Electric Valves Used in Cement Companies
Oct 05, 2023
Electric valves are an essential component in cement companies, playing a crucial role in the efficient and automated operation of various processes. These valves are designed to control the flow of different materials, such as cement, water, and additives, throughout the production line.
One of the primary applications of electric valves in cement companies is in the transportation and distribution of cement. These valves regulate the flow of cement from storage silos to trucks or railcars for delivery to construction sites. By accurately controlling the amount of cement being dispensed, electric valves ensure that there is no wastage or spillage during loading operations. Electric valves are also used in blending and mixing processes within cement plants. They control the flow rates of raw materials like limestone, clay, and gypsum into grinding mills where they are pulverized into fine powder. The precise regulation provided by these valves ensures consistent quality and composition of the final product.
Furthermore, electric valves are also used to control water supply during concrete production. They regulate the flow rate and pressure of water added to achieve desired consistency and workability. This automation not only improves efficiency but also enhances product quality by maintaining accurate proportions.
There are many types of valves in cement enterprises. According to the driving mode, they can be divided into electric valves, pneumatic valves, hydraulic valves, etc. Various types of drive valves can be used in cement companies.
The structure of electric valves
In cement companies, the commonly used electric valves are as follows:
(1) Electric three-way material distribution valves are generally used for switching different materials during feeding.
(2) Electric gate valves are generally used for material distribution in the chute at the top of the cement silo, unloading materials at the bottom of the silo and switching of feed paths.
(3) Electric arc valves are generally used for unloading at the bottom of the bulk finished product warehouse.
The structure of the electric valve is mainly composed of an electric motor and an actuator. The electric motor is the driving device and the electric (hydraulic) push rod is the actuator. The rotating motion of the electric motor is converted into the linear reciprocating motion of the push rod through the transmission mechanism, thereby driving the opening and closing of the valve.
The electric (hydraulic) push rod generally needs to be controlled from the low-voltage cabinet distribution circuit. The valve body is required to have two positive and negative limit switches, namely POS1 and POS2 (the mechanical or electromagnetic type) to detect the positive and negative position of the valve. When the limit position is reached, the motor will be automatically stopped to play a protective role.
Types of electric actuators
There are many types of electric actuators, and those used by cement companies can be divided into the following three categories according to their control methods:
(1) Proportional adjustment types
The proportional adjustment type is what we often call analog control valves. The actuator receives the 4 to 20 mA signal output from the DCS or regulator. The actuator output rotation angle or displacement is proportional to this signal and automatically completes the adjustment task. Commonly used valves such as the valves that need to continuously adjust the opening of the fan inlet, the flow valves on the bottom of the homogenization warehouse and the unloading chute at the bottom of the cement warehouse, the valves on the process pipelines that need to adjust the air volume, etc., generally use this type of control valve.
(2) Remote control types
The actuator receives the switching signal from DCS or regulators, and the output shaft of the actuator is positioned at any position according to the 4 to 20mA position feedback signal output by the positioning device. This kind of valve is essentially the same as the proportional adjustment type, but it leaves the judgment of position given and feedback to the DCS. The advantage is to save AO points, thereby saving investment. The disadvantage is that there are more failure points and the control program is complex. Currently, cement companies rarely use this type of actuator.
(3) Switch types
The switch type is also called the two-position type. It receives the switching signal from DCS or regulators, and the output shaft of the actuator can only be controlled at two extreme positions: opening and closing. This kind of actuator is generally used with butterfly valves. It is generally used on pipelines that do not need to adjust the opening of the valve. For example, a dust collector has multiple dust collection pipelines. Under each working condition, only one needs to be opened and the other pipelines must be closed.
One of the primary applications of electric valves in cement companies is in the transportation and distribution of cement. These valves regulate the flow of cement from storage silos to trucks or railcars for delivery to construction sites. By accurately controlling the amount of cement being dispensed, electric valves ensure that there is no wastage or spillage during loading operations. Electric valves are also used in blending and mixing processes within cement plants. They control the flow rates of raw materials like limestone, clay, and gypsum into grinding mills where they are pulverized into fine powder. The precise regulation provided by these valves ensures consistent quality and composition of the final product.
Furthermore, electric valves are also used to control water supply during concrete production. They regulate the flow rate and pressure of water added to achieve desired consistency and workability. This automation not only improves efficiency but also enhances product quality by maintaining accurate proportions.
There are many types of valves in cement enterprises. According to the driving mode, they can be divided into electric valves, pneumatic valves, hydraulic valves, etc. Various types of drive valves can be used in cement companies.
The structure of electric valves
In cement companies, the commonly used electric valves are as follows:
(1) Electric three-way material distribution valves are generally used for switching different materials during feeding.
(2) Electric gate valves are generally used for material distribution in the chute at the top of the cement silo, unloading materials at the bottom of the silo and switching of feed paths.
(3) Electric arc valves are generally used for unloading at the bottom of the bulk finished product warehouse.
The structure of the electric valve is mainly composed of an electric motor and an actuator. The electric motor is the driving device and the electric (hydraulic) push rod is the actuator. The rotating motion of the electric motor is converted into the linear reciprocating motion of the push rod through the transmission mechanism, thereby driving the opening and closing of the valve.
The electric (hydraulic) push rod generally needs to be controlled from the low-voltage cabinet distribution circuit. The valve body is required to have two positive and negative limit switches, namely POS1 and POS2 (the mechanical or electromagnetic type) to detect the positive and negative position of the valve. When the limit position is reached, the motor will be automatically stopped to play a protective role.
Types of electric actuators
There are many types of electric actuators, and those used by cement companies can be divided into the following three categories according to their control methods:
(1) Proportional adjustment types
The proportional adjustment type is what we often call analog control valves. The actuator receives the 4 to 20 mA signal output from the DCS or regulator. The actuator output rotation angle or displacement is proportional to this signal and automatically completes the adjustment task. Commonly used valves such as the valves that need to continuously adjust the opening of the fan inlet, the flow valves on the bottom of the homogenization warehouse and the unloading chute at the bottom of the cement warehouse, the valves on the process pipelines that need to adjust the air volume, etc., generally use this type of control valve.
(2) Remote control types
The actuator receives the switching signal from DCS or regulators, and the output shaft of the actuator is positioned at any position according to the 4 to 20mA position feedback signal output by the positioning device. This kind of valve is essentially the same as the proportional adjustment type, but it leaves the judgment of position given and feedback to the DCS. The advantage is to save AO points, thereby saving investment. The disadvantage is that there are more failure points and the control program is complex. Currently, cement companies rarely use this type of actuator.
(3) Switch types
The switch type is also called the two-position type. It receives the switching signal from DCS or regulators, and the output shaft of the actuator can only be controlled at two extreme positions: opening and closing. This kind of actuator is generally used with butterfly valves. It is generally used on pipelines that do not need to adjust the opening of the valve. For example, a dust collector has multiple dust collection pipelines. Under each working condition, only one needs to be opened and the other pipelines must be closed.
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