Feed concentration and pH effect on arsenate and phosphate rejection

via polyacrylonitrile ultra?ltration membrane

M.R.Muthumareeswaran,Gopal P.Agarwal n

Department of Biochemical Engineering&Biotechnology,Indian Institute of Technology Delhi,Hauz Khas,New Delhi110016,India

a r t i c l e i n f o

Article history:

Received28February2014

Received in revised form

23May2014

Accepted24May2014

Available online2June2014

Keywords:

Pore size distribution

Surface roughness

Volumetric charge density

Arsenate rejection

Phosphate rejection

a b s t r a c t

The aim of the present work was to study the retention properties of arsenate and phosphate at various

feed concentrations and to investigate the effect of pH on the rejection of these ions through modi?ed

polyacrylonitrile(PAN)ultra?ltration membrane.In one component solution with feed concentration of

10ppm arsenate and phosphate separately showed Z90%rejection at Z pH7with PAN UF as well as

nano?ltration membranes.Similarly,the mixture of arsenate and phosphate showed more than90%

rejection for feed concentration of100ppm each.However,the arsenate rejection decreased to55–60%

for10ppm arsenate and100ppm phosphate mixture in the feed,while phosphate rejection remained

Z90%.The rejection of arsenate and phosphate reversed to Z90%and$60%respectively for100ppm

arsenate and10ppm phosphate in the feed.The solution pH played an important role in changing the

membrane surface properties.The rejection coef?cient of arsenate and phosphate varied from5%to95%

by changing pH between3to10.Donnan steric-partitioning pore model incorporating dielectric

exclusion used to investigate the arsenate rejection and good agreement was found between experi-

mental and simulated data.

&2014Elsevier B.V.All rights reserved.

1.Introduction

In recent years,the removal of heavy metals and organic

pollutants from drinking water and wastewater stream is major

interest to environmental as well as process engineers.The

presence of heavy metal like arsenic compounds in water stream,

and eventually in potable water,is a serious environmental

problem[1].Generally,arsenic contamination in the water occurs

due to the natural phenomena such as the presence of arsenical

minerals,volcanic emissions;human activities like wood preser-

vatives,fertilizers,industrial processes and waste treatment.On

the other hand,the existence of large amount of phosphate in

domestic and industrial wastewater causes the eutrophication

which is a serious environmental issue in aquatic sources[2].

According to the World Health Organization(WHO)and US

Environmental Protection agency(EPA)guidelines,the permissible

limit for total arsenic and phosphate are0.01mg/l and0.1mg/l

respectively[3,4].The existing technique for separation of arsenic,

phosphate consists of either reduction and precipitation or ion

exchange or adsorption or electro-dialysis,and these traditional

technologies have two common disadvantages of high-energy

requirements and production of toxic sludge[5].Thus,removal

of arsenic and phosphate from water streams is very important

from both environmental and economic points of view.

Reverse osmosis(RO)and nano?ltration(NF)membranes were

used to separate the heavy metals and organic pollutants from

water and it consumes more energy i.e.high operating pressure

than UF and MF membranes.Generally,the predominant forms of

arsenic in water are arsenite(As-III)and arsenate(As-V)and the

pentavalent arsenic is thermodynamically stable and dominant in

oxygenated waters especially in the surface water.On the other

side,the phosphorus found in solutions includes orthophosphate,

polyphosphate,and organic phosphate[6].Brandhuber et al.[7]

examined the applicability of UF membrane,which consists of

sulfonic and carboxylic acid groups which exhibited72%of

arsenate rejection.It was also reported that ultra?ltration mem-

brane gave88%rejection of As-V due to Donnan principles which

were sensitive to membrane operating conditions[8].ZrO2UF

membrane was studied by Noordman et al.,which gave490%

rejection of phosphate ions[9].Some reports also showed arsenic

ions removal by ultra?ltration membranes which incorporated

coagulation agents or ionic ligands;however,these processes may

result in sludge formation[10,11].Furthermore,Ballet et al.[6]

show the ef?ciency of monovalent and divalent phosphate ions via

NF membrane and the rejection behavior was dependent on its

feed concentration,ionic strength,applied pressure and pH.Abidi

Contents lists available at ScienceDirect

journal homepage:https://www.wendangku.net/doc/198589093.html,/locate/memsci

Journal of Membrane Science

https://www.wendangku.net/doc/198589093.html,/10.1016/j.memsci.2014.05.040

0376-7388/&2014Elsevier B.V.All rights

reserved.

n Corresponding author.Tel.:t911126591005;fax:t911126582282.

E-mail address:gopal@dbeb.iitd.ac.in(G.P.Agarwal).

Journal of Membrane Science468(2014)11–19

et al.[12]studied the operating conditions for phosphate ions removal with NF membrane and they also reported more than93% of phosphate rejection at high pH.

Polyacrylonitrile(PAN)based ultra?ltration membrane is more advantageous because of high hydrophilicity and good solvent stability.Lohokare et al.[13]show that the surface hydrolysis of PAN UF membrane using NaOH by tangential mode led to reduc-tion in pore size due to conversion of NC to COO–on the membrane surface as well as pores.It was also reported that hydrolyzed PAN membrane gave more than90%rejection of arsenic[14].

Characterization and modeling of ionic solute transport through membranes are essential steps in the development and implementation of new membrane?ltration processes.From the literature,most of ionic transport models of membrane were based on Spiegler–Kedem(SK)model and Donnan steric pore model(DSPM)[15,16].The?rst was based on irreversible thermo-

dynamics,which considered the membrane as a black box where driving forces for solvent and solute?ux were related to concentration and pressure gradient[17].Later,DSPM model based on extended Nernst-Planck equation was?rst proposed by Bowen et al.[18]then,it was further improved by dielectric exclusion(DE)principle for counter ions effect on ionic solute rejection[19–21].

The aim of this work was to investigate the arsenate and phosphate ions rejection through novel polyacrylonitrile(PAN) based ultra?ltration(UF)membrane as a function of feed concen-tration and pH of the solution[22].The performance of modi?ed PAN UF membrane ionic rejection data was compared with nano?ltration membranes.DSPM-DE model was used to evaluate arsenate ion rejection as a function of?ux for modi?ed PAN UF membrane.

2.Materials and methodology

2.1.Materials

Required chemicals were of analytical grade and used without further puri?cation.Unmodi?ed polyacrylonitrile(PAN)mem-branes were procured from National Chemical Laboratory(NCL), Pune.Nano?ltration membranes NF200and NF99were procured from M/s.Permionics India Ltd.and M/s.Alfa Laval Corporation respectively.Sodium arsenate(Na2HAsO4á7H2O)was procured from Loba Chemie(India);sodium phosphate(Na2HPO4á7H2O) and methanesulfonic acid(CH4O3S)were obtained from Sigma chemicals(USA).Sodium hydroxide(1N NaOH)solution pur-chased from Merck(Germany).Deionized water with resistivity of0.055m S/cm was used in all experiments.

2.2.Experimental setup

A lab-scale plate and frame module(PLEIADE RAYFLOW s)had the effective membrane surface area of100cm2area procured from Orelis Environment SAS.The centrifugal pump was used to maintain the optimized cross?ow velocity of0.72m/s and transmembrane pressure of200kPa,which depends on pump speed and backpressure(Fig.1).All experiments were performed by total recycle mode and feed was maintained at ambient room temperature(27–301C).During the whole operation,the volu-metric?ux was determined for each samples.The pure water permeability of each membrane coupon was measured before and after completion of an experiment.The material balance of solute was carried out after completion of experiments to evaluate any absorption on the membrane.2.3.Characterization of membranes

The unmodi?ed polyacrylonitrile ultra?ltration membranes surface were modi?ed as per protocol described in earlier pub-lication[14].

2.3.1.Atomic force microscopy

Effective mean pore radius,porosity and pore size distribution of the membrane were measured by image surface analysis via atomic force microscope(AFM)made by Bruker,USA.ScanAsyst mode(peak force tapping mode:spring constant0.4N/m,reso-nant frequency40kHz)was used to analyze the samples.In addition,all samples were subjected with feed solution pH range of2–9.SPIP?(Image metrology)software(SPIP v6)used to calculate the number of pores through AFM images[23].Pore size distribution and effective mean pore radius of membrane were estimated by log normal distribution function(Eq.(1)),described by Bowen et al.[24]

f RerT?

1

r

?????????

2b

p expà

f loger=r nTtb=2g2

"#

e1Twhere

b?log1:0t

s n

r

2

"#

e1:1T

Hilal et al.[25]studied the AFM images to determine the surface porosity of the membrane.To obtain the reproducibility via AFM,all samples were scanned by the same frequency and the same surface area.

Porositye%T?

N?eπd2p=4T

image

?100%e2T

2.3.2.Tangential streaming potential

Electrokinetic properties such as iso-electric point(pI)and membrane charge density(X d)were calculated by tangential streaming potential(TSP).TSP measurements were made by using the SurPASS Electrokinetic Analyzer(Anton-Paar KG,Graz,Austria) equipped with adjustable clamping cell(distance of10075m m) which had sample surface area of25?55mm2.Background elec-trolyte of1mM KCl used to measure the zeta potential to evaluate the iso-electric point of PAN membrane at pH range of3–10. Fairbrother and Mastin(F–M)relationship(Eq.(3))was used to calculate zeta potential,because it eliminated the surface conduc-tance at low ionic strength[26].

ζ?ΔUΔ

p

?

η

ε?ε0?κe3

TFig.1.Schematic diagram of cross?ow PAN-UF membrane system.

M.R.Muthumareeswaran,G.P.Agarwal/Journal of Membrane Science468(2014)11–19 12

Gouy –Chapman relationship (Eq.(4))was used to determine the electrokinetic charge densities of different coupons of mod-i ?ed PAN UF membranes [27].

s e ?

