Selection principle
When selecting the model, the corrosion of the measured fluid medium to the metal of the diaphragm capsule should be considered,the material of the diaphragm capsule of the transmitter is ordinary stainless steel, 304 stainless steel, 316/316L stainless steel, tantalum and so on.If the measured medium is highly viscous,easily crystallized, and highly corrosive,an isolated type transmitter must be selected.
When selecting the model, the temperature of the measured medium should be considered. If the temperature is high enough to reach 200 ~400℃, the high temperature type should be selected.Otherwise, the silicone oil will produce vaporization expansion, which makes the measurement inaccurate.
The isolated type pressure transmitter is preferably threaded connection, which saves money and facilitates installation.
According to the design specifications, in the selection of engineering design, whether pneumatic or electric transmitters are used should be comprehensively considered and analyzed according to the specific conditions of the device because of their speciality.
In general, the following conditions are preferred for the selection of pneumatic transmitters:
※ The distance from the transmitter to the display adjustment unit is short, usually not more than 150 meters;
※ The process materials are flammable and explosive medium and the relative humidity is very large;
※ Requires occasions where the instrument investment is less and the response speed is not fast;
※ Generally, small and medium-sized enterprises require easy maintenance and economic and reliable;
※ In large installations based on electric meters, some on-site control loops are not require centralized operation of the central control room.
The following conditions are preferred for the selection of electric transmitters:
※ The distance between the transmitter and the display adjustment unit is more than 150 meters;
※ Large enterprises require central control with highly centralized management;
※ Set up the objects controlled and managed by DCS computer;
※ Requires occasions where has fast response, information processing and complex computing;
In practice, in modern production installations, they are mixed and selected according to their respective characteristics.
Selection of pressure transmitter
From a physical point of view,the pressure on any object includes both atmospheric pressure and the pressure of the measured medium (generally referred to as gauge pressure). The sum of the pressures of the two parts acting on the measured object is called the absolute pressure.
P absolute = P gauge + atmospheric pressure
The instrument for measuring absolute pressure is called the absolute pressure gauge.For ordinary industrial pressure gauges, the gauge pressure value is measured, that is, the pressure difference between absolute pressure and atmospheric pressure.When the absolute pressure is greater than the atmospheric pressure value, the measured gauge pressure value is positive value, which is called positive gauge pressure; when the absolute pressure is less than the atmospheric pressure value, the measured gauge pressure value is negative value, which is called negative gauge pressure,that is, vacuum degree.The instrument for measuring the vacuum degree is called the vacuum gauge.
(1) In order to ensure the accuracy of pressure measurement, the minimum pressure measurement value should be higher than 1/3 of the measurement range of the pressure gauge;
(2) For occasions requiring remote distance measurement or high measurement accuracy, pressure sensors or pressure transmitters should be selected;
(3) When the measurement accuracy requirement is not high, the resistance type or inductance type, Hall effect type remote pressure transmitter can be selected.
(4) The pneumatic base type pressure indicating regulator is suitable for local pressure indication and adjustment;
(5) Pressure transmitter and pressure switch should be reasonably selected according to the explosion-proof requirements of the installation site.
Selection of differential pressure transmitter
The differential pressure transmitter is selected according to the following points:
(1)Measuring range, accuracy and measurement function;
(2) The environment faced by the measuring instrument, such as the industrial environment of petrochemical industry, which has the existence of thermal (toxic) and explosive dangerous atmosphere and higher environmental temperature.
(3) Physicochemical properties and state of the measured medium, such as strong acid, strong alkali, viscous, easy solidification, crystallization and vaporization, etc.
(4) Changes in operating conditions, such as changes in medium temperature, pressure, and concentration. Sometimes changes in concentration and density of gas phase and liquid phase should be considered from the beginning to the normal production of the parameters.
