1、 Intentionally left blank AN AMERICAN NATIONAL STANDARD Specification for Thermoplastic and Thermoset Polymer Material Horizontal End Suction Centrifugal Pumps for Chemical Process ASME B73.5M-1995 American Society of Mechanical Engineers 345 East 47th Street, New York, N.Y. Date of Issuance: Novemb
2、er 30, 1995 This Standard will be revised when the Society approves the issuance of a new edition. There will be no addenda or written interpretations of the requirements of this Standard issued to this edition. ASME is the registered trademark of The American Society of Mechanical Engineers. This c
3、ode or standard was developed under procedures accredited as meeting the criteria for American National Standards. The Consensus Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate. The pro
4、posed code or standard was made available for public review and comment which provides an opportunity for additional public input from industry, academia, regulatory agencies, and the public-at-large. ASME does not “approve,“ “rate,“ or “endorse“ any item, construction, proprietary device, or activi
5、ty. ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent, nor assume any suc
6、h liability. Users of a code or standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Participation by federal agency representative(s) or person(s) affiliated with industry is n
7、ot to be interpreted as government or industry endorsement of this code or standard. ASME accepts responsibility for only those interpretations issued in accordance with governing ASME procedures and policies which preclude the issuance of interpretations by individual vol- unteers. No part of this
8、document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. Copyright 0 1995 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A. (This Foreword is not part of ASME 873.5M-1995.) Advan
9、ces in the technology of polymers have allowed manufacturers to offer- these materials in lieu of or as an alternative to alloy metals. Polymer industrial pumps have been offered since the 1970s. As more pump manufacturers had products available, it was recognized that there were no pump standards f
10、or pressure, temperature, capacity, or mechanical features. In 1986, the ASME B73 Committee established a rule committee to develop a new standard for reinforced composite material horizontal end suction centrifugal pumps for chemical process. This standard was to be for pumps with nonlinear polymer
11、s (excluding solid ceramics and/or carbon). The standard was to have the same envelope, pressure-capacity, and mechanical design features for shaft deflection and bearing life of pumps conforming to ASME B73.1M. The development of this standard progressed rapidly after the 1991 revision of ASME B73.
12、1M was completed. The title was then changed to Specification for Thermoplastic and Thermoset Polymer Material Horizontal End Suction Centrifugal Pumps for Chemical Process. The polymers listed in this Standard are those most commonly used for the chemical process, with the option for manufacturers
13、to offer alternative materials. The pressure- temperature limits are based on the polymers currently available. The limits depend on the concentration and temperature of the specific liquid. As the development of the Standard proceeded, the latest applicable features of ASME B73.1M were added, as we
14、ll as a criterion for outside mechanical seals which is not found in ASME B73.1M. Suggestions for improvement of this Standard will be welcome. They should be sent to The American Society of Mechanical Engineers, Secretary, B73 Committee, 345 East 47th Street, New York, NY 10017. This Standard was a
15、pproved as an American National Standard on July 10, 1995. . 111 Intentionally left blank ASME STANDARDS COMMITTEE B73 Chemical Standard Pumps (The following is the roster of the Committee at the time of approval of this Standard.) OFFICERS R. J. Hart, Chair G. W. Sabol, Vice Chair C. J. Gomez, Secr
16、etary COMMITTEE PERSONNEL A. R. Budris, Alternate, In A-C Pump F. W. Buse, lngersoll Dresser Pump Co. G. C. Clasby, The Duriron Co. R. W. Estep, Rhone-Poulenc AG Co. R. J. Hart, E.I. DuPont de Nemours NOTE: Maximum load is defined as the maximum hydraulic load on the largest impeller operating at an
17、y point on its maximum speed curvc with a liquid specific gravity of 1.0. Consult manufac- turer when liquid specific gravity exceeds 1.0. (b) design load for pump sizes A80 and larger. NOTE: Design load is defined as the maximum hydraulic load on the largest impcller operating within the manufactur
18、ers specified range on its maximum speed curve with a specific gravity of 1.0. Consult manufacturer when liquid specific gravity exceeds 1.0. 4.5.5 Running Clearances. Running clearance must be sufficient to prevent internal rubbing contact at: (a) maximum load for pump sizes AA through A70; (b) des
19、ign load for pump sizes A80 and larger. 4.5.6 Critical Speed. The first lateral critical speed of the rotating assembly shall be at least 120% of the maximum operating speed. 4.5.7 Fillets and Radii. All shaft shoulder radii shall be made as large as practical and finished to reduce additional stres
20、s risers. 4.6 Shaft Sealing 4.6.1 Design. One basic type of sealing cover shall be offered, called a seal chamber. The seal chamber is designed to accommodate mechanical seals only and can be of several designs for various types of seals. The design can include a separate gland plate where required.
