Double wall tank is one of the sources of hot water supply for residential or industrial buildings, which in fact acts as an indirect heat exchanger. The design and production of Double wall tanks due to the possibility of bursting in them requires compliance with various standards and should be considered when purchasing. Seven Industrial Group; The manufacturer of Double wall tank and central heating facilities continues to introduce it in full and asks questions such as What is a double wall tank? What is the price of Double wall tank and what are the components of a double wall tank and it will explain its advantages and disadvantages.
What is a double wall tank?
Double wall tank is a set of two cylinders with different sizes that have empty space between them and is used to transfer temperature from hot water to cold water. In other words, the double-walled tank consists of two inner and outer cylinders, in which cold water enters the inner cylinder and hot water produced by the boiler enters the outer cylinder. The temperature difference between the two fluids of the inner and outer parts causes the transfer of temperature and the heating of the inner duct water.
This group of construction water heaters is often installed on the roof and is connected to the engine room and boiler with multiple connections.
How Double wall tank works
The method of working with Double wall tank is not difficult and complicated and it provides hot water for buildings in the most convenient way possible. The hot water produced in the boiler enters the outer cylinder through a designated pipe. Cold water entering from the urban water supply network enters the inner cylinder and at the same time the external source water will move around the inner wall. The temperature difference between the two fluids leads to heating of the internal source water. In the next stage, the water of the internal source is ready for use in residential or industrial environments through a special valve. After losing temperature, the output source water is returned to the boiler to repeat the above process many times.
An important issue in the operation of the double-walled source is the increase in pressure and temperature of the inlet water from the boiler and the high pressure on the source walls, which will be very dangerous. For this reason, drain valves are designed for these conditions to reduce the pressure.
Double wall tank components
To implement and design Double wall tank, several components and connections have been used, each of which has a specific task. In general, Double wall tank components include the following:
Internal and external tank
The most important components in the structure of a double-walled tank are its two cylindrical tanks, which store hot and cold water and convert hot water. The capacity and dimensions set for these tanks depend on the location of the Double wall tank. For example, the dimensions and capacity of a double-walled tank in buildings with 5 residential units and a population of 15 is much smaller than the tanks used in environments with a population of 40.
In addition to the tank capacity, the material used in their body is also very important. In the first step, the body material of both tanks should be selected in such a way that the possibility of perforation, corrosion and cracking in it is minimized. For this reason, hot-dip galvanized steel sheets are used. In addition, it is necessary to consider the diameter of the sheets used in the inner tank more than the outer. Because the internal tank is under more pressure and in case of cracks or holes, it will be very difficult and expensive to repair. In most cases, a diameter of about 4 to 6 mm is chosen for the internal tank and 3 to 5 mm for the outlet. It should be noted, however, that these values may vary depending on the installation location of the double-walled tank.
Double wall tank inlet and outlet valves
In general, 4 inlet and outlet valves are used in the construction of a double-walled tank, two valves for the entry and exit of water and two valves for the entry and exit of boiler water. The water inlet valve of the inner tank is one-way and causes the tap water to enter the tank, and because it is one-way, the probability of water returning to the pipe is zero. The inlet valve of the inner tank is located at the bottom of the tank and the outlet valve is installed above the tank. A valve at the top of the tank is intended for the entry of boiler water into the external tank, and after this water has cooled, it is returned to the boiler from the bottom of the tank.
Tank safety valve
For various reasons, the temperature of the external tank water may exceed the allowable limit or the steam pressure in it may put pressure on the walls, so the safety valve is installed in the lower part of the tank to drain the required amount of water if necessary. This valve opens and closes automatically and is very important in increasing the security of the device.
Double wall tank capacity
One of the most important and main things that need to be considered in the design and production of double-walled tanks is the capacity of the tank. The capacity of these tanks is calculated based on various factors such as the amount of pressure and temperature of water and fluid in the tank, water corrosion coefficient, number of building units and its population. According to the existing standards in this field, the capacity of Double wall tank in different buildings is as follows, but this amount will change according to the conditions.
Residential houses for 5 people need resources with a volume of 189 to 283 liters, and for houses with a population of 10 people, this amount will be 472 liters. In hospital settings, 46 liters per bed and in schools, one to 2 liters per student is required, which is 4.7 liters per office for office staff.
Advantages of using a double-walled tank
For several important reasons, the use of double-walled tanks is widely used in sparsely populated residential environments and industrial workshops, the most important of which are the following:
· Cheap design, production and construction of double-walled tanks compared to other heat exchangers
· No need for a circulator pump
· No pressure drop due to the two-layer tank structure
· Efficiency of 98% in hot water production
Disadvantages of double-walled tank
Despite the many advantages of this type of thermal capacitor, the use of this equipment faces limitations, the most important of which are:
· Due to the lack of easy access to the inner layer of the tank, repairing cracks or holes created in it is very difficult and costly.
· Improper use in environments with high hot water consumption
· High heat loss compared to coiled tank and other types of water heaters
Important points in buying a double-walled tank
The high diversity of double-walled sources indicates that each is suitable for different environments. In other words, not all types of tanks can be used in every environment with different conditions. Therefore, when buying a double-walled tank, it is necessary to pay attention to some important features in them, which are:
· The hull material of both tanks must have good strength and be made of hot-dip galvanized steel sheets.
· Select tank capacity based on hot water consumption. Calculating the volume of a double-walled tank requires expertise and if necessary, you can contact the experts of Seven Industrial Group and benefit from their guidance.
· Note the location and installation of the double-walled tank. To install these tanks, it is better to first consider the foundation and then install it on a strong and impact-resistant base.
Price of double-walled tank
The price of double-walled tank is one of the most important things that most people pay a lot of attention to when buying, and there are ambiguities for them due to the difference in these products. It should be noted that the price of double-walled tank is determined according to the body of the tank, their dimensions and volume, type of connections and product quality. To inquire about the price of a double-walled tank, you can use the communication channels mentioned at the bottom of the page and contact the experts of Seven Industrial Group.
Production of double-walled tank
Seven Industrial Group; Manufacturer of double-walled tanks in different dimensions and capacities, which in all stages of design and construction of these tanks, has considered the required standards and has produced and supplied quality products. The double-walled tank produced in this complex has steel bodies with hot-dip galvanized coating and their repair and installation is done with the latest equipment.
