Page 22 of Pressure Vessel News

Establishing the Maintenance Interval for Shell and Tube Heat Exchangers

How to establish the maintenance schedule for shell and tube heat exchangers? In alignment with the "Pressure Vessel Safety Technical Supervision Regulations" and considering the operational conditions of the enterprise, a comprehensive assessment suggests a typical maintenance cycle of 2 to 3 years. What are the maintenance criteria for shell and tube heat exchangers? (1) Extraction of the core, cleaning of the tube bundle, and shell. (2) Execution of welding and expansion procedures...

Jul 05, 2021 Industrial News

Identifying the Causes of Internal Leakage in Tubular Heat Exchangers

Causes of Internal Leakage in Tubular Heat Exchangers: 1. Corrosion, perforation, or breakage of heat exchange tubes. 2. Leakage due to corrosion and thinning of the nozzle. 3. Looseness in the expansion joint between heat exchange tubes and tube sheet. 4. Cracks, blowholes, or corrosion perforations at the welding place between tubes and tube sheet. 5. Loose or broken bolts in the small floating head. 6. Damage to the small floating head gasket. 7. Damage to the seal of the small floating head...

Jun 16, 2021 Industrial News

Repairing Leaky Heat Exchange Tubes

What are the situations leading to heat exchanger leakage? Heat exchanger leakage occurs due to cracks and perforations caused by corrosion, wear, scouring, assembly strain, tube defects, or significant wall thickness deviations. How to repair leaking heat exchange tubes? 1. Tube leakage at the nozzle is generally repairable, but internal tube sheet repair is not feasible. 2. If the number of leaking pipes is limited and blocked pipes suffice for production needs, conical metal plugging heads can...

Jun 01, 2021 Industrial News

Identifying the Primary Causes of Plate Heat Exchanger Failures

Under the combined influence of significantly high tube pass pressure and the differential temperature load in the large tube shell pass, the fixed tube sheet heat exchanger fails to meet strength requirements. To address the substantial temperature difference stress, an expansion joint is necessary, but it induces significant stress between the tube and tube sheet under high tube pass pressure, rendering it unable to meet strength conditions. Consequently, alternative heat exchange types, such...

May 17, 2021 Industrial News

Maintaining the Gasket on the Tube Sheet

How to Maintain Tube Sheet Gaskets: For optimal performance, ensure horizontal placement to prevent deformation or damage. Reason for Using Same Material on Both Sides of Tube Sheet Gaskets: Uniform pressure distribution is crucial. With identical bolts on both sides, using different materials can lead to uneven pressure, causing sealing failure. Choosing the same material on both sides ensures consistent pressure and prevents sealing issues.  

May 07, 2021 Industrial News

How to Properly Execute Bolt Fastening for Heat Exchangers?

How is the correct bolt fastening sequence for heat exchanger tube boxes and tube plates achieved? Typically, diagonal and cross-bearing methods are used, and torque wrenches tighten the bolts to the specified torque value in the design. Are the material grades of the fastening bolts and nuts for heat exchanger tube boxes and tube plates the same? No, they differ. The material grade of the fastening bolt is higher than that of the nut. The bolt material has higher hardness to avoid damaging the...

Apr 22, 2021 Industrial News

What Causes Intense Vibration in Heat Exchangers?

Causes of intense heat exchanger vibration: (1) Medium frequency-induced resonance (2) External pipe vibration-induced resonance Addressing severe heat exchanger vibration: (1) Adjusting the flow rate or the natural frequency of the bundle (2) Strengthening the pipe structure to minimize vibration  

Apr 22, 2021 Industrial News

What Causes Excessive Heat Exchanger Resistance Beyond Allowable Limits?

Why does heat exchanger resistance surpass the permissible limit? (1) Filter malfunction (2) Scaling on both interior and exterior surfaces of casing and pipes How to address excessive heat exchanger resistance? (1) Clean or replace the filter (2) Remove scale using jet flow or chemical methods  

Apr 14, 2021 Industrial News

What Causes Inefficiency in Heat Transfer within the Heat Exchanger?

What causes subpar heat transfer in heat exchangers? (1) Scaling on heat exchange tubes (2) Poor water quality, oil contamination, and microbial presence (3) Baffle short circuit Addressing inadequate heat transfer in heat exchangers: (1) Chemical or jet flow cleaning to remove scaling (2) Enhanced filtration and water quality management, along with media purification (3) Replacement of pipe box gasket or partition  

Apr 14, 2021 Industrial News

Causes of Flange Seal Leakage in Heat Exchangers

What causes seal leakage at the heat exchanger flange? (1) Gaskets under pressure, corrosion, or deterioration. (2) Weak, loose, or corroded bolts. (3) Flanges lacking rigidity with sealing surface defects. (4) Non-parallel or misaligned flanges. (5) Poor-quality gaskets. How to address seal leakage at the heat exchanger flange? (1) Tighten bolts and replace the gasket. (2) Upgrade bolt materials, fasten, or replace bolts. (3) Replace or address defects in the flange. (4) Repair or replace the flange....

Mar 25, 2021 Industrial News

Causes of Internal Leakage in Heat Exchangers

What causes inner leakage between two media in the heat exchanger? (1) Corrosion-induced perforation and cracking of heat exchange tubes (2) Cracking of the expansion joint between heat exchange tube and tube plate (3) Seal leakage at the float head flange of heat exchangers (4) Seal leakage of threaded tight-ring type heat exchanger tube plates How to address internal leakage of two media in the heat exchanger? (1) Replace or block the leaking tube. (2) Re-expand (repair welding) or block as needed....

Mar 17, 2021 Industrial News

Common Heat Exchanger Faults and Their Remedies

The common faults and treatment of heat exchangers are shown in Table 2-2.   No. Fault  Cause Solution 1 Two kinds of media mingling together (internal leakage) Corrosion perforation and cracking of heat exchange tubes Cracking of the expansion mouth (welding mouth) of the heat exchange tube and tube plate Sealing leakage of float head flange heat exchangers Sealing leakage of tight-ring type heat exchanger tube plates  Replace or...

Mar 13, 2021 Industrial News