Published by Engineering Team, Shaanxi Qianyi Tuoda Technology Co., Ltd on 2026-08-08
Chemical pressure vessel, storage tank, Reactor equipment, Structure of titanium head and cap, Thickness parameter selection, It directly determines the long-term operation stability of the equipment.many projects due to improper matching selection, Cracking occurs after 1-3 years of equipment use, collapse fault, Cause equipment repair, Replacement or even complete scrapping, Additional construction time and economic losses are incurred.Shaanxi Qianyi Tuoda deeply cultivated Baoji China Titanium Valley for 12 years, focusing onTitanium non-standard equipmentcustomization production, Exposure to a large number of field mismatch cases, Misuse of conventional elliptical heads under high pressure conditions, Blind replacement structure of low pressure storage tank, Butterfly heads replace pressure structures, etc., Are common problems in chemical equipment procurement.This paper systematically disassembles hemispheres, ellipse, butterfly, Performance differences of four types of conical heads, Standard selection process, Subdivision condition adaptation, Real project cases and procurement pit-avoidance points, Procurement of chemical equipment, Technical personnel to provide strong landing type reference.
Core Selection SummaryHead and cap selection around three core dimensions, Matching head structure for pressure bearing according to design, Hemispherical Head Adapted to High Pressure ConditionsAccording to the operating temperature screening structure, high temperature conditions priority elliptical head;Adapt butterfly head according to project budget and working condition.Scientific selection can effectively avoid equipment cracking and collapse failure, and reduce the cost of operation and maintenance and replacement in the later period.
Differences in Structure and Performance of Type I and Type IV Mainstream Heads
Hemispherical head pressure performance is excellent, suitable for high pressure reactor, high pressure vessel core conditions.The spherical structure is uniformly stressed, the stress concentration range is small, the value is low, and the structural stability is outstanding.Under the same diameter and pressure conditions, The wall thickness of hemispherical head is only 50%-60% of that of ordinary elliptical head, Pressure adaptability is stronger, It is the optimum structure for high pressure working conditions of 4.0MPa and above.
1 Elliptical head is a common mainstream structure in the chemical industry, Suitable for most medium pressure vessels, oil storage tanks, Chemical storage tank equipment, pressure equilibrium, Mature processing technology, Adapt to a wide range of scenarios, Comprehensive cost-effective fit the needs of most conventional chemical projects.
Butterfly head processing is convenient, cost controllable, mostly used for low pressure and atmospheric storage tank equipment.Under the same pressure conditions, The required wall thickness of butterfly head is much larger than that of hemispherical head, Thickness difference up to 5-6 times, Only suitable for low pressure conditions, It is forbidden to replace the high-pressure head structure, Avoid equipment hidden trouble caused by insufficient pressure.
Tapered heads focus on adapting process requirements, Multi-use for equipment reduction, Mold bottom solids discharge scenario, Easy material discharge, Moderate pressure performance, Not suitable for high pressure, High temperature and severe working conditions.DN50 and below small diameter equipment port, Preference is given to butt-welded pipe caps, compact structure, convenient installation, Adapt to small diameter sealing conditions.
Two, five-step standardized selection of practical operation process
The first step is to check the equipment design pressure, 4.0MPa and above high pressure conditions, unified selection of hemispherical head;Step 2 Check operating temperature, High temperature environment above 350℃, priority fitting elliptical head, Stable high temperature deformation resistanceIn the third step, according to the equipment volume, the elliptical head is preferred for large storage tanks;The fourth step, combined with the project budget, butterfly head can be selected to control the input cost under low pressure conventional conditions;The fifth step is to match the corrosive medium, discard titanium material under concentrated alkali corrosion condition, and select nickel head to avoid alkali brittleness problem.
Precision adaptation scheme for three or five types of subdivision conditions
High pressure reactors and high pressure vessels rely on the uniform stress characteristics of hemispherical heads to ensure stable high pressure operation;1.0-4.0MPa medium pressure chemical vessel, elliptical head is selected to give consideration to universality and economy;Low pressure storage tanks below 1.0MPa, atmospheric equipment, butterfly heads can meet the use requirements and have higher cost performance;The high temperature deformation resistance of the elliptical head is suitable for long-term operation under high temperature conditions above 350℃;crystal, ejection of compact, Reducing process equipment, Optimized material discharge with conical head, Small diameter closed end fits butt weld cap.