(5) The structure, shape, size of the vessel ,equipment accessories in the vessel and all kinds of inlet and outlet pipes of the measured object shall be considered, such as towers, solution tanks, reactors, boiler steam drums, vertical tanks, spherical tanks, etc.;
(6) Other requirements, such as environmental protection and sanitation;
(7) There must be a unified consideration in the selection of engineering instruments, and it is required to reduce specifications and varieties as much as possible and reduce spare parts,in order to facilitate management;
(8) Actual process conditions
In summary, the selection of the transmitter is feasible in technology，reasonable in economy，and convenient in management.
</a> âAbsolutely,â Tuck says. âThatâs the reason why we voted him captain. I donât think any of our captains are âYes men,â but I just think âTrel, he can be a loose cannon sometimes. Heâs a guy that can be fiery, and you know itâs coming from the heart. You know thereâs no way it means he doesnât love you or the team.
</a> And integration into their search can be used in conjunction with their current voice-activated search, allowing users to use gestures to scroll up and down the research results, to get the next page of search results or even to click on a specific result. There is definitely lots of potential for Google to integrate hand gestures in search.
</a> âMr. Lhota has said he would want Ray Kelly to stay as police commissioner, even though Ray Kelly has been the architect of the overuse of stop-and-frisk that has had such a negative effect on the relationship between police and . . . many communities of color,â de Blasio said.
</a> U.S. sales advanced 1.7 percent to $7.925 billion while International sales improved 4.2 percent to $9.65 billion. Sales climbed 12.4 percent in Europe and 1 percent in Western Hemisphere, excluding U.S.
</a> Asked during a visit to the eastern Siberian town of Chita whether the affair would cast a shadow over a U.S.-Russia summit due in September in Moscow, Putin told reporters on Wednesday: "Bilateral relations, in my opinion, are far more important than squabbles about the activities of the secret services."
</a> Hurricane Sandy's devastating storm track is a rare one among hurricanes; a new statistical analysis estimates that the track of the storm â which took an unusual left-hand turn in the Atlantic before slamming into the East Coast â has an average probability of happening only once every 700 years.
</a> West Nile human cases have been reported in 18 Texas counties, from El Paso to Angelina in East Texas. In the Dallas-Fort Worth Metroplex, which was the nationwide epicenter of last yearâs West Nile outbreak, only 10 cases have been reported this summer, according to the Texas Department of State Health Services.
</a> But the adrenalin rush and excitement soon took over. Just before we went out we huddled up in a circle and motivated each other saying: “We’re here for a reason, we should really just embrace the moment. It’s a part of history.”
</a> The neighborhoodâs coolest cafe is year-old Jonah James. Label-hounds and stroller-pushers congregate over powerful espresso ($3) and massive grilled cheese sandwiches with caramelized onions ($9). For old-school realness, thereâs Cavallaro, which consistently serves some of Montrealâs best Italian-style coffee ($2.50) and heaping sandwiches like meatball, chicken and prosciutto ($6.50).
</a> He told the judge he aims to get his high school degree and study chemical engineering in college. He then looked straight at Portillo's daughters, seated in the front row, and told them he knows how much pain he has caused them.
</a> We drove on towards red mountains with knife-edge peaks and corrugated ridges. The remote oasis town of Tamerza is ringed by knobbly hills of pale terracotta, with wind-gouged hollows and gunnels, scrunched, crumpled, pleated and gathered. Almost on the border with Algeria, the tiny village of Midès is spectacularly perched on a precipitous outcrop, surrounded by narrow crumbling canyons. As the sun set, each fold in the mountain range turned a darker grey, and the strata in the gorge below glowed red and gold.
</a> In response to this, the Committee said that it accepts that binge drinking, and alcohol misuse in general, is a major problem, particularly among younger people. To this end, it ‘strongly supports' measures to tackle this, such as reducing the availability of low-cost alcohol products.
</a> I suppose if you’re in charge of a political party, picking relentlessly on a bogeyman feels like an effective tactic. It fills your backbenchers with the thrill of righteous ire, unites them against a common enemy, and gives them someone to moan about other than you.
