INDIRECT HEATING BOILER WITH A TECHNOLOGICAL HATCH

Abstract

This utility model pertains to heating engineering, specifically to boilers for hot water supply systems. This indirectly heated boiler with a service hatch can be used in hot water supply systems for residential, commercial, and industrial buildings. The technical result is increased heating capacity while maintaining the ability to quickly perform maintenance. The indirectly heated boiler with a service hatch comprises a tank, a coil with inlet and outlet connections, a cold water inlet connection, a hot water outlet connection, and a service hatch. The service hatch is an opening in the tank covered by a lid with three openings in which flasks with tubular electric heaters are secured.

Description

[0001] This utility model pertains to heating engineering, specifically to boilers for hot water supply systems. This indirect heating boiler with a service hatch can be used in hot water supply systems for residential, commercial, and industrial buildings.

[0002] The closest in technical essence is a water heater (patent RU 165216, published 10.10.2016 Bulletin No. 28), which contains a protective outer casing, inside which a water tank is installed. The tank has a number of openings, some of which are intended for the installation of pipes, a heat exchanger coil in the internal cavity of the water tank, a removable lid, while the space between the water tank and the protective outer casing is filled with thermal insulation. An additional removable cover is installed on the protective outer casing. Another removable cover is installed on the water tank. The water tank and removable lid are fastened together using bolts and nuts through corresponding evenly spaced holes made on the flanges of the lid and the water tank. The bolt heads are welded to the underside of the water tank flange. A sealing gasket is located between the flanges.The other openings in the water tank are designed to secure the heat exchanger coil, which has threaded ends. The heat exchanger coil is secured to the outside of the water tank via gaskets and retaining elements.

[0003] This technical solution has several drawbacks. The boiler design makes it difficult to access internal components for maintenance and repair, and can also suffer from uneven temperature distribution within the tank, which reduces overall heat transfer efficiency. The lack of easy access to internal components makes maintenance and repair work difficult. Such designs require significant effort to dismantle, increasing maintenance time and costs. In some cases, such boilers are prone to scale buildup, which reduces efficiency.

[0004] The task that the claimed utility model is aimed at solving is the development of a boiler design with improved performance characteristics.

[0005] The technical result provided by the given set of features is an increase in heating power while maintaining the possibility of quickly performing technical maintenance and repairs.

[0006] The technical result is achieved in that the indirect heating boiler with a process hatch includes a tank, a coil with inlet and outlet pipes, a cold water supply pipe, a hot water outlet pipe, a process hatch, the process hatch is an opening in the tank, closed by a lid, which has three openings in which flasks with tubular electric heaters are fixed.

[0007] The essence of the utility model is explained by drawings, which depict:

[0008] - in Fig. 1 - boiler diagram,

[0009] - Fig. 2 - general view of the cover of the process hatch.

[0010] The device includes a stainless steel tank 1, a coil 2 with inlet 3 and outlet 4 pipes, a cold water inlet 5, a hot water outlet 6, and a service hatch 7 for easy maintenance. The boiler may also include a recirculation system with a connection pipe 8 and a connection point 9 for control and measuring instruments.

[0011] The tank has a 10-layer thermal insulation layer, which reduces heat loss. The thermal insulation layer can be made of polyurethane, basalt fiber, or other similar insulation.

[0012] The access hatch 7 is an opening in the tank, covered by a circular cover 11 with holes 12 around its circumference for fastening nuts and three holes 13 for securing the tubular electric heater bulbs 14. The presence of the access hatch allows for maintenance and repairs without dismantling the boiler or disconnecting it from the piping system.

[0013] Three heating elements are arranged circumferentially on the cover at a 120° angle between their axes, ensuring symmetrical heat distribution, the formation of stable convective flows, and minimizing temperature stratification. The optimal diameter of the boiler access hatch cover is 180-220 mm. Within this diameter, the three heating elements are positioned without mutual thermal interference, providing sufficient clearance for installation, maintaining the cover's strength, and simplifying flange connections.

[0014] The three mounting holes for the heating elements is determined by a combination of thermal, hydrodynamic, and operational factors. For domestic and commercial boilers with a capacity of 150-300 liters, the optimal total electric power of the additional heating element is 6-9 kW, while the standard power of a single heating element is 2-3 kW (single-phase 220 V connection).