2ελd k b T ze sinh ze

2k b T

e4Twhereas,the Debye length was calculated by λd ?

???????????????

?k b T

4e 2N a I

s e4:1T

In addition,the effective volumetric charge density (X d )was assumed to be uniformly distributed in cylindrical pores and the surface area of membrane.Therefore,the effective volumetric charge density was determined by using pore radius and electro-kinetic charge densities (Eq.(5))[27]X d ?

2s e Fr p

e5T

2.4.Arsenate,phosphate and sodium ion analysis

Feed,permeate and retentate samples of arsenate,phosphate and sodium were analyzed by Ion Chromatography (IC 3000)made by Dionex Ltd.,USA.Ion Pac As11HC column with 30mM NaOH solution was used to measure phosphate and arsenate ions with retention time of 5.1min and 6.6min respectively.CS12A column with 20mM methane sulfonic acid (MSA)used to measure sodium ion with the retention time of 4.3min.The rejection of arsenate,phosphate and sodium were calculated by the following equation:

R e%T?1àC p

C r

?100e6T

3.Results and discussion

3.1.Surface properties of PAN UF membrane

3.1.1.Water ?ux

Three different coupons of surface modi ?ed PAN UF membrane were used for the measurement of ?ux.The average volumetric water ?ux of modi ?ed PAN UF membrane was found to be 1.770.2?10à6m s à1at 100kPa and it was lesser than unmodi-?ed PAN membranes ?ux (1.4?10à5m s à1).The observed results indicated that all coupons of surface modi ?ed PAN UF membranes had the permeability of 2.370.2?10à11m s à1Pa à1.In addition,the nano ?ltration membranes (NF 200and NF 99)pure water permeabilities were found to be 7.970.3?10à12m s à1Pa à1and 1.870.2?10à11m s à1Pa à1respectively.

3.1.2.Pore size distribution

Modi ?ed PAN UF membrane pore size and its distribution was determined by AFM image analysis.The number of pores were arranged in ascending order by using median ranks [50%]as follows [28]:

χ?

k à0:3

m t0:4 ?100e7TThe obtained pore sizes were used in log normal distribution function (Eq.(1))to determine the effective mean pore radius along with standard geometrical deviation (i.e.pore size distribu-tion).In all cases,integration was performed by using the trapezium rule with a very narrow step size (0.03nm).Fig.2shows that the pore size distribution changed drastically with the function of pH.Moreover,the effective mean pore radius was found to be 0.9nm at pH Z 7.As shown in Table 1,pH Z 7,the

standard geometric deviation (s n )(or pore size distribution)was found to be less than 0.41?10à9m with a ?ux of r 0.19?10à5m s à1.Likewise,the volumetric ?ux (1.85?10à5m s à1)gradually increased along with pore size distribution (0.98?10à9m)by decreasing solution pH (up to pH 3).However,after pH 3the ?ux trend got reversed because of iso-electric point (pI)of the membrane i.e.,the membrane charge converted as negative to positive.In addition,the pH of solution also played an important role in image surface,which directly affected the membrane topography like roughness of the membrane surfaces.3.1.3.Membrane roughness

The surface roughness is also one of the important properties of the membrane and it depends on the scanning area,height between sample and cantilever [29].Each AFM image was ana-lyzed by scanning the area of 700?700nm 2and height range of 30.4nm of different portions of samples.The average roughness,root mean square roughness and average height were determined by AFM image analysis software.Fig.3shows topography of UF membrane as a function of pH of the solute.For pH 8,surface roughness (S q )was found to be 3.26?10à9m and it gradually decreased to 1.02?10à9m at pH 2(Table 1).From these results,it can be concluded that up to iso-electric point of membrane,the volumetric ?ux was directly proportional to the pore size distribu-tion and inversely proportional to the surface roughness of active layer.

3.2.Arsenate and phosphate ions rejection

3.2.1.Effect of feed concentration

The modi ?ed PAN membrane was analyzed for various feed concentrations of arsenate (100ppm,10ppm)and

phosphate

Fig.2.Effect of pH on pore size distribution (AFM distribution and theoretical distribution).

Table 1

Properties of modi ?ed PAN UF membrane as a function of pH.pH Roughness

(S q )

(?10à9m)Pore size

distribution (s n )(?10à9m)Δx =A k

(?10à5m)

Volumetric ?ux (J v )

(?10à5m/s)2 1.02 1.250.180.873 1.810.980.22 1.854 2.100.670.25 1.295 2.800.45 1.420.446 2.830.42 1.590.277 3.040.41 1.630.198

3.26

0.32

1.67

0.15

M.R.Muthumareeswaran,G.P.Agarwal /Journal of Membrane Science 468(2014)11–1913

(100ppm,10ppm)at optimized operating conditions and the results were shown in Fig.4.For multicomponent system,the equal feed concentrations (100ppm)of arsenate and phosphate ions rejection were found to be Z 95%.Moreover,sodium ion rejection was also found to be more than 95%to maintain the electroneutrality condition.However,the change in proportion of feed concentration in multicomponent system like 100ppm of arsenate along with 10ppm of phosphate resulted more than 95%of As (V)but PO 42àrejection coef ?cient reduced to 55%.In addition,as per Donnan equilibrium,the sodium ion rejection was also high (Z 90%)to maintain the charge balance of the components in the solution [13].Likewise,change in proportion of As (V)at 10ppm along with 100ppm of PO 42àgave lesser rejection of arsenate (57%)and higher rejection coef ?cient of phosphate (495%)with a sodium rejection of more than 90%.This behavior was due to ionic interaction between the solutes (electrostatic interaction),molar volume and interaction between ions and membrane charge [30].

3.2.2.Effect of pH

The modi ?ed PAN membrane was subjected with different pH conditions for arsenate and phosphate ionic rejection with opti-mized operating condition and the feed concentration of each ion as 10ppm.The variation in arsenate and phosphate along with sodium ion rejection was plotted as a function of pH as shown in Fig.5.For pH Z 7the arsenate and phosphate rejection was shown greater than 95%,whereas sodium ion was also found to be Z 95%following electroneutrality condition.In addition,the basic condi-tion,the membrane negative surface charge repulsed divalent anionic solutes such as arsenate and phosphate as per Donnan exclusion principle.For pH o 7,the rejection coef ?cient of arsenate and phosphate gradually reduced as low as 3%and 6%at pH 3.3.This behavior was due to properties of arsenate and phosphate ions,whereas monovalent arsenic eH 2AsO 4àTin the pH range p K a 1?2.2o pH o p K a 2?7.08;HAsO 42àin p K a 2?7.08o pH o p K a 3?11.5and H 2PO 4àin p K a 1?2.15o pH o p K a 2?7.20;HPO 42àdominates in p K a 2?7.20o pH o p K a 3?12.35[6,8].As shown in Fig.5,the iso-electric point (pI)of the membrane was found to be 3.2and the pI value also con ?rmed by zeta potential measurement via tangential streaming potential (TSP).Moreover,when pH moved to acidic range,the conversion of COO àto COOH on the membrane surface was enhanced.It reduced the effective negative charge density on membrane surface and thus also the capability of membrane to repel divalent anions to cause rejection by Donnan exclusion.Beyond the iso-electric point or pH o 3,

the

Fig.3.Topographic AFM images of modi ?ed PAN UF membrane studied at different

pH.

Fig.4.Arsenate and phosphate ion rejection as a function feed concentration at pH 7.0;cross ?ow velocity of 0.72m/s;transmembrane pressure 200kPa;ambient room

temperature.

Fig.5.Arsenate (10ppm)and phosphate (10ppm)along with sodium ion rejection as a function of different pH at cross ?ow velocity of 0.72m/s,transmembrane pressure 200kPa,ambient room temperature.

M.R.Muthumareeswaran,G.P.Agarwal /Journal of Membrane Science 468(2014)11–19

14

rejection coef ?cient of both ions was gradually increased up to 12%at pH 2.These observations indicated that below pI value,the positively charged surface membrane repulsed positively charged solute.

3.2.3.Effect of active layer thickness to membrane porosity (Δx/A k )

The membrane porosity was calculated by using Eq.(2).The ratio of active layer thickness to porosity of the membrane (Δx /A k )was estimated by using Hagen –Poiseuille equation (Eq.(A6))as shown in Appendix Section A.1.The Δx /A k changed with the pH of solution and it directly affected the ?ux along with rejection properties of ionic solutes.The variation of rejection coef ?cient and ?ux as a function of Δx /A k were plotted in Fig.6.It was observed that,at higher value of Δx /A k (1.6?10à5m)the rejec-tion coef ?cient of arsenate and phosphate was found to be Z 95%with a ?ux of 0.15?10à5m s à1.Moreover,rejection of arsenate and phosphate decreased to 3%along with increasing ?ux of 1.85?10à5m s à1at the value of (Δx /A k )0.22?10à5m.From these observations,it was found that volumetric ?ux was inversely proportional to active layer thickness to porosity of the membrane (Δx /A k )and to the rejection coef ?cient of ionic solutes.However,when Δx /A k was less than 0.22?10à5m,the rejection coef ?cient of ionic solutes was found to increase by 10%along with decreas-ing ?ux to 0.87?10à5m s à1.This behavior was due to isoelectric point of the membrane,which was located at lower pH region (i.e.below pI,the membrane surface charge converts as positive,as described earlier).

3.3.Ionic rejection through PAN UF and NF membrane

The surface modi ?ed PAN UF and NF membranes were used for arsenate and phosphate ion rejection by tangential mode and the results were plotted in Fig.7,as a function of time.The highest rejection of arsenate and phosphate (Z 90%)was obtained from PAN UF and NF 99membrane with a ?ux of 5.6?10à6m s à1and 4.8?10à6m s à1respectively.In addition,the anionic rejections were found to be 85%through NF 200membrane with a ?ux of 1.9?10à6m s à1.This was due to intrinsic membrane properties such as poor pore size distribution and surface charge density of NF 200(result not shown here).The observed results indicated that PAN UF membrane showed better performance as compared to NF membranes.

