevator doors is reduced to zero. The detection accuracy of this photocell is much higher than that of the point photocell.

The transmitter and receiver eyes of the curtain photocell are actually infrared LEDs mounted on electronic boards. These electronic boards are placed inside black aluminum blades. These black blades are installed between the elevator door sill and the cabin body. Due to the cross-sectional area of the curtain photocell blades, which are available in models B and A, a distance of approximately 11 millimeters between the sill and the cabin body needs to be considered for these blades. The necessary depth for embedding the photocell between the sill and the cabin is 40 millimeters in model B and 25 millimeters in model A.

Conclusion

Point photocells are cheaper than curtain photocells. Therefore, employers are more inclined to use point photocells. As mentioned above, in point photocells, it is necessary for the obstacle to be precisely positioned at a specific point to prevent the elevator cabin door from closing.

In high-traffic areas, as well as places where pregnant women, elderly, and children pass through, it is recommended to use curtain photocells, which have much higher accuracy compared to point photocells.

Should we buy a curtain or a blind for the window?

PVC plasticizer production

Natural Oval Shaped Diamond

Tree planting project on Thursday, 4th of Aban, 1402.

Awarding the Golden Trophy and Certificate of Appreciation for the Sample Unit of 1403.