21、 4.6.1.1 Outside Mechanical Seal. When cor- rosive liquid has satisfactory lubricating properties, an economic choice is an outside mechanical seal. Expensive metallurgies needed for inside seals can 3 ASME 673.5M-1995 be avoided with an outside seal design. Seal com- ponents in contact with the pro
22、cess liquid can be nonmetallic. Seal chamber pressure is important in determining whether a balanced or unbalanced seal is required. Pressures exceeding seal manufacturers recommended limits may cause leakage of the pumped product to atmosphere. Outside seals are advantageous for pumps with short st
23、uffing boxes. Outside seals are easier to ac- cess for adjustment and troubleshooting. 4.6.2 Seal Chamber. The seal chamber can be cylindrical, tapered, or a backplate design. The ta- pered bore seal chamber shall have a 4 deg. minimum taper open toward the pump impeller. The seal chamber shall be d
24、esigned to incorporate the. detail shown in Figs. 1, 2, 3, or 4. The secondary seal con- tact surface(s) shall not exceed a roughness of 1.6 pm (63 pin.). Seal chamber bore corners and entry holes, such as those used for flushing or venting, shall be suitably chamfered or rounded to prevent damage t
25、o secondary seals during assembly. The seal cham- ber shall include means of eliminating trapped air or gas. Vent connections, when required for this pur- pose, shall be located at the highest practical point; drains, when provided, shall be located at the lowest practical point. The location of pip
26、ing connections to the seal chamber for other functions is optional. The size of piping connections to the seal chamber and seal gland shall be Y4 in. NPT minimum, with Y8 in. NPT preferred. Registers shall maintain the seal chamber concen- tric with the axis of the pump shaft within 0.13 mm (0.005
27、in.) FIM (Full Indicator Movement) and the seal chamber face perpendicular to the axis of the assembled pump, shaft within 0.08 mm (0.003 in.) FIM. Figure 1 shows the recommended seal chamber dimensions. 4.6.2.1 Seal Chamber Flow Modifier. The use of enlarged bore seal chambers can improve process f
28、luid flow around the seal faces. When used in con- junction with ribs, strakes, protrusions, or other de- vices to modify the flow path, service life can be improved dramatically under certain application con- ditions. Industry testing shows that flow modifiers help divert the normal circumferential
29、 flow in the seal chamber to one of balance between axial and circumferential flow. This flow change eliminates damaging vortexes of abrasive particles in the seal chamber while improving lubrication of the mechan- ical seal faces. Flow modifiers effectively remove sol- ids from the seal area that c
30、an cause erosion, purge vapors or entrained gases, and dissipate heat without ASME B73.5M-1995 THERMOPLASTIC AND THERMOSET POLYMER MATERIAL HORIZONTAL END SUCTION CENTRIFUGAL PUMPS FOR CHEMICAL PROCESS 20 1.0 mrn (0.040 in.) 4 Typical Deburred Chamfer Dimension Designation AA-AB A05 - A80 A90 - A1 2
31、0 FIG. 1 CYLINDRICAL SEAL CHAMBER Radial Clearance x Minimum x = 19.05 mm (3/4 in.) x = 22.22 mm (7/8 in.) x = 25.40 mm (1.0 in.) 4 THERMOPLASTIC AND THERMOSET POLYMER MATERIAL HORIZONTAL END SUCTION CENTRIFUGAL PUMPS FOR CHEMICAL PROCESS ASME 873.5M-1995 1.0 mm (0.040 in.) 4 Typical Deburred Chamfe
32、r Dimension Designation Radial Clearance x Minimum AA-AB A05 - A80 A90 - A1 20 X = 19.05 mm (3/4 in.) x = 22.22 mm (7/8 in.) x = 25.40 mm (1.0 in.) FIG. 2 SELF-VENTING TAPERED SEAL CHAMBER 5 ASME 873.5M-1995 THERMOPLASTIC AND THERMOSET POLYMER MATERIAL HORIZONTAL END SUCTION CENTRIFUGAL PUMPS FOR CH
33、EMICAL PROCESS external flushing. Improved mean time between planned maintenance is the benefit of clean and cool running mechanical seal chambers. 4.6.3 Tapered Seal Chamber. Taper bore cham- ber designs with a 4-5 deg. taper offer the maximum heat transfer of seal generated heat to the pumped prod
34、uct. This seal chamber design helps eliminate gas entrainment around the seal during startlstop op- erations. Gas bubbles can limit lubrication of the seal faces and cause a dry running condition. Enlarged taper bore seal chambers also improve seal performance when used in applications where process
35、 fluids are close to their boiling points. 4.6.4 Backplate Seal Chamber. Outside mechan- ical seals are often used with backplate designs and a clamp ring (see Fig. 3). The bore in both these parts is sized to fit the stationary seat and is not controlled by this Standard. Other types of seals (in-
36、side, double, tandem) are used with backplate designs (see Fig. 4). 4.6.5 Seal Chamber Runout. Mechanical seal performance is highly dependent on the runout con- ditions that exist at the mechanical seal chamber. Types of runout having significant effect on seal per- formance include: (a) Seal Chamb
37、er Face Runout. This is a measure of the squareness of the seal chamber face with re- spect to the pump shaft. It is measured by mounting a dial indicator on the pump shaft and measuring the total indicator runout at the face of the seal chamber. The maximum allowable runout is 0.08 mm (0.003 in.) F
38、IM. (See Fig. 5.) (b) Seal Chamber Register Runout. Provisions shall be made for centering the gland with either an inside or outside diameter register. This register shall be concentric with the shaft or sleeve and shall have a total indicator runout reading no greater than 0.13 mm (0.005 in.) FIM.