3.4.Modeling of arsenate and sodium ion rejection

The one-dimensional Donnan steric-partitioning pore model incorporated with dielectric exclusion (DSPM-DE)was used to evaluate arsenate along with sodium ion rejection as a function of ?ux.The DSPM-DE model was used for charged nano ?ltration membrane by Bowen et al.[16].The modeling of ionic transport in PAN UF membrane was derived with the following additional assumptions:(1)the dielectric constant of the solute within the pore and effective volumetric charge density across the pores were constant;(2)concentration polarization was negligible due to dilute feed solution (low feed concentration)and high cross ?ow velocity.The governing equations of DSPM-DE model shown in Appendix A and the nomenclature were shown in the list of symbols.

The effective volumetric charge density (X d )was calculated by electrokinetic charge density (s e )of the membrane via Fairbrother and Mastin (FM)function (Eq.(3))and Gouy Chapman relation (Eqs.(4)and (5)).Moreover,the volumetric charge density of membrane depends on feed concentration of the solute [31],thus,it was corrected by Freundlich isotherm.

j X d j ?q 12∑j z i j C 0

f s e8T

where q and s were the parameters of the isotherm and it was obtained by tangential streaming potential measurements.In addition,the volumetric charge density (X d )were used to evaluate dielectric constant of the solute within the pores (εp );this model,the dielectric exclusion was based on solvation energy barrier (Born model)[32].Moreover,the εp also calculated by using true rejection coef ?cient data with ?tting procedure [33].

The model calculation of arsenate rejection based on solute and membrane parameters listed in Table 2.The volumetric charge density (X d )and dielectric constant of solute within the pore (εp )were plotted as a function of feed concentration as shown in Fig.8.For low feed concentration,X d was found to be as low as à0.2mol m à3,whereas εp was calculated as 42.3.However,the X d values increased up to à46mol m à3while εp decreased to as low as 0.5with increased solute concentration (4mol m à3).These observed results showed that the dielectric constant of solute within the pore was dependent on feed concentration of solute and inversely proportion to effective volumetric charge density of membrane.This behavior occurred due to stronger interaction

of

Fig.6.Arsenate (10ppm)and phosphate (10ppm)ion rejection and ?ux (J v )as a function of active layer thickness to porosity of the membrane (Δx /A k )at cross ?ow velocity of 0.72m/s,transmembrane pressure 200kPa,ambient room

temperature.

https://www.wendangku.net/doc/198589093.html,parative study of NF and modi ?ed UF membrane for arsenate and phosphate rejections as a function of time [feed solution pH 7.0,cross ?ow velocity:0.72m/s,each ion feed concentration:50ppm,transmembrane pressure:250kPa,ambient room temperature].

M.R.Muthumareeswaran,G.P.Agarwal /Journal of Membrane Science 468(2014)11–1915

ions with water molecule,in the pores,at higher feed concentra-tion.This led to decrease the dielectric constant of solute within the pore(εp).Moreover,in this model theεp value was kept as constant as per the following equation[34]:

εp?5

8

εbe9T

Fig.9shows that the variation of arsenate ion rejection with respect to effective volumetric charge density of membrane.The model parameters ofΔx/A k(1.63?10à5m),effective mean pore radius r p(0.90?10à9m)and dielectric constant within the pore εp(48.9)were used to simulate the rejection data as a function of ?ux.When the X d had negative charge(Zà0.5mol mà3),the arsenate ion rejection was found to be more than90%which meant that the anionic solutes were repulsed at highly negative charge of membrane.However,the rejection coef?cient of ionic solutes was reduced as low as14%because of the negative charge density to become as positive(20mol mà3).This observation indicated that surface charge of the membrane played a signi?cant role on ionic transport through PAN UF membrane.

The comparison of experimental and simulated rejection data for different feed concentrations was plotted in Fig.10(a and b)as a function of?ux.In this simulation,optimized model parameters were same as per the previous calculation,while volumetric charge density wasà7.0mol mà3.As shown in Fig.10(a and b),the highest rejection of arsenate and sodium ions(Z90%)was obtained at low feed concentration(r1.4mol mà3);however,the rejections gradually reduced with increasing of feed concentration.A good agreement was found between simulated and experimental data;moreover,these comparative results indicated that DSPM-DE model could fully

predict the pattern of rejection as a function of?ux.However,the

higher feed concentration,the simulated ionic rejections were not

shown in good agreement with the experimental data(variation of

25%).It was due to the concentration polarization effect,which was

not taken in this study.Simulations were also performed to show the

validity of standard theory of ionic transport mechanism through

charged membrane in which dielectric exclusion was not taken.

Moreover,the simulated arsenate ionic rejection was reduced up to

70%and it did not correlate with the experiential results of low feed

concentration of0.14mol mà3,whereas,εp?εb(Fig.10a).This result concluded that dielectric exclusion was found to be important

property for modeling of ionic transport through charged PAN UF

membrane.Similarly,this model could be used for phosphate ion

transport through polyacrylonitrile ultra?ltration membrane.

4.Conclusions

Arsenate and phosphate ions separately showed effective

rejection(Z90%)for optimized operating parameters and for

concentration up to100ppm through surface modi?ed PAN UF

membrane.The rejection of these ions was also good(Z90%)for

the solution mixture provided the concentrations of As(V)and

PO42àwere equal in the feed.The experimental observation

Table2

Parameters for DSPM-DE model.

Parameters Values Assessment

T Temperature(K)298Fixed

D i;p Diffusivity(10à9m2sà1) 1.36/1.33Calculated by Wilke–Chang equation

HAsO2à

4

=Nat

r i;s Stoke radii of ions(?10à10m) 1.8/1.84Calculated

HAsO2à

4=Nat

εb Dielectric constant of water at251C78.4

L p Permeability of membrane(?10à11msà1Paà1)0.82Experimental

r p Mean pore radius(?10à9m)0.9Experimental

εp Dielectric constant of solution within the pores48.98Calculated

ΔW i Born solvation energy barrier 4.52Calculated

Adjustable parameters

X d Membrane volumetric charge density(mol mà3)Variable Experimentaltmodel

Δx=A k Ratio of membrane thickness to porosity(m)Variable Experimentalt

model

Fig.8.Effect on X d andεp as a function of feed

concentration.

Fig.9.Evaluation of arsenate ion rejection(for different volumetric charge density

(X d))as a function of J v at0.67mol mà3of feed concentration(simulated from

DSPM-DE model).

M.R.Muthumareeswaran,G.P.Agarwal/Journal of Membrane Science468(2014)11–19 16

showed that rejection coef ?cient of anionic solutes increased (Z 90%)with increasing pH of solute (Z pH 7),while volumetric ?ux was decreased.It was observed that modi ?ed PAN UF membrane gave higher rejection (Z 90%)of arsenate and phos-phate as compared to NF membranes at low operating pressure.

Donnan steric-partitioning pore model incorporated with dielectric exclusion (DSPM-DE)model successfully predicted the arsenate and sodium ion rejection.The higher rejection of arsenate was obtained with high negative charge density (X d )of modi ?ed PAN UF membrane.The concentration polarization was negligible at low feed concentration (r 100ppm).The comparison of simu-lated and experimental rejection data showed that DSPM-DE model fully predicted the tendencies of ionic rejection as a function of ?ux by proper choice of model parameters X d ,εp ,and Δx /A k .

Acknowledgments

We were greatly thankful to Dr.Ulhas Kharul,NCL Pune,India,

for supplying the PAN membrane used in this study and helpful

discussion on membrane properties.We would also thank Mr.Ankit Srivastava,research scholar,school of biological science,IIT Delhi,for the guidance to measure the AFM images.We would also acknowledge to Mr.Lukka Thuyavan and Mr.Satyendra Singh for their help in the experimental work.

Appendix A.Derivation of DSPM-DE model

The membrane pores were assumed cylindrical and ionic transport occurred due to convection,diffusion and electromigra-tion.In addition,equilibrium partitioning between the solute in the feed and membrane interface based on Donnan equilibrium,steric-partitioning and dielectric exclusion.The ionic transport within the membrane based on extension Nernst –Planck equation (Eq.(A1))is shown in Appendix Section A.1.The diffusion coef ?cient was corrected by hindrance factors (Eqs.(A8)and (A9))in terms of convective transport in extended Nernst –Planck equation.Moreover,hindrance factor of each solute was the function of λi which is the ratio between the solute radius and pore radius (Eq.(A7)).The electroneutrality within the membrane and permeability was maintained by Eqs.(A10)and (A11).The equilibrium partitioning between feed solution and membrane was based on Donnan equilibrium and dielectric exclusion as per Born effect as shown in Eqs.(A12)–(A16).Furthermore,the small variation of volumetric charge density did not affect the retention behavior of solutes,so it was assumed constant along the pore.The ionic transport within the system was de ?ned in Eqs.(A17)–(A20)(at x ?0,C 0i ;f |c i ;f e0Tand x ?Δx ,c i eΔx T|C i ;p :refers to feed/membrane interface and membrane/permeate interface respectively).For one-dimensional approach,radial effects were averaged and only concentration gradients along the membrane thickness was con-sidered.The concentration gradient was derived from the combi-nation of the ENP equation with the electro-neutrality condition (Eq.(A18)).The Runge –Kutta –Gill method was used to determine the concentration pro ?le along the pore (dc i ;f =dx )as the initial boundary condition of c i ;f e0T,whereas the concentration gradient (Eq.(A18))was integrated by across the active layer thickness (upper x ?Δx and lower x ?0)of the membrane.The iterations were performed many times until the convergence was obtained;that is the simulated permeate concentration did not vary from one iteration to another.Finally,the simulated rejection data was obtained from using Eq.(A.14).