[0015] When using two heating elements (2×3 kW=6 kW) for a 200 l boiler, the required energy will be 11.64 kW⋅h, the heating time from heating elements only: 11.64 / 6=1.94 h ≈ 116 minutes, which is not enough for fast heating during peak consumption hours.

[0016] When using three heating elements (3×3 kW=9 kW) for a 200 l boiler, the required energy will be 11.64 kW⋅h, the heating time from the heating elements alone: ​​11.64 / 9=1.29 h ≈ 77 minutes, when operating together with a 15 kW coil (15+9=24 kW), the heating time is 11.64 / 24=0.48 h ≈ 29 minutes, which ensures a reduction in heating time by 35-45%, the ability to operate in emergency mode (from electricity), flexible step-by-step power regulation (3 / 6 / 9 kW).

[0017] Using more heating elements results in excessive load on the electrical network, requires a high-power three-phase connection, places increased demands on cable lines, and increases the cost of electrical equipment. Also, using more than three heating elements requires denser placement, creating turbulent overheating zones, increasing the rate of scale formation, and reducing the service life of the heaters. Furthermore, a large number of heating elements reduces the effective water volume, increases the flange diameter, complicates sealing, and increases mechanical stress. Fewer heating elements create an axial cold water zone, while more elements cause convective flows to overlap, creating localized overheating zones.

[0018] Thus, the number of holes for the heating element flasks was chosen to be three, since this number ensures:

[0019] - achieving the optimal total heating power of 9 kW;

[0020] - uniform distribution of heat flows;

[0021] - minimization of temperature stratification;

[0022] - no local overheating;

[0023] - maintaining the strength characteristics of the tank;

[0024] - possibility of step-by-step power regulation;

[0025] - compliance with permissible loads on household and commercial electrical networks.

[0026] Cover 11 functions as a supporting flange, mounting panel and sealing element.

[0027] The heating elements are independent, replaceable components installed in openings in the access hatch cover and can be replaced without dismantling the tank. The use of heating elements housed in protective flasks, so-called "dry" heating elements, not only increases the overall heating output of the boiler but also improves operational reliability (long and trouble-free operation of the boiler), its maintainability, including reduced maintenance costs, and, consequently, the longevity of the unit. The proposed design completely isolates the heating element from the water, as the heating element is housed in a sealed flask attached to the access hatch cover. Heat transfer from the heating element to the water occurs through the flask wall. This technical solution ensures:

[0028] 1. Minimizing scale formation: Scale forms on the outer surface of the flask, not on the heating element itself, which helps maintain nominal heat transfer and prevents local overheating and burnout of the heating element.

[0029] 2. High maintainability: In case of heating element failure, it can be replaced without opening the tank or draining the water from the system (just turn off the power and remove the heating element from the flask).

[0030] 3. Extended service life: The heating element is protected from contact with water and salt deposits, lasting significantly longer than its counterparts.

[0031] The flasks may be secured to the lid by means of a threaded connection, by bolted connections through a flange, or may be welded to the lid, which is the preferred option, or by any other method known to one skilled in the art.

[0032] The tightness of the lid with installed flasks is ensured by the flange connection of the lid and the sealing of each flask with the heating element using a sealing gasket.

[0033] The access cover is hermetically sealed and secured with nuts. This ensures reliable leak protection while allowing easy removal for inspection or replacement of internal components. The access cover is also equipped with a grounding terminal, ensuring additional operational safety.

[0034] The main distinguishing feature of the utility model is the ability to easily access the inside of the tank for maintenance, such as cleaning, as well as easy installation of additional heating elements through a technological hatch.

[0035] The maintenance hatch is located on the side of the tank, which allows for regular maintenance without having to dismantle the entire device and heating system, which significantly saves time and maintenance costs.

[0036] Using high-quality stainless steel for the tank helps to extend the service life of the device and improve heat transfer.