39、 (See Fig. 6.) (c) ShafrlShafr Sleeve Runout. This is a measure of runout at the shaft or shaft mounted sleeve O.D. with respect to a fixed point in space. It is usually mea- sured by mounting a dial indicator at a fixed point in space, such as the face of the seal chamber, and measuring the FIM run
40、out at the shaft mounted sleeve O.D. The maximum allowable shaft sleeve runout is 0.05 mm (0.002 in.). (See Fig. 7.) 4.6.6 Space Requirements. Space in the various seal chamber designs shall provide for one or more of the following configurations of cartridge or non- cartridge seals: 6 (a) single in
41、side mechanical seals, balanced or un- balanced, with or without a throat restriction device (throat bushing); (b) double seal, balanced or unbalanced, inboard and outboard; (c) outside mechanical seal, balanced or unbal- anced, with or without a throat bushing; (d) tandem seals, either balanced or
42、unbalanced. 4.6.7 Throat Restriction Devices. In single seal applications where seal life is not meeting normal design specifications, the following should be consid- ered. The velocity of the flush needs to be increased to remove particles or fibers from the seal chamber. The sealing fluid pressure
43、 is to be raised to maintain a positive controlled flow into the process. When iso- Iating the seal chamber from the process fluid is nec- essary, an external liquid is to be injected into the seal chamber. In each of these cases a close clearance throat restriction device is required. A typical thr
44、oat restriction device is a replaceable bushing that utilizes a nominal I.D. clearance to the shaft sleeve. Throat bushings are designed to fit stan- dard stuffing box configurations with a throat shoul- der that the bushing can be installed against. Fixed bushings are normally pressed into the stuf
45、fing box core. Floating bushings are mechanically suspended to allow for shaft deflection and closer clearances. 4.6.8 Gland (a) Bolting. Pumps shall be designed for four gland bolts. (b) Gasket. The gland-to-stuffing box gasket or 0- ring used for mechanical seals shall be confined on the atmospher
46、ic side to prevent blowout. Machine surfaces of seal chamber bore, face, and gland may be coated with the base polymer to prevent liquid bypass around the gasket. (c) Materials of Construction (I) The gland material shall be compatible with the liquid pumped. (2) Bolts, studs, and nuts shall be a 30
47、0 series stainless steel or other specified corrosion-resistant material. 4.7 Inserts and Connecting Fasteners Inserts shall be totally encapsulated except for the mating threaded surface. The insert material shall be compatible with the mating fastener. The installed insert shall be capable of bein
48、g tested to 200% of the assembly values appIied to the connecting fasteners or in-service values. Manufacturers shall state nom- inal fastener torque in the instruction manual. If re- THERMOPLASTIC AND THERMOSET POLYMER MATERIAL HORIZONTAL END SUCTION CENTRIFUGAL PUMPS FOR CHEMICAL PROCESS / /-x I R
49、 s 0.81 mm (0.032 in.) ASME B73.5M-1995 / 1.0 mm (0.040 in.) Typical Deburred Chamfer FIG. 3 BACKPLATE WITH CLAMP RING I ASME B73.5M-1995 /-x 1 THERMOPLASTIC AND THERMOSET POLYMER MATERIAL HORIZONTAL END SUCTION CENTRIFUGAL PUMPS FOR CHEMICAL PROCESS R s 0.81 rnrn (0.032 in.) 1.0 mm (0.040 in.) Typical Deburred Chamfer Dimension Designation AA - AB A05 - A80 A90 - A120 Radial Clearance x Minimum x = 19.05 rnm (3/4 in.) x = 22.22 rnrn (7/8 in.) x = 25.40 rnm (1.0 in.) FIG. 4 BACKPLATE WITH SEAL CHAMBE