A.1.Equations for DSPM-DE model

Basic equation:J i ?K i ;c c i V àK i ;d D i ;1dc i dx

àz i c i K i ;d D i ;1

F RT d ψd x eA1T

where J i ?VC i ;p eA2TD i ;p ?K i ;d D i ;1

eA3T

Wilke –Chang expression :

D i ;1?7:41?10à8

eφM T0:5

T

ηo eV m T"#

eA4T

Stokes –Einstein equation :r i ?

kT 6πηo D i ;1

eA5

https://www.wendangku.net/doc/198589093.html,parison of experimental (operating conditions:200kPa;pH-7.5;temp:27721C)and simulated rejection data (for different feed concentration)as a function of ?ux.(a)Arsenate ion rejection;(b)sodium ion along with As (V)rejection.

M.R.Muthumareeswaran,G.P.Agarwal /Journal of Membrane Science 468(2014)11–1917

Hagen–Poiseuille expression:

J v?V?ΔP e r2

p

A k

ηΔ?

?ΔPàΔπ r2p A k

ηΔeA6T

Hindrance factors:

λi?r i=r peA7T

K i;d?1:0à2:30λt1:154λ2t0:224λ3eA8T

K i;c?e2à?iTe1:0t0:054λà0:988λ2t0:441λ3TeA9TElectroneutrality condition:

∑n

i?1

z i c i;fexTtX d?0ewithin the membraneTeA10T

∑n i?1z i c i;fexT?∑

n

i?1

z i

dc i;f

dx

?0ein permeateTeA11T

Equilibrium partitioning:

c i;f i;f ?

γ

i;s

γ

i;p

?i expeàΔW iTexpàz i FΔψD

eA12T

where

?i?e1àλiT2eA13TEquilibrium partitioning between two ions:

c i;f

?0

i C0

i;f

!1=z

i

?

c j;f

?0

j

C0

j;f

!1=z

j

eA14T

where

?0

i ?

γi;s

γi;p?i expeàΔW iTeA15T

ΔW i?z2i e2

8πεo k B Tr s

1

εPà

1

εb

eA16T

Ionic transport: Inlet

z i c i;fe0Tt∑

n

i?1

j?2

z j?j'C j;f'c i;f

e0T

?0

i

C0

i;f

!z

j

=z i

2

4

3

5tX

d

?0eA17T

Transport within the pore

dc i;fexT

dx ?

V

D i;p

eK i;c c i;fexTàC i;pTà

z i c i;fexT

RT

F

dψ

dx

eA18T

dψexTdx ?

∑n

i?1

ez i V=D i;pTeK i;c c i;fexTàC i;pT

i?1i

c i;f

eA19T

Outlet

z i C i;pt∑

n

i?1

j?2

z j c jeΔxT

?0

j

c ieΔxT

?i'C i;p

àz

j

=z1

"#

?0eA20T

Rejection:

R i?1àC i;p

C0

i;f

eA21T

c i mole concentration of i th ion(mol mà3)

c i;f,c j;f concentration of I,j th ions within the pore

(mol mà3)

c i;fe0Tconcentration of i th ion at the inlet of the pore

(mol mà3)

c i;fexTionic concentration along the pore at x direction

(mol mà3)

c ieΔxT;c jeΔxTconcentration of I,j th ions at the membrane/

permeate interface(mol mà3)

C i;f concentration of i th ion in the bulk(mol mà3)

C0

i;f

,C0

j;f

concentration of I,j th ions in the wall(mol mà3)

C i;p;C j;p permeate concentration of I,j th ions(mol mà3)

C p total concentration in the permeate stream

(mol mà3)

C r total concentration in the retentate stream

(mol mà3)

d thickness of water/oriented solvent layer(m)

d2

p

mean diameter(m2)

D i;1molecular diffusion coef?cient of i th ion at in?nite

dilution(m2sà1)

D i;p pore diffusion coef?cient(m2sà1)

e electron charge(1.6023?10à19C)

f R theoretical probability density function(mà1)

f RerTtheoretical pores distribution(mà1)

f AFMerTAFM pores distribution(mà1)

F Faraday constant(C molà1)

I ionic strength(mol mà3)

J i ionic?ux of i th ion(mol mà2sà1)

J v total volume of permeate?ux(m2sà1)

k number of measured pores arranged in ascending

order(dimensionless)

k B Boltzmann constant(1.38?10à23J Kà1)

K i;c ionic hindrance factor for convection

(dimensionless)

K i;d ionic hindrance factor for diffusion(dimensionless)

L p membrane water permeability(m sà1Paà1)

m total number of measured pores(dimensionless)

M molecular weight of solvent(g molà1)

N number of pores

N a Avogadro number(molà1)

r pore radius(m)

r n average pore radius through AFM image(m)

r p effective mean pore radius(m)

r s Stoke radius(m)

R universal gas constant(J molà1Kà1)

R e experimental rejection percentage

R i theoretical rejection percentage

S q surface roughness(m)

T temperature(K)

V solvent velocity(m sà1)

V m molar volume at boiling point temperature(Lebas

method)(cm3molà1)

x axial direction at x coordinate

X d volumetric charge density of membrane(mol mà3)

z i;z j charge number of I,j th ions

Greek letters

ΔP e effective pressure difference(Pa)

ΔP applied pressure(Pa)

Δπosmotic pressure difference(Pa)

ΔU streaming potential(mV)

ΔW i solvation energy(dimensionless)

Δx membrane thickens(m)

Δψ

D

Donnan potential(dimensionless)

M.R.Muthumareeswaran,G.P.Agarwal/Journal of Membrane Science468(2014)11–19

18

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焊接图纸符号标注图解示例

一、焊接图纸符号标注图解示例 ★焊接符号标注实例及方法 在焊接结构图样上，焊接方法可按国家标准GB5185-85的规定用阿拉伯效字表示，标注在指引线的尾部。常用焊接方法代号见表3-9所示。如果是组合焊接方法，可用“/”分开，左侧表示正面(或盖面)的焊接方法，右侧表示背面(或打底)焊接方法。例如V形焊缝先采用钨极氢弧焊打底，后用手工电弧焊盖面，则表示为141/111。 焊缝符号和焊接方法代号标注示例见图3-21所示。该图表示V形坡口对接焊缝，背面封底焊，正面焊缝表面齐平，焊接方法为打底焊用手工钨极氮弧焊，盖面焊和封底焊用手工电弧焊。 二、焊接符号表示方法

1钢结构焊接符号含义大全 钢结构焊接符号也是依据GB324一1988《焊缝代号》来绘制。钢结构一般属于建筑学科，属于建筑行业。因此在钢结构焊接符号的标注中经常伴随有建筑符号、型钢符号、螺栓符号及铆钉符号等。 2钢结构焊缝符号表示的方法及有关规定： （1）焊缝的引出线是由箭头和两条基准线组成。其中一条为实线，另一条为虚线，线型均为细线。 （2）基准线的虚线可以画在基准线实线的上侧，也可画在下侧，基准线一般应与图样的标题栏平行，仅在特殊条件下才与标题栏垂直。 （3）若焊缝处在接头的箭头侧，则基本符号标注在基准线的实线侧;若焊缝处在接头的非箭头侧，则基本符号标注在基准线的虚线侧。 （4）当为双面对称焊缝时。基准线可不加虚线。 （5）箭头线相对焊缝的位置一般无特殊要求，但在标注单边形焊缝时箭头线要指向带有坡口一侧的工件。 （6）基本符号、补充符号与基准线相交或相切，与基准线重合的线段，用粗实线表示。 （7）焊缝的基本符号、辅助符号和补充符号(尾部符号除外)一律为粗实线，尺寸数字原则上亦为粗实线，尾部符号为细实线，尾部符号主要是标注焊接工艺、方法等内容。 （8）在同一图形上，当焊缝形式、断面尺寸和辅助要求均相同时，可只选择一处标注焊缝的符号和尺寸。并加注“相同焊缝的符号”，相同焊缝符号为3/4圆弧，画在引出线的转折处。 在同一图形上，有数种相同焊缝时，可将焊缝分类编号，标注在尾部符号内，分类编号采用A,B,C......在同一类焊缝中可选择一处标注代号。

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i -1的平方根 f(x) 函数f在自变量x处的值 sin(x) 在自变量x处的正弦函数值 exp(x) 在自变量x处的指数函数值，常被写作e x a^x a的x次方；有理数x由反函数定义 ln x exp x 的反函数 a x同 a^x log b a 以b为底a的对数； b log b a = a cos x 在自变量x处余弦函数的值 tan x 其值等于 sin x/cos x cot x 余切函数的值或 cos x/sin x sec x 正割含数的值，其值等于 1/cos x csc x 余割函数的值，其值等于 1/sin x asin x y，正弦函数反函数在x处的值，即 x = sin y acos x y，余弦函数反函数在x处的值，即 x = cos y atan x y，正切函数反函数在x处的值，即 x = tan y acot x y，余切函数反函数在x处的值，即 x = cot y asec x y，正割函数反函数在x处的值，即 x = sec y acsc x y，余割函数反函数在x处的值，即 x = csc y ζ角度的一个标准符号，不注明均指弧度，尤其用于表示atan x/y，当x、y、z用于表示空间中的点时 i, j, k 分别表示x、y、z方向上的单位向量 (a, b, c) 以a、b、c为元素的向量 (a, b) 以a、b为元素的向量 (a, b) a、b向量的点积 a?b a、b向量的点积 (a?b) a、b向量的点积 |v| 向量v的模 |x| 数x的绝对值 Σ 表示求和，通常是某项指数。下边界值写在其下部，上边界值写在其上部。 如j从1到100 的和可以表示成：。这表示1 + 2 + … + n M 表示一个矩阵或数列或其它 |v> 列向量，即元素被写成列或可被看成k×1阶矩阵的向量