Four, titanium head material subdivision selection points
Seawater, dilute acid weak corrosion conditions, TA2 pure titanium head adaptability is good, is a universal anti-corrosion material;TA10 titanium head is selected to improve corrosion resistance of medium containing bromine ion acetic acid and other medium easy to cause crevice corrosion;Under the condition of concentrated sodium hydroxide and strong alkali, titanium materials are easy to crack due to stress alkali brittleness, so it is necessary to replace N6 and N4 nickel heads;TA2 titanium composite plate structure can be adopted under high temperature steam condition to balance temperature resistance and project cost;TC4 titanium alloy heads are selected to strengthen the overall structural stability when the equipment has higher requirements for structural strength.
5. Real project selection case reference
High pressure reactor 5.0MPa, 200℃ conditions, DN1500, 16mm thick hemispherical head, equipment continuous operation for 5 years stable conditions, no fault hidden danger;Misuse of butterfly head under medium pressure condition of 3.5MPa, Stress cracking occurred after 2 years operation, Long-term stable operation of equipment after replacing 12mm elliptical head0.5MPa atmospheric pressure storage tank with DN3000 butterfly head, put into use for 6 years normal operation;Conical head is configured for bottom discharge of crystallizer to meet material discharge demand, stable production for 4 consecutive years;40% sodium hydroxide 150℃ working condition misuse titanium head, Alkali brittle cracking occurred in one year, After replacing the N6 nickel head, the fault problem was completely solved.
VI. Core points of procurement five-step pit avoidance
Avoid misuse of butterfly head under high pressure condition, Butterfly-shaped structure is easy to produce stress concentration under working conditions above 1.6 MPa, Causing cracking hazardsCheck the actual wall thickness of the head upon arrival to eliminate the problem of insufficient pressure caused by wall thickness shrinkage. The inspection can be completed by ultrasonic thickness measurement;The overall stamping head is preferred to avoid the risk of local corrosion failure caused by splicing welds;It is forbidden to use titanium head under concentrated alkali condition, and nickel head shall be selected to adapt to strong alkali environment.Pay Attention to the Annealing Process of Head Stress Relief, After stamping and forming, annealing at 550-650 DEG C, eliminate residual stress, Avoid stress corrosion hazards.
Seven, hundreds of billions of Tuoda supporting service advantages
Relying on Baoji China titanium valley industry advantages and 12 years of titanium non-standard processing experience, Shaanxi Qianyi Tuoda can provide customers with free head selection service, bonding pressure, temperature, medium, Caliber parameters issue adaptation schemeDN300-DN4000 Full Size Hemisphere, ellipse, butterfly, Tapered heads in stock, stable supply cycleSupport DN4000 large-size overall stamping process, Create high quality head without splice weld, Adapt to all kinds of chemical non-standard equipment customization needs.
written in the end
The core of titanium head and pipe cap selection lies in the matching of working conditions, high pressure selective hemisphere, Elliptical Selection at High Temperature, Low pressure budget controllable butterfly, Change nickel material under strong alkali condition.Accurate selection can effectively avoid equipment cracking, hidden danger of collapse, Reduce late-stage operation and downtime losses, Ensure long-term stable operation of chemical equipment.
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disclaimerSelection of head in this paper, Working condition adaptation content is only for chemical equipment selection reference, The specific parameters shall be calculated and landed in combination with the field working conditions., Not as a basis for contract.Shaanxi Qianyi Tuoda Technology Co., Ltd. reserves the right of final interpretation.
Technical consultation: 15909236031 / 0917-3557966 (Baoji·China Titanium Valley)| Official website: www.sxqytd.com
Data source: GB/T 25198-2010, GB/T 150-2011, ASME BPVC Section VIII-1-2023, HG/T 20569-2013 open standard, updated time: August 8, 2026