02177638731 – 02177638732

Manual Bar Screen

1401/10/21

Manual bar screen is one of the most widely used very simple equipment in wastewater treatment that has the ability to remove solids higher than 2 cm. bar screen has a lot of variety and its manual type has the cheapest price and can be installed and used in different environments. Haft Industrial Group; One of the most experienced teams in designing and manufacturing manual and mechanical bar screen, will provide manual bar screen buying guide including manual bar screen price, advantages, disadvantages and how to design manual bar screen.

What is a Manual Bar Screen?

Manual Bar Screen is a screen consisting of several rods located at a certain distance from each other, which is installed in the passage of sewage. Suspended solids such as pieces of wood, bottles will not be able to enter the canal due to contact with this plate. In some examples of this type of litter, mesh plates are used to block the passage of debris in the water. Trash blocking plates are installed in the sewer inlet channel at angles of 30 to 45 degrees and at a maximum depth of 2 meters.

How Manual Bar Screen works

The presence of debris in the wastewater is one of the main causes of damage to wastewater treatment devices and equipment, which ultimately leads to a reduction in their service life. For this purpose, in the entrance of the sewage inlet channels, a kind of mesh plate or rod is installed under the title of manual garbage collector to prevent them from entering the sewage treatment plants. The main difference between this type of garbage collector and mechanical garbage collectors is the type of garbage collected on the bar or mesh plate. In the manual type, human operators are responsible for this. Depending on the amount of pollution in the water, the process of garbage collection will be done in different time periods.

Types of Manual Bar Screen

Manual Bar Screen can be divided based on various factors, the most important of which is the minimum amount of debris that cannot pass through the screen installed at the entrance to the sewer. Based on this, the types of Manual Bar Screen can be divided into two general groups, which are:

fine screen wastewater treatment

As the name implies, stainless steel rods are used in the design of fine screen wastewater treatment, the distance between the rods is 10 to 30 mm. The short distance between the rods in this type of treatment makes it impossible for a large volume of debris in the water to enter the channel.

coarse screen wastewater treatment

In the coarse screen wastewater treatment type, the distance between the rods is considered to be 40 to 100 mm and they are only able to remove large pieces of debris from the sewage. This group of treatments is often installed before the Mechanical Trash Rake Bar Screen to make the second step of removing waste in the sewage easier and less damage to the device.

Benefits of Manual Bar Screen

Despite the design and production of Mechanical Trash Rake Bar Screen, which are very easy to use, but most of the time, their manual type is used. The reason for choosing and buying Manual Bar Screen to remove sewage pollution is its many advantages, the most important of which are:

· High efficiency in different conditions without the need for electricity

· Cost savings due to cheap price and no need for electricity

· Simplicity of Manual Bar Screen design compared to other examples

· Ability to pass high flow of water and sewage through the device

· Create a minimum pressure drop when passing the device

· High efficiency in removing debris and particles in water

· Ability to remove sediment particles from the bottom of the channel

· High resistance to corrosive substances including acid

· Odor control due to the fact that it is located in a closed chamber

· No blockage of dirt traps by grains and particles

Application of Manual Bar Screen

Manual Bar Screen may be used in various industrial and agricultural environments to prevent waste from entering the pump and other equipment. In general, the application of this device includes the following:

Use in treatment plants with a capacity of less than one thousand cubic meters

Used in environments where access to electricity is not possible

Can be used in the pre-purification stage of Mechanical Trash Rake Bar Screen

How to design a Manual Bar Screen?

Manual Bar Screen is designed in such a way that we first consider the size of 7.5 to 15 cm from the inlet pipe of the device channel. The reason for this is that in case of screen clogging, the sewage does not return to the sewage collection system. Here is the basis for designing and building a Manual Bar Screen.

The basics for designing this unit are as follows:

Usually the distance between the bars is considered to be 10 to 50 mm and the width of the bars is considered to be 10 mm.

The velocity of the fluid passing through the rods is considered to be 0.6 to 1.

If the average flow of wastewater is greater than 150 liters per second, the Mechanical Trash Rake Bar Screen is used.

According to the basics; Select the flow rate of the fluid between the rods and then by dividing the average flow rate by the said velocity, the sum of the open surface between the rods is obtained:

We calculate the height of the sewage in the canal from the manning relation in the sewage inlet pipe to the canal and denote it by h1.

In this step, by dividing the surface obtained from the previous step (A) by the height h1, we calculate the total width between the bars b1.

In the next step, by dividing the sum of the open widths of the bars by the width of each bar we have chosen in the basics, the number of open spaces and finally the number of bars is calculated.

Finally, with the help of the obtained values, the width of the B channel that is placed on the bar screen can be calculated:

b 2 is the width of the bars themselves.

In the next steps, the velocity of the fluid before and after the screen as well as the velocity of the fluid between the bars are determined.

First, we calculate the height of the sewer before the screen bars with the help of Bernoulli relation.

Then we calculate the speed of the drain before the rod.

From the above relation, assuming that z2 and the pressure are zero at the beginning and end, the height d2 can be calculated.The velocity in the section before the bars is equal to:

The speed of sewage passing through the bar is equal to:

As the sewage passes through the rod, there is a drop in the sewage pressure, the value of which is calculated from the following equation:

Finally, the height of the sewage after the garbage collector is calculated as follows:

From the above relation d3 is calculated and finally velocity after passing the screen.

The section after the screen is of particular importance because it is to be connected to the next unit. Therefore, a controller is used to control the sewage. In fact, this controller also plays the role of overflow for sewage transfer.

Production and manufacture of Manual Bar Screen

Seven Industrial Group is a manufacturer of manual and mechanical garbage collectors and other wastewater treatment equipment that all stages of design and manufacture of manual and mechanical garbage collectors are carried out under the supervision of engineers and technicians in this field. Before buying the bar screen, the experts of this collection provide the necessary tips and advice according to the installation environment of this equipment to make the best purchase.