CAD焊接图纸符号标注图解示例

CAD焊接图纸符号标注图解示例 焊接符号是一种工程语言，能简单、明了地在图纸上说明焊缝的形状、几何尺寸和焊接方法。下面小编就为大家介绍焊接图纸符号标注图解示例，一起来看看吧。 焊接符号是一种工程语言，能简单、明了地在图纸上说明焊缝的形状、几何尺寸和焊接方法。下面小编就为大家介绍焊接图纸符号标注图解示例，一起来看看吧。 一、焊接图纸符号标注图解示例 焊接符号标注实例及方法 在焊接结构图样上，焊接方法可按国家标准GB5185-85的规定用阿拉伯效字表示，标注在指引线的尾部。常用焊接方法代号见表3-9所示。如果是组合焊接方法，可用“/”分开，左侧表示正面(或盖面)的焊接方法，右侧表示背面(或打底)焊接方法。例如V形焊缝先采用钨极氢弧焊打底，后用手工电弧焊盖面，则表示为141/111。 焊缝符号和焊接方法代号标注示例见图3-21所示。该图表示V形坡口对接焊缝，背面封底焊，正面焊缝表面齐平，焊接方法为打底焊用手工钨极氮弧焊，盖面焊和封底焊用手工电弧焊。 二、焊接符号表示方法 钢结构焊接符号含义大全

钢结构焊接符号也是依据GB324一1988《焊缝代号》来绘制。钢结构一般属于建筑学科，属于建筑行业。因此在钢结构焊接符号的标注中经常伴随有建筑符号、型钢符号、螺栓符号及铆钉符号等。 钢结构焊缝符号表示的方法及有关规定： 1、焊缝的引出线是由箭头和两条基准线组成。其中一条为实线，另一条为虚线，线型均为细线。 2、基准线的虚线可以画在基准线实线的上侧，也可画在下侧，基准线一般应与图样的标题栏平行，仅在特殊条件下才与标题栏垂直。 3、若焊缝处在接头的箭头侧，则基本符号标注在基准线的实线侧;若焊缝处在接头的非箭头侧，则基本符号标注在基准线的虚线侧。 4、当为双面对称焊缝时。基准线可不加虚线。 5、箭头线相对焊缝的位置一般无特殊要求，但在标注单边形焊缝时箭头线要指向带有坡口一侧的工件。 6、基本符号、补充符号与基准线相交或相切，与基准线重合的线段，用粗实线表示。 7、焊缝的基本符号、辅助符号和补充符号(尾部符号除外)一律为粗实线，尺寸数字原则上亦为粗实线，尾部符号为细实线，尾部符号主要是标注焊接工艺、方法等内容。 8、在同一图形上，当焊缝形式、断面尺寸和辅助要求均相同时，可只选择一处标注焊缝的符号和尺寸。并加注“相同焊缝的符号”，相同焊缝符号为3/4圆弧，画在引出线的转折处。

钢筋图纸,符号,并注释含义

求，钢筋图纸，所以符号，并注释含义，谢谢。 如；KL5(2)200×500 , ?6@100/150 , 2?18;2?16 ,N2?12 含义为：面积为200×500的框架梁5号，两梁跨，梁上箍筋为6号，加密区为100mm非加密区为150mm,上层主筋为2根直径18mm，下层为2根直径16mm，腰筋（N）为2根直径12mm. 梁编号由梁类型代号、序号、跨数及有无悬挑代号几项组成，应符合表10-1的规定。 表10-1 梁类型代号序号跨数及是否带有悬挑 楼层框架梁KL XX (XX)或(XXA)或(XXB) 屋面框架梁WKL XX (XX)或(XXA)或(XXB) 框支梁KZL XX (XX)或(XXA)或(XXB) 非框架梁L XX (XX)或(XXA)或(XXB) 悬挑梁XL XX 注：(XXA)为一端有悬挑，(XXB) 为两端有悬挑，悬挑不计入跨数。 例：KL7(5A)表示第7号框架梁，5跨，一端有悬挑。 ⑶等截面梁的截面尺寸用b X h 表示；加腋梁用b X h YLt×ht表示，其中Lt为腋长，ht为腋高；悬挑梁根部和端部的高度不同时，用斜线“/ ”分隔根部与端部的高度值。 例：300×700 Y500×250表示加腋梁跨中截面为300×700，腋长为500，腋高为250； 200×500/300 表示悬挑梁的宽度为200，根部高度为500，端部高度为300。 ⑷箍筋加密区与非加密区的间距用斜线“/ ”分开，当梁箍筋为同一种间距时，则不需用斜线；箍筋肢数用括号括住的数字表示。 例：?8@100/200(4) 表示箍筋加密区间距为100，非加密区间距为200，均为四肢箍。 ⑸梁上部或下部纵向钢筋多于一排时，各排筋按从上往下的顺序用斜线“/ ”分开；同一排纵筋有两种直径时，则用加号“+”将两种直径的纵筋相连，注写时角部纵筋写在前面。 例：6?25 4/2 表示上一排纵筋为4?25，下一排纵筋为2?25； 2?25+2?22 表示有四根纵筋，2?25 放在角部，2?22放在中部。 ⑹梁中间支座两边的上部纵筋不同时，须在支座两边分别标注；支座两边的上部纵筋相同时，可仅在支座的一边标注。 ⑺梁跨中面筋（贯通筋、架立筋）的根数，应根据结构受力要求及箍筋肢数等构造要求而定，注写时，架立筋须写入括号内，以示与贯通筋的区别。 例：2?22+(2?12) 用于四肢箍，其中2?22为贯通筋，2?12为架立筋。 ⑻当梁的上、下部纵筋均为贯通筋时，可用“；”号将上部与下部的配筋值分隔开来标注。 例：3?22；3?20 表示梁采用贯通筋，上部为3?22，下部为3?20。 ⑼梁某跨侧面布有抗扭腰筋时，须在该跨适当位置标注抗扭腰筋的总配筋值，并在其前面加“*”号。例：在梁下部纵筋处另注写有*6?18 时，则表示该跨梁两侧各有3?18的抗扭腰筋。 ⑽附加箍筋（密箍）或吊筋直接画在平面图中的主梁上，配筋值原位标注。 ⑾多数梁的顶面标高相同时，可在图面统一注明，个别特殊的标高可在原位加注。 腰筋 腰筋又称“腹筋”分二种：一种为抗扭筋，在图纸上以N开头，一种为构造配筋以G开头。梁的抗扭它在设计上属构造配筋，即力学上不用设计计算具体力的大小，按国家设计规范的构造要求查得此数据。当梁高达到一定要求时，就得加设腰筋，按多少、加多大规格按构造要求规范查得。抗扭腰筋的锚固长度按规范或图集受力钢筋要求设置，构造配筋的锚固长度按12d且≥150mm要求设置。 当梁高超过450mm时，为防止由于温度变形及砼收缩等的原因在梁中部产生竖向裂缝，在梁的两侧沿高度每隔300~400mm，应设置一根直径不小于10mm的纵向构造钢筋。

图纸常用符号解释

钢筋平法图集常用符号解释 la：非抗震构件的钢筋锚固长度。 laE：抗震构件的钢筋锚固长度。 bw：剪力墙的厚度。 bf：转角处的暗柱的厚度。 ln：梁的净跨度。 llE：钢筋的搭接长度。 hc：支座的净宽度。 λv：为约束边缘构件的配筋特征值，计算配筋率时箍筋或拉筋抗拉强度设计值超过360N/mm2,应按360N/mm2计算；箍筋或拉筋沿竖向间距：一级不宜大于100mm， 二级不宜大于150mm。 bf：剪力墙厚度。 bc：端柱端头的宽度。 bw：剪力墙厚度。 lc：为约束边缘构件沿墙肢的长度，不应小于图集中表内的数值、1.5bw和450mm三者的最大值，有翼墙或端柱时尚不应小于翼墙厚度或端柱沿墙肢方向截面高度；加300mm。ln：梁跨度值。 lae：纵向受拉钢筋抗震锚固长度。 la：受拉钢筋最小锚固长度。 lle：纵向受拉钢筋抗震(绑扎)搭接长度。 ll：纵向受拉钢筋非抗震绑扎搭接长度。 lni：梁本跨的净跨值。 hac：暗柱长度。 Hn：所在楼层的柱净高。 hc：柱截面长边尺寸（圆柱为截面直径），也表示为端柱的宽度。 hw：抗震剪力墙墙肢的长度（也表示梁净高）。 hb：梁截面高度。 Ac：为计算边缘构件纵向构造钢筋的暗柱或端柱的截面面积。 各类结构构件名称代码1柱KZ-框架柱 KZZ-框支柱 XZ-芯柱 LZ-梁上柱 QZ-剪力墙上柱 2剪力墙（1）墙柱 YDZ-约束边缘端柱 YAZ-约束边缘暗柱 YYZ-约束边缘翼墙柱 YJZ-约束边缘转角柱 GDZ-构造边缘端柱 GAZ-构造边缘暗柱 GYZ-构造边缘翼墙柱 GJZ-构造边缘转角柱 AZ-非边缘暗柱 FBZ-扶壁柱