[0037] The device is used as follows. Before commissioning, the boiler is installed vertically and connected to the utility systems. Pipe 5 is connected to the cold water supply system. Pipe 6 is connected to the hot water supply system. Pipes 3 and 4 of the coil are connected to the heating system. If necessary, pipe 8 is connected to the recirculation system. Temperature and pressure sensors are installed at locations 9. A sealing gasket is installed in the mounting hole on the side of the tank. Cover 11 of the access hatch is aligned with the flange hole of the tank. Bolts or studs are installed through holes 12. Uniformly tighten the nuts in a diagonal pattern to ensure a tight connection. The absence of distortion and gaps is checked. The heating elements are installed in holes 13 of the cover. Bulbs 14 of the heating elements are inserted into the tank. The heating elements are fixed on the cover.An electrical connection is made, with the ground terminal being mandatory. The insulation resistance is checked. After filling the tank with water, a test run is performed.

[0038] To perform maintenance, disconnect the boiler from the power supply, shut off the water supply, drain the water, loosen the mounting nuts, and remove cover 11. Clean the inside of the tank, coil, and flasks to remove scale. After completing the maintenance, reinstall the access panel.

[0039] Below are examples of device implementation.

[0040] The following initial data were used for calculations: initial water temperature 10°C, final water temperature: 60°C, ΔT=50°C, specific heat capacity of water 4.19 kJ / kg°C, water density 1 kg / l. Formula for calculating the amount of heat:

[0041] Q=m⋅c⋅ΔT, where m is the mass of water (kg), c is the specific heat capacity, ΔT is the temperature difference.

[0042] Example 1. Analogue boiler. Tank capacity: 200 l, coil power: 15 kW.

[0043] Required amount of heat: Q=200×4.19×50=41,900 kJ=11.64 kW h, heating time: t=11.64 / 15=0.78 h ≈ 47 minutes.

[0044] Taking into account temperature stratification, scale formation, heat loss, the actual heating time increases by 20-25% and is ≈ 58-60 minutes.

[0045] Example 2. A boiler of the claimed design with a volume of 200 liters.

[0046] The design contains a 15 kW coil and three additional 3 kW heating elements (accessible through a hatch). Total power: 15 + 9 = 24 kW. Theoretical heating time: t = 11.64 / 24 = 0.485 h ≈ 29 minutes. Taking into account losses (5-7%): ≈ 30-31 minutes. Heating time savings compared to similar models: up to 30 minutes (≈ 50%). Additionally, more uniform heating reduces localized overheating of the coil and increases heat exchange efficiency.

[0047] Example 3. A boiler of the claimed design with a volume of 300 liters.

[0048] Coil power: 20 kW, number of heating elements: 3 pcs. 3 kW each, total power: 20 + 9 = 29 kW

[0049] Heat quantity: Q=300 × 4.19 × 50=62,850 kJ=17.46 kWh

[0050] Heating time: t=17.46 / 29=0.60 h ≈ 36 minutes

[0051] For an analog without heating elements: 17.46 / 20 = 0.87 h ≈ 52 minutes

[0052] Reduce heating time - up to 30%.

[0053] Thus, the claimed design provides: increased heating power, reduced hot water preparation time, increased energy efficiency, reduced operating costs, increased maintainability, reduced maintenance labor intensity, extended tank service life, the ability to modernize the boiler without changing its basic design, versatility of use in combined heating systems (the boiler can operate only from electric heating elements, only from an external source, or in a combined mode).

Claims

1. An indirect heating boiler with a process hatch, including a tank, a coil with inlet and outlet pipes, a cold water supply pipe, a hot water outlet pipe, a process hatch, characterized in that the process hatch is an opening in the tank, closed by a lid, which has three openings in which flasks with tubular electric heaters are fixed.

2. An indirect heating boiler with a process hatch according to paragraph 1, characterized in that the flasks are welded to the lid.

3. An indirect heating boiler with a process hatch according to paragraph 1, characterized in that the tank is made of stainless steel.

4. An indirect heating boiler with a process hatch according to paragraph 1, characterized in that the tank has a heat-insulating layer.

5. An indirect heating boiler with a process hatch according to paragraph 1, characterized in that it contains a recirculation system with a connection pipe for it.

6. An indirect heating boiler with a process hatch according to paragraph 1, characterized in that it contains sensors for control and measuring instruments.

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