A tubular heat exchanger is mainly composed of a shell, a plate, heat exchange tubes, a head, and a baffle plate. It can be made of ordinary carbon steel or stainless steel respectively. During heat exchange, a fluid enters from the connecting pipe of the head, flows through the pipe, and exits from the outlet pipe at the other end of the head, which is called the pipe side; Another type of fluid enters through the connecting pipe of the shell and flows out from another connecting pipe on the shell, which is called the shell side.
Fixed tube sheet heat exchanger
Its structure is relatively simple, compact, and cost-effective, but the outside of the pipe cannot be mechanically cleaned. This type of heat exchanger tube bundle is connected to a tube plate, which is welded to both ends of the shell and connected to a top cover. The top cover and shell are equipped with fluid inlet and outlet connections. Usually, a series of baffles perpendicular to the tube bundle are installed outside the tube. At the same time, the connection between the steel pipe and the pipe plate and the outer shell is rigid, while the inside and outside of the pipe are two different temperature fluids. Therefore, when the temperature difference between the tube wall and the shell wall is large, due to the different thermal expansion of the two, a large temperature difference stress is generated, which can cause the tube to twist or loosen from the tube plate, and even damage the heat exchanger. Generally, the temperature difference between the pipe wall and the shell wall is 50 degrees Celsius; When the temperature is above C, for safety reasons, the heat exchanger should have a temperature difference compensation device. But the compensation device (expansion joint) can only be used when the temperature difference between the shell wall and the pipe wall is less than 60-70 degrees Celsius; The situation where the fluid pressure on the C and shell sides is not high. When the pressure on the shell exceeds 0.6Mpa, due to the excessive thickness of the compensation ring, it is difficult to expand and contract, and the effect of temperature difference compensation is lost. Therefore, other structures should be considered.
U-tube heat exchanger
The U-shaped tube heat exchanger has each tube bent into a U-shape and fixed at both ends on the same tube plate. Each tube can freely expand and contract, thus solving the problem of thermal compensation. The tube has at least two passes, the tube bundle can be removed for cleaning, and the tubes can expand freely. Its structure is simple, lightweight, and suitable for high temperature and high pressure conditions.
Immersive snake tube heat exchanger
The heat exchanger with serpentine tubes as heat transfer elements is one of the types of wall mounted heat exchangers. It has a simple structure, easy manufacturing, installation, cleaning and maintenance, low price, and is particularly suitable for cooling high-pressure fluids, so it is still widely used.

Nominal diameter	Number of tubes	Number of pipes	Heat Exchange Area Nominal value/calculated value					Cross sectional area of pipeline channel Flow rate at a flow rate of 0.5m/sec in the pipeline channel m/hr		Nominal pressure
			Pipe length (m)					φ25×2.5
			1500	2000	3000	4000	6000	φ25×2
159	Ⅰ	14	1.51.62	22.17	33.27			0.0044/ 0.0049	7.92/ 8.82	0.25
219	Ⅰ	26	3/3.00	4/4.02	6/6.06	8/8.1		0.0082/ 0.0090	14.76/ 16.20	0.6
	Ⅱ	26	3/3.00	4/4.02	6/6.06	8/8.81		0.0041/ 0.0045	7.38/ 8.01	1.0
273	Ⅰ	44	5/5.08	7/5.18	10/10.26	14/13.72	21/20.63	0.0138/ 0.0152	24.84/ 27.36	1.6
	Ⅱ	40	5/4.62	6/6.19	9/9.33	12/12.47	19/18.76	0.0063/ 0.0069	11.24/ 12.42	2.5
325	Ⅰ	60	7/6.93	9/9.28	14/14.00	19/18.71	28/28.13	0.0188/ 0.0208	33.84/ 37.44	0.6
	Ⅱ	56	6/6.47	9/8.66	13/13.05	17/17.46	36/26.26	0.0088/ 0.0097	15.84/ 17.46	1.0
400	Ⅰ	119	14/13.47	18/18.41	28/27.76	37/37.10	55/55.8	0.0374/ 0.0412	67.32/ 74.16	1.6
	Ⅱ	110	13/12.70	17/17.02	26/25.66	34/34.20	50/51.58	0.0173/ 0.0190	31.14/ 34.20	2.5
500	Ⅰ	185			45/4.15	55/57.68	85/86.74	0.0581/ 0.0641	104.58/ 115.38
	Ⅱ	180			40/41.99	55/57.68	85/86.74	0.0283/ 0.0312	50.94/ 56.16
600	Ⅰ	269			60/62.7	85/83.88	125/126.13	0.0845/ 0.0932	152.10/ 167.76
	Ⅱ	266			60/32.05	80/82.94	125/14.72	0.0418/ 0.0461	75.24/ 83.98
700	Ⅰ	379			90/88.41	120/118.17	175/177.71	0.0091/ 0.1313	214.38/ 236.34
	Ⅱ	358			85/83.51	110/111.62	165/167.85	0.0562/ 0.0620	101.16/ 111.60
800	Ⅰ	511			120/119.20	160/159.16	240/239.60	0.1605/ 0.1770	288.90/ 318.60
	Ⅱ	488			115/113.83	150/152.16	230/228.81	0.0767/ 0.0845	138.06/ 152.10
900	Ⅰ	649			150/151.39	200/202.36	305/304.3	0.2039/ 0.2248	367.02/ 404.46
	Ⅱ	630			145/146.96	195/196.44	295/295.40	0.0990/ 0.1091	178.20/ 196.38
1000	Ⅰ	805			185/187.78	250/251.00	375/377.45	0.2529/ 0.2788	455.22/ 501.74
	Ⅱ	792			185/184.75	245/246.95	370/371.36	0.1244/ 0.1374	223.92/ 246.96