焊接图纸符号标注图解示例

焊接图纸符号标注图解示例 焊接图纸符号标注图解示例焊接符号是一种工程语言,能简单、明了地在图纸上说明焊缝的形状、几何尺寸和焊接方法。下面小编就为大家介绍焊接图纸符号标注图解示例,一起来看看吧。 一、焊接图纸符号标注图解示例 ★焊接符号标注实例及方法 在焊接结构图样上,焊接方法可按国家标准GB5185-85的规定用阿拉伯效字表示,标注在指引线的尾部。常用焊接方法代号见表3-9所示。如果是组合焊接方法,可用“/”分开,左侧表示正面(或盖面)的焊接方法,右侧表示背面(或打底)焊接方法。例如V形焊缝先采用钨极氢弧焊打底,后用手工电弧焊盖面,则表示为141/111。 焊缝符号和焊接方法代号标注示例见图3-21所示。该图表示V形坡口对接焊缝,背面封底焊,正面焊缝表面齐平,焊接方法为打底焊用手工钨极氮弧焊,盖面焊和封底焊用手工电弧焊。 二、焊接符号表示方法 1钢结构焊接符号含义大全 钢结构焊接符号也是依据GB324一1988《焊缝代号》来绘制。钢结构一般属于建筑学科,属于建筑行业。因此在钢结构焊接符号的标注中经常伴随有建筑符号、型钢符号、螺栓符号及铆钉符号等。 2钢结构焊缝符号表示的方法及有关规定: （1）焊缝的引出线是由箭头和两条基准线组成。其中一条为实线,另一条为虚线,线型均为细线。 （2）基准线的虚线可以画在基准线实线的上侧,也可画在下侧,基准线一般应与图样的标题栏平行,仅在特殊条件下才与标题栏垂直。 （3）若焊缝处在接头的箭头侧,则基本符号标注在基准线的实线侧;若焊缝处在接头的非箭头侧,则基本符号标注在基准线的虚线侧。 （4）当为双面对称焊缝时。基准线可不加虚线。 （5）箭头线相对焊缝的位置一般无特殊要求,但在标注单边形焊缝时箭头线要指向带有坡口一侧的工件。 （6）基本符号、补充符号与基准线相交或相切,与基准线重合的线段,用粗实线表示。

工程图学符号标注

直线度（－）——是限制实际直线对理想直线直与不直的一项指标。平面度——符号为一平行四边形，是限制实际平面对理想平面变动 量的一项指标。它是针对平面发生不平而提出的要求。 圆度（○）——是限制实际圆对理想圆变动量的一项指标。它是对具有圆柱面（包括圆锥面、球面）的零件，在一正截面（与轴线垂直 的面）内的圆形轮廓要求。 圆柱度（/○/）——是限制实际圆柱面对理想圆柱面变动量的一项指标。它控制了圆柱体横截面和轴截面内的各项形状误差，如圆度、 素线直线度、轴线直线度等。圆柱度是圆柱体各项形状误差的综合 指标。 线轮廓度（⌒）——是限制实际曲线对理想曲线变动量的一项指标。它是对非圆曲线的形状精度要求。 面轮廓度——符号是用一短线将线轮廓度的符号下面封闭，是限制 实际曲面对理想曲面变动量的一项指标。它是对曲面的形状精度要求。 定向公差——关联实际要素对基准在方向上允许的变动全量。 定向公差包括平行度、垂直度、倾斜度。

平行度（‖）——用来控制零件上被测要素（平面或直线）相对于基准要素（平面或直线）的方向偏离0°的要求，即要求被测要素对基准等距。 垂直度（⊥）——用来控制零件上被测要素（平面或直线）相对于基准要素（平面或直线）的方向偏离90°的要求，即要求被测要素对基准成90°。 倾斜度（∠）——用来控制零件上被测要素（平面或直线）相对于基准要素（平面或直线）的方向偏离某一给定角度（0°～90°）的程度，即要求被测要素对基准成一定角度（除90°外）。 定位公差——关联实际要素对基准在位置上允许的变动全量。 定位公差包括同轴度、对称度和位置度。 同轴度（◎）——用来控制理论上应该同轴的被测轴线与基准轴线的不同轴程度。 对称度——符号是中间一横长的三条横线，一般用来控制理论上要求共面的被测要素（中心平面、中心线或轴线）与基准要素（中心平面、中心线或轴线）的不重合程度。 位置度——符号是带互相垂直的两直线的圆，用来控制被测实际要素相对于其理想位置的变动量，其理想位置由基准和理论正确尺寸确定。

图纸内符号

主题：五金厂常用名词中英文对照 材料：MATERIAL 比例：SCALE 披锋：BURR 未注：UNSPECIFIED（UNLESS） 注释：NOTES 标准规格：SPECTION 绘制：DWD（DRAWN BY）厚度：TH（THICKNESS） 检查：CHK（CHECKED BY）公差：TOLERANCES 弯曲：BEND 设计：MODEL 表面处理：FINISH 处理：TREATMENT 单位：UNIT 锻烧：ANNEALING 客户：CUSTOMER 第三角法：THIRD ANGLE PROJECTION 通过：PASSED 第一角法：FIRST ANGLE PROJECTION 电解片：SECC 不锈钢：SUS STAINLESS STEEL 电解铁：GMS PLA TE 白口铁：STEEL PLATETIN 马口铁：STEEL PLATE LEAD 锌铁：SPGC CGAL V ANIZ STEEL 红铜：COPPER 铝合金：ALLOY 磷铜：PHBRONZE 青铜：BRONZE 白铁：SPTE（ELEOTROLYILC TIN COAED STEEL） 光泊：SPCC 锡：TIN 铅：LEAD 扁铁：CRS（COLD ROUED STEED） 铁枝：LRON 黄铜：BRASS SHEET 弹簧钢：SPRING STEEL 锑片：TERNE PLATE 铝片：ALUM（ALUMINUM）PLATE 压缩板：PRESS BOARD 白海棉：SPONGE 硬橡胶：HARD RUBBER 弹簧铜线：SWP 快巴：FIBRE SHEET 备注：REMARK 电镀：PLATED 氧化：ANODIZE 电叻：NI-PLATED 电彩锌：YELLOW CHROMATE 热处理：HT（HEAT TRANENT） 镀锌：ZINCING（GALV ANIZE）氧化黑（喷黑）：ANODIZE BLACK 最大：MAX 氧化白（喷白）：ANODIZE WHITE 最小：MIN 形状：SHARP 样办：SAMPLE 结果：RESULT 项目：POINT 电银：SILVER PLATE 攻牙（嗒牙）：TAP 光泽性：GLOSS 硬度：HEADNESS 条件：CONDITION 除油：FREE OF OIL 图纸认识 认识图纸内符号：

工厂图纸实际标注符号

工厂图纸实际标注符号 Company Document number：WTUT-WT88Y-W8BBGB-BWYTT-19998

sA 转换开关 SQ行程开关 QF断电器元件符号全注解: 电流表 PA 电压表 PV 有功电度表 PJ 无功电度表 PJR 频率表 PF 相位表 PPA 最大需量表(负荷监控仪) PM 功率因数表 PPF 有功功率表 PW 无功功率表 PR 无功电流表 PAR 声信号 HA 光信号 HS 指示灯 HL 红色灯 HR 绿色灯 HG 黄色灯 HY 蓝色灯 HB 白色灯 HW 连接片 XB 插头 XP 插座 XS 端子板 XT 电线,电缆,母线 W 直流母线 WB 插接式(馈电)母线WIB 电力分支线 WP 照明分支线 WL 应急照明分支线 WE 电力干线 WPM 照明干线 WLM 应急照明干线 WEM 滑触线 WT 合闸小母线 WCL 控制小母线 WC 信号小母线 WS 闪光小母线WF 事故音响小母线 WFS 预告音响小母线 WPS 电压小母线 WV 事故照明小母线 WELM 避雷器 F 熔断器 FU 快速熔断器 FTF 跌落式熔断器 FF 限压保护器件 FV 电容器 C 电力电容器 CE 正转按钮 SBF 反转按钮 SBR 停止按钮 SBS 紧急按钮SBE 试验按钮 SBT 复位按钮 SR 限位开关 SQ 接近开关 SQP 手动控制开关 SH 时间控制开关 SK 液位控制开关 SL 湿度控制开关 SM 压力控制开关 SP 速度控制开关 SS 温度控制开关,辅助开关 ST 电压表切换开关 SV 电流表切换开关 SA 整流器 U 可控硅整流器 UR 控制电路有电源的整流器 VC 变频器 UF 变流器 UC 逆变器 UI 电动机 M 异步电动机 MA 同步电动机 MS 直流电动机 MD 绕线转子感应电动机 MW 鼠笼型电动机 MC 电动阀YM 电磁阀 YV 防火阀 YF 排烟阀 YS 电磁锁 YL 跳闸线圈 YT 合闸线圈 YC 气动执行器 YPA,YA 电动执行器 YE 发热器件(电加热) FH 照明灯(发光器件) EL 空气调节器 EV 电加热器加热元件 EE 感应线圈,电抗器 L 励磁线圈 LF 消弧线圈 LA 滤波电容器 LL 电阻器,变阻器 R 电位器 RP 热敏电阻 RT 光敏电阻 RL 压敏电阻 RPS 接地电阻 RG 放电电阻 RD 启动变阻器 RS 频敏变阻器 RF 限流电阻器 RC 光电池,热电传感器 B 压力变换器 BP 温度变换器 BT 速度变换器 BV 时间测量传感器 BT1,BK 液位测量传感器 BL 温度测量传感器 BH,BM 序号元件名称新符号旧符号 1 继电器 K J 2 电流继电器 KA LJ 3 负序电流继电器 KAN FLJ 4 零序电流继电器 KAZ LLJ 5 电压继电器 KV YJ 6 正序电压继电器 KVP ZYJ 7 负序电压继电器 KVN FYJ 8 零序电压继电器 KVZ LYJ 9 时间继电器 KT SJ 10 功率继电器 KP GJ 11 差动继电器 KD CJ 12 信号继电器 KS XJ 13 信号冲击继电器 KAI XMJ 14 继电器 KC ZJ 15 热继电器 KR RJ 16 阻抗继电器 KI ZKJ 17 温度继电器 KTP WJ 18 瓦斯继电器 KG WSJ 19 合闸继电器 KCR或KON HJ 20 跳闸继电器 KTR TJ

