Optimize the machining process of the baffle plate

This article introduces how to optimize the machining process of the heat exchanger baffle plate using the characteristics of the left and right notch structures of the heat exchanger baffle plate to achieve the effects of saving materials, reducing costs, and improving efficiency.

1. Preface

A heat exchanger can be a separate device, such as a heater, cooler, and condenser; It can also be a component of a certain process equipment, such as a heat exchanger in an ammonia synthesis tower.
Due to the limitations of manufacturing technology and scientific level, early heat exchangers can only use simple structures, with small heat transfer area, large volume, and bulky, such as serpentine heat exchangers. With the development of manufacturing technology, a tube and shell heat exchanger has gradually formed, which not only has a larger heat transfer area per unit volume, but also has good heat transfer effects. It has long been a typical heat exchanger in industrial production.
In the 1920s, plate heat exchangers appeared and were used in the food industry. Heat exchangers made of plates instead of tubes have a compact structure and good heat transfer effect, so they have gradually developed into various forms. In the early 1930s, Sweden first made spiral plate heat exchangers. Next, a plate fin heat exchanger made of copper and its alloy materials was manufactured by brazing in the UK, which was used to dissipate heat from aircraft engines. In the late 1930s, Sweden produced the first plate and shell heat exchanger for use in pulp mills. During this period, in order to solve the heat transfer problem of strongly corrosive media, people began to pay attention to heat exchangers made of new materials.
Around the 1960s, due to the rapid development of space technology and cutting-edge science, there was an urgent need for various efficient and compact heat exchangers. In addition, with the development of stamping, brazing, and sealing technologies, the manufacturing process of heat exchangers was further improved, which promoted the vigorous development and widespread application of compact plate type heat exchangers. In addition, since the 1960s, in order to meet the needs of heat exchange and energy conservation under high temperature and pressure conditions, typical shell and tube heat exchangers have also been further developed. In the mid-1970s, in order to enhance heat transfer, heat pipe heat exchangers were created based on the research and development of heat pipes.

2. Concept of heat exchanger

A heat exchanger is a device that transfers part of the heat of a hot fluid to a cold fluid, also known as a heat exchanger.
In industrial production such as petroleum, chemical, light industry, pharmaceuticals, and energy, it is often necessary to heat or cool low-temperature fluids, vaporize liquids into steam, or condense steam into liquids. These processes are closely related to heat transfer, and can therefore be accomplished through heat exchangers.
With the development of economy, various types and types of heat exchangers have developed rapidly, and heat exchangers with new structures and materials are constantly emerging. In order to meet the needs of development, China has established standards for certain types of heat exchangers and formed a series. A complete heat exchanger should meet the following basic requirements during design or type selection:

• (1) Reasonably achieve the specified process conditions;
• (2) Safe and reliable structure;
• (3) Easy to manufacture, install, operate, and maintain;
• (4) Economically reasonable.

During the manufacturing process of the heat exchanger, the machining process of the heat exchanger baffle plate is optimized using the characteristics of the left and right notch structures of the heat exchanger baffle plate, achieving the same quality effect while achieving the effect of saving materials, reducing costs, and improving efficiency. Taking our company’s manufacturing of three C3 refrigerator condensers E1699/A/B/C for an ethylene plant as an example, we will explain how to optimize the machining process of the heat exchanger baffle plate.

3. E1669A/B/C fixed tubesheet heat exchanger of ethylene plant

• Specifications: Φ1500×8×10740
• Weight: 39783kg

The specification parameters of the tube sheet and baffle plate are shown in Table 1:

Product Name	Left tube sheet	Right tube sheet	Baffle plate	Support plate
Specifications	Φ 1578X 80	Φ 1578X 80	Φ 1492X10 (with left and right notches)	Φ 1492X10
Texture of material	16Mn forging	16Mn forging	Q235-A	Q235-A
Quantity	1 piece	1 piece	18 pieces	1 piece
Tube hole	3259 – Φ 19.25+0.150	3259 – Φ 19.25+0.150	Φ 19.4+0.30	3259 – Φ 19.4+0.30

4. Optimize the machining process of the front baffle plate

• (1) Blanking: δ= 10 Φ 1510 Blanking according to the solid line shown in Figure 1;
• (2) Drill: Drilling of baffle plate 3259 – Φ 19.40+0.3
• (3) Pliers: Clamp with the right tube plate bolt;
• (4) Machining: Machining the outer circle of the baffle Φ 1492-1.2;
• (5) Pliers: Mark in sequence: 2,3,…, 101213,…, 20;
• (6) Scribe: Scribe 12 on the baffle plate of part 2- Φ 14;
• (7) Drill: Drill with right tube plate 12- Φ 14 (right tube plate 12-M12, bottom hole depth 25);
• (8) Remove the pliers;
• (9) Notch: Double Sign Right Missing: 2,4,…, 18,20; Left missing single number: 3,5,7,9,13,15,17,19;
• (10) Milling: Milling the notch according to the scribed line to ensure a dimension of 360;
• (11) Install the clips in sequence.

The solid lines in the following two figures are the blanking dimensions, and the dotted lines are the actual dimensions of the baffle plate:

Figure.1

Figure.2

5. Optimize the machining process of the baffle plate

The following changes have been made to the machining process items 1 and 10 of the optimized front baffle plate:

• (1) Blanking: δ=10Φ1515 Blanking according to the solid line shown in Figure 2;
• (2) Cutting by shearing or wind welding: Use a plate shearing machine to cut or wind welding to cut the gap, ensuring a dimension of 360.

6. Conclusion

The optimization of the machining process for the baffle plate of the heat exchanger has saved material and reduced drilling time. Cutting the gap with a plate shearing machine or using air welding is more efficient than milling the gap, and the benefits generated are very significant.

Author: Zhang Chu