图纸符号注释

1 153K 153 线接触器33 AHeK 辅助加热器接触器65 ATPN1 ATP 主电源断路器 1 2 155R 155 线继电器34 AHeKN 辅助加热器接触器断路器66 ATPPK ATP主电源接触器 3 156R 156 线继电器35 AHeS 辅助加热器开关67 ATPSTMN ATP STM 装置电源断路器 4 160SAR1, 2 1600㎞/h速度辅助继电器1，2 36 AHWN 自动洗手盆NFB 68 ATPVCN ATP 装置电压控制器断路器 5 30DLR 30㎞/h 门锁继电器37 AMLpR1～3 标志灯预留继电器 1～3 69 ATr 辅助变压器 6 30SR 30㎞/h 速度继电器38 AmpN1, 2 放大器断路器 1, 2 70 B运非R 制动控制手柄「运转-快速」定位继电器 7 33COR 关门压紧用速度条件断开继电器39 AOCN 交流电过流NFB 71 B1非R 制动控制手柄「1N-快速」定位继电器 8 5DLR 5㎞/h 门锁继电器40 APCR 空气管路关闭继电器72 B2非R 制动控制手柄「2N-快速」定位继电器 9 5SR 5㎞/h 速度继电器41 APCS 空气管路关闭开关73 B3非R 制动控制手柄「3N-快速」定位继电器 10 A5SR 5㎞/h 速度继电器辅助继电器42 APCV 空气管路关闭阀74 B4非R 制动控制手柄「4N-快速」定位继电器 11 70SR 70㎞/h 速度继电器43 APOR 空气管路开启继电器75 B5非R 制动控制手柄「5N-快速」定位继电器 12 ABHeCN 上水水泵加热器用断路器44 APOV 空气管路开启阀76 B6非R 制动控制手柄「6N-快速」定位继电器 13 ACK1 交流电接触器 1 45 APPS 空气管路压力开关77 B7非R 制动控制手柄「7N-快速」定位继电器 14 ACK1R 交流电接触器 1 继电器46 APU 辅助电源装置78 B非R 制动控制手柄「快速(运转-7N)」定位继电器 15 ACK2 交流电接触器 2 47 APUCN 辅助电源装置控制断路器79 B1～3K 制动控制手柄「1N-3N」定位接触器 16 ACK2R 交流电接触器 2 继电器48 APUBMN 辅助电源装置风机电机断路器80 B4～5K 制动控制手柄「4N-5N」定位接触器 17 ACLN 滤清器断路器49 Arf 辅助整流器81 B6～7K 制动控制手柄「6N-7N」定位接触器 18 ACM 辅助压缩电机50 ARfK 辅助整流器接触器82 B非K 制动控制手柄「非常」定位接触器 19 ACMGV 辅助压缩电机控制器51 ARfKR 辅助整流器接触器继电器83 Bat 蓄电池 20 ACMGVR1, 2 辅助压缩电机控制器继电器 1, 2 52 ARfN2 辅助整流器断路器 2 84 BatK1, 2 蓄电池接触器 1, 2 21 ACMHe 辅助压缩电机加热器53 ARfRN 辅助整流器接触器断路器85 BatK2R 蓄电池接触器 2 继电器 22 ACMK 辅助压缩电机接触器54 Arr 避雷器86 BatKCN 蓄电池接触器控制断路器 23 ACMN 辅助压缩电机断路器55 ASCN 激活的悬挂控制NFB 87 BatKN 蓄电池接触器断路器 24 ACMR1, 2 辅助压缩电机继电器 1, 2 56 ATCBR ATC 制动继电器88 BatN1, 2 蓄电池断路器 1, 2 25 ACMS 辅助压缩电机开关57 ATCKB1R ATP缓制动1继电器89 BatVDN 蓄电池电压检测断路器 26 ACOCR1, 2 交流电过流继电器 1, 2 58 ATCKB4R ATP缓制动4继电器90 BCCN 制动控制单元控制断路器 27 ACOCRR1, 2 交流电过流预留继电器 1, 2 59 ATN 辅助变压器断路器91 BCU 制动控制单元 28 ACOSN 电源诱导断路器60 ATPBTMN ATP BTM 装置电源断路器92 BCUHe 制动控制单元加热器 29 ACVN1, 2 转换电源断路器 1, 2 61 ATPCOR ATP 切断继电器93 BCUN 制动控制单元断路器 30 ADCD1, 2 自动门控设备 1, 2 62 ATPDMIN ATP DMI 装置电源断路器94 BKK 母线断开接触器 31 ADCOS11～12 自动门控设备切断开关 11～12 63 ATPDRUN ATP DRU 装置电源断路器95 BKKN 母线断开接触器用断路器 32 ADN1, 2 自动门控设备断路器 1, 2 64 ATPFN ATP 风扇电源断路器96 BKKONR 母线断开接触器闭合检测继电器

符号标注

第8章符号标注 标注是机械设计中非常重要的内容。 PCCAD2004系统根据机械制图要求，提供了丰富的、非常完善的标注功能，各种标注都与绘图比例自动建立了联系。本章介绍粗糙度、形位公差、基准符号、锥度/斜度、中心孔标注、圆孔标记、焊接符号等的使用方法。这些功能位于PCCAD2004下拉菜单的“符号标注”项，用户也可以通过工具条访问。 §8.1 粗糙度PC_CCD 粗糙度标注按机械制图国标设计。智能的粗糙度标注功能可以自动识别被 标注实体,标注方向可以在实体的法向改变，标注位置可以沿实体的切线方向拖动，当实体的切向在90-120、270-300度范围时，自动引出标注，如图8-1所示。粗糙度符号不仅支持“超级编辑”功能，而且可以使用AUTOCAD特有的“夹 执行： 1.键盘：PC_CCD（或CC） ?107?

2.菜单：PCCAD2004?符号标注?粗糙度 出现：对话框，如图8-2 图8-2 输入：粗糙度的标注形式、粗糙度值以及其他参数。设置了有关参数后点取图8-2中的“确定”按钮，切换到作图屏幕。 出现提示：请选择线、圆、圆弧： 输入： [1] 选到实体时：沿实体的法向或切向拖动符号，按下鼠标左键定位。 [2] 未选到实体时： 提示：选取标注标注表面的方向： 输入：输入角度值或拖动鼠标定向 提示：请指定标注位置： 输入：拖动鼠标确定位置。 结果：完成粗糙度标注。之后重复 ?108?

出现提示：请选择线、圆、弧： 输入：按“Esc”键或两次鼠标右键退出标注。 【注】⒈鼠标点取图8-2中的符号右边的图象按钮可以选择“加工纹理” 和“基本符号“等属性。 2. 选择“加工纹理“和”基本符号“时，从图8-2所示的对话框左 上角的预览区域可以很直观地看到所选择的效果。 3. 鼠标点取图8-2中的“设置(S)按钮。点取后出现对话框，如图 8-3。在此可以改变粗糙度符号的文字高度、颜色、线宽等属性。 图8-3 §8.2 形位公差PC_XWGC 标注形位公差。 执行： 1.键盘：PC_XWGC（或XW） 2.菜单：PCCAD2004?符号标注?形位公差 出现：对话框，如图8-4 ?109?

道理工程图例及符号..

十三章道理工程图例及符号 一、一般规定 1、图幅及图框尺寸应符合下表的规定： 图幅及图框尺寸(mm) 幅面格式 2、需要缩微后存档或复制的图纸，图框四边均应具有位于图幅长边、短边中点的对中标志(下图)，并应在下图框线的外侧,绘制一段长100mm标尺，其分格为10mm。对中标志的线宽宜采用大于或等于0.5mm、标尺线的线宽宜采用0.25mm的实线绘制(下图)。

对中标志及尺寸 二、图标及会签栏 1、图标应布置在图框内右下角(图)。图标外框线线宽宜为0.7mm；图标内分格线线宽宜0.25mm。 2、图标应采用下图所示中的一种。 图标 3、会签栏宜布置在图框外左下角(见下图)，并应按图绘制。会签栏外框线线宽宜为0.5mm；内分格线线宽宜为0.25mm。 会签栏（单位mm） 4、当图纸需要绘制角标时，应布置在图框内的右上角，角标线线宽宜为0.25mm。

角标（单位mm） 三、坐标 1、坐标网格应采用细实线绘制，南北方向轴线代号应为X；东西方向轴线代号应为Y。坐标网格也可采用十字线代替(下图a)。 坐标值的标注应靠近被标注点；书写方向应平行于网格或在网格延长线上。数值前应标注坐标轴线代号。当无坐标轴线代号时，图纸上应绘制指北标志(下图b) 坐标网格及标线 2、当坐标数值位数较多时，可将前面相同数字省略，但应在图纸中说明。坐标数值也可采用间隔标注。 3、当需要标注的控制坐标点不多时,宜采用引出线的形式标注。水平线上、下应分别标注X轴、Y轴的代号及数值(下图)。当需要标注的控制坐标点较多时，图纸上可仅标注点的代号，坐标数值可在适当位置列表示出。 坐标数值的计量单位应采用米，并精确至小数点后三位。

形状位置公差标注符号

标注符号 直线度（－）——是限制实际直线对理想直线直与不直的一项指标。 平面度——符号为一平行四边形，是限制实际平面对理想平面变动量的一项指标。它是针对平面发生不平而提出的要求。 圆度（○）——是限制实际圆对理想圆变动量的一项指标。它是对具有圆柱面（包括圆锥面、球面）的零件，在一正截面（与轴线垂直的面）内的圆形轮廓要求。 圆柱度（/○/）——是限制实际圆柱面对理想圆柱面变动量的一项指标。它控制了圆柱体横截面和轴截面内的各项形状误差，如圆度、素线直线度、轴线直线度等。圆柱度是圆柱体各项形状误差的综合指标。 线轮廓度（⌒）——是限制实际曲线对理想曲线变动量的一项指标。它是对非圆曲线的形状精度要求。面轮廓度——符号是用一短线将线轮廓度的符号下面封闭，是限制实际曲面对理想曲面变动量的一项指标。它是对曲面的形状精度要求。定向公差——关联实际要素对基准在方向上允许的变动全量。定向公差包括平行度、垂直度、倾斜度。 平行度（‖）——用来控制零件上被测要素（平面或直线）相对于基准要素（平面或直线）的方向偏离0°的要求，即要求被测要素对基准等距。 垂直度（⊥）——用来控制零件上被测要素（平面或直线）相对于基准要素（平面或直线）的方向偏离90°的要求，即要求被测要素对基准成90°。 倾斜度（∠）——用来控制零件上被测要素（平面或直线）相对于基准要素（平面或直线）的方向偏离某一给定角度（0°～90°）的程度，即要求被测要素对基准成一定角度（除90°外）。 定位公差——关联实际要素对基准在位置上允许的变动全量。定位公差包括同轴度、对称度和位置度。 同轴度（◎）——用来控制理论上应该同轴的被测轴线与基准轴线的不同轴程度。 对称度——符号是中间一横长的三条横线，一般用来控制理论上要求共面的被测要素（中心平面、中心线或轴线）与基准要素（中心平面、中心线或轴线）的不重合程度。 位置度——符号是带互相垂直的两直线的圆，用来控制被测实际要素相对于其理想位置的变动量，其理想位置由基准和理论正确尺寸确定。 跳动公差——关联实际要素绕基准轴线回转一周或连续回转时所允许的最大跳动量。 跳动公差包括圆跳动和全跳动。圆跳动——符号为一带箭头的斜线，圆跳动是被测实际要素绕基准轴线作无轴向移动、回转一周中，由位置固定的指示器在给定方向上测得的最大与最小读数之差。

焊接图纸符号解析【大全】

焊接图纸符号解析 内容来源网络，由“深圳机械展（11万㎡，1100多家展商，超10万观众）”收集整理！ 更多cnc加工中心、车铣磨钻床、线切割、数控刀具工具、工业机器人、非标自动化、数字化无人工厂、精密测量、3D打印、激光切割、钣金冲压折弯、精密零件加工等展示，就在深圳机械展. 基本坡口符号 坡口符（注：图中“破”应为“坡”）

焊接图纸符号标注图解示例焊接符号标注实例及方法

在焊接结构图样上，焊接方法可按国家标准GB5185-85的规定用阿拉伯效字表示，标注在指引线的尾部。常用焊接方法代号见表3-9所示。如果是组合焊接方法，可用“/”分开，左侧表示正面(或盖面)的焊接方法，右侧表示背面(或打底)焊接方法。例如V形焊缝先采用钨极氢弧焊打底，后用手工电弧焊盖面，则表示为141/111。 焊缝符号和焊接方法代号标注示例见图3-21所示。该图表示V形坡口对接焊缝，背面封底焊，正面焊缝表面齐平，焊接方法为打底焊用手工钨极氮弧焊，盖面焊和封底焊用手工电弧焊。 焊接方式代号

焊接符号表示方法钢结构焊接符号含义大全 钢结构焊接符号也是依据GB324一1988《焊缝代号》来绘制。钢结构一般属于建筑学科，属于建筑行业。因此在钢结构焊接符号的标注中经常伴随有建筑符号、型钢符号、螺栓符号及铆钉符号等。 钢结构焊缝符号表示的方法及有关规定1、焊缝的引出线是由箭头和两条基准线组成。其中一条为实线，另一条为虚线，线型均为细线。2、基准线的虚线可以画在基准线实线的上侧，也可画在下侧，基准线一般应与图样的标题栏平行，仅在特殊条件下才与标题栏垂直。3、若焊缝处在接头的箭头侧，则基本符号标注在基准线的实线侧;若焊缝处在接头的非箭头侧，则基本符号标注在基准线的虚线侧。4、当为双面对称焊缝时。基准线可不加虚线。5、箭头线相对焊缝的位置一般无特殊要求，但在标注单边形焊缝时箭头线要指向带有坡口一侧的工件。6、基本符号、补充符号与基准线相交或相切，与基准线重合的线段，用粗实线表示。7、焊缝的基本符号、辅助符号和补充符号(尾部符号除外)一律为粗实线，尺寸数字原则上亦为粗实线，尾部符号为细实线，尾部符号主要是标注焊接工艺、方法等内容。8、在同一图形上，当焊缝形式、断面尺寸和辅助要求均相同时，可只选择一处标注焊缝的符号和尺寸。并加注“相同焊缝的符号”，相同焊缝符号为3/4圆弧，画在引出线的转折处。在同一图形上，有数种相同焊缝时，可将焊缝分类编号，标注在尾部符号内，分类编号采用A,B,C......在同一类焊缝中可选择一处标注代号。9、熔透角焊缝的符号应按图1-38方式标注。熔透角焊缝的符号为涂黑的圆圈，画在引出线的转折处。10、用形中较长的角焊缝(如焊接实腹钢梁的翼缘焊缝)，可不用引出线标注，而直接在角焊缝旁标注焊缝尺寸值K。11、在连接长度内仅局部区段有焊缝时，按图1-40标注。K为角焊缝焊脚尺寸。12、当焊缝分布不规则时，在标注焊缝符号的同时。在焊缝处加中实线表示可见焊缝，或加栅线表示不可见焊缝。13、相互焊接的两个焊件，当为单面焊带双边不对称坡口焊缝时，引出线箭头指向较大坡口的焊件。14、环绕工作件周围的围焊缝符号用圆圈表示，画在引出线的转折处，并标注其焊角尺寸K。15、三个或三个以上的焊件相互焊接时，其焊缝不能作为双面焊缝标注，焊缝符号和尺寸应分别标注。16、在施工现场进行焊接的焊件其焊缝需标注“现场焊缝”符号。现场焊缝符号为涂黑的三角形旗号，绘在引出线的转折处。

施工图常用符号及图例大全

提示 一、定位轴线 1、作用 定位轴线是施工中墙身砌筑、柱梁浇筑、构件安装等定位、放线的依据。 规定：主要承重构件，应绘制水平和竖向定位轴线，并编注轴线号；对非承重墙或次要承重构件，编写附加定位轴线。 2、定位轴线的编号 1）横向定位轴线编号用阿拉伯数字，自左向右顺序编写； 2）纵向轴线编号用拉丁字母（除I、O、Z），自下而上顺序编写。 平面图上定位轴线的编号，宜标注在图样的下方与左侧。在两轴线之间，有的需要用附加轴线表示，附加轴线用分数编号。 3）对于详图上的轴线编号，若该详图同时适用多根定位轴线，则应同时注明各有关轴线的编号，如下图所示。

二、索引符号与详图符号 1）详细表示某些重要局部，需要另绘制其详图进行表达。 2）对需用详图表达部分应标注索引符号，并在所绘详图处标注详图符号。 三、标高符号 标高是标注建筑物高度方向的一种尺寸形式，以米为单位。 绝对标高：以青岛附近黄海平均海平面为零点测出的高度尺寸，它仅使用在建筑总平面图中。 相对标高: 以建筑物底层室内地面为零点测出的高度尺寸。 建筑标高: 指楼地面、屋面等装修完成后构件的表面的标高。如楼面、台阶顶面等标高。 结构标高: 指结构构件未经装修的表面的标高。如圈梁底面、梁顶面等标高。

四、引出线

五、其他符号 1、连接符号： 对于较长的构件，当其长度方向的形状相同或按一定规律变化时，可断开绘制，断开处应用连接符号表示。 连接符号为折断线(细实线)，并用大写拉丁字母表示连接编号。 2、折断符号 1）直线折断：当图形采用直线折断时，其折断符号为折断线，它经过被折断的图面。 2）曲线折断：对圆形构件的图形折断，其折断符号为曲线。

图纸符号注释

CAD快捷键 L, *LINE 直线 ML, *MLINE 多线（创建多条平行线） PL, *PLINE 多段线 PE, *PEDIT 编辑多段线 SPL, *SPLINE 样条曲线 SPE, *SPLINEDIT 编辑样条曲线 XL, *XLINE 构造线（创建无限长的线） A, *ARC 圆弧 C, *CIRCLE 圆 DO, *DONUT 圆环 EL, *ELLIPSE 椭圆 PO, *POINT 点 DCE, *DIMCENTER 中心标记 POL, *POL YGON 正多边形 REC, *RECTANG 矩形 REG, *REGION 面域 H, *BHATCH 图案填充 BH, *BHA TCH 图案填充 -H, *HATCH HE, *HATCHEDIT 图案填充...（修改一个图案或渐变填充）SO, *SOLID 二维填充（创建实体填充的三角形和四边形）*revcloud 修订云线 *ellipse 椭圆弧 DI, *DIST 距离 ME, *MEASURE 定距等分 DIV, *DIVIDE 定数等分 DT, *TEXT 单行文字 T, *MTEXT 多行文字 -T, *-MTEXT 多行文字（命令行输入） MT, *MTEXT 多行文字 ED, *DDEDIT 编辑文字、标注文字、属性定义和特征控制框ST, *STYLE 文字样式 B, *BLOCK 创建块... -B, *-BLOCK 创建块...（命令行输入） I, *INSERT 插入块 -I, *-INSERT 插入块（命令行输入） W, *WBLOCK “写块”对话框（将对象或块写入新图形文件）-W, *-WBLOCK 写块（命令行输入）

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