</a> Christopher Kane's indulgent AW13 campaign saw the revival of a serious gothic aesthetic. Velvet separates and dresses sauntered down the runway in rich navy and burgundy hues, perfect for the cold winter months. It would seem that the celebrity fash pack have already been adopting the vampish trend, take Alexa Chung in Christopher Kane at yesterday's Vogue dinner as a prime example.
</a> Genital cutting is often assumed to be a manifestation of patriarchal control over women, suggesting that men would be strong supporters of the practice. In fact, a similar level of support for stopping FGM/C is found among both women and men. In Chad, Guinea and Sierra Leone, substantially more men than women want FGM/C to end.
</a> For instance, on April 18, United Airlines increased its fee for changing a reservation from $150 to $200. Like lemmings, American, Delta Air Lines and US Airways all matched the higher fee within two weeks. Even JetBlue Airways — which has largely resisted char fees — increased its change fee by 50 percent.
</a> Two individuals privy to details of the discussions betweenthe two companies, however, described the talks as being intheir final stage. They said the two companies are trying towork out certain remaining kinks in the pending contract forSamsung SDI to provide battery technology for the Model X, amore affordable electric car model Tesla is expected to add toits product offerings in 2014.
</a> Current treatment involves a combination of antipsychotic drugs, psychological therapies and social support. But many patients do not respond to the initial medicines prescribed by their doctor, putting them at risk of further psychotic episodes and deteriorating mental health.
</a> Officials for the NFA were not immediately reachable for comment. A party source said the alliance was scheduled to meet on Sunday to discuss its next move, potentially even looking at pulling out of the GNC. The NFA, which has just under 40 seats, has already boycotted sessions in the past.
</a> With Harvey now electing to initially forego Tommy John surgery in favor of a natural healing process, straight up rehabilitation, the plot is taking a radical twist. Mystique is being injected into his brand.
</a> Keith Alexander, the NSA director, jousted with hecklers at the Black Hat security conference in Las Vegas on Wednesday as he defended the U.S. spy agency's surveillance programs before a crowd of cybersecurity experts and hackers.
</a> A United Nations inspection team was in Damascus on Thursday to investigate three sites of earlier alleged chemical attacks, and Secretary of State John Kerry wants that team to have access to the site of Wednesday's alleged attack, Psaki said.
</a> Standing tackles are far more sensitive this year and have the ability to make comfortable matches increasingly difficult with the accumulation of soft yellow cards. Be sure to make an attempt for possession only when your controlled player can see the ball, as FIFA 14’s physical base is likely to cause a reaction if you crunch through an unsuspecting individual.
</a> Senior U.S. defense officials said they remained confidentthat the United States was already well protected againstpossible missile attacks from North Korea by the two existingmissile interceptor sites, one in California and that in Alaska,where the Pentagon plans to add 14 more interceptors by 2017.
</a> Prosecutors have attempted to portray Zimmerman as a vigilante who profiled the unarmed teenager, while the defense says Martin attacked the former neighborhood watch volunteer, and that there is not enough evidence to prove otherwise.
</a> "Based on 16S surveys we know they're out there, but we don't know much about them -- that's why we call them microbial dark matter," Woyke added. "Using modern single-cell techniques allowed us to access the genetic make-up for some of them, even without growing them in the lab."
</a> Western nations believe Iran's uranium enrichment program ismeant to achieve a nuclear arms capability. Tehran denies this,saying it wants only to generate electricity and carry outmedical research. (Reporting by Patricia Zengerle; Editing by Bill Trott)
</a> The company, which touts the Z30 as its "biggest, fastestand most advanced smartphone" to date, said the device willbegin to hit store shelves in the UK and parts of the MiddleEast as early as next week.
</a> According to the Elias Sports Bureau, five of those nine home runs have been go-ahead shots, two more than anybody during that span. To put that in perspective, in the regular season since 2011, Young has only six go-ahead homers, and 116 players have more homers overall.
</a> In anticipation of the event, NYCHA sent crews Friday to tidy up the project before the candidates arrived, and tenants said they hadnât seen that many police officers assigned to overnight duty in Lincoln in years.
</a> Last week, turnover on the Hong Kong exchange hit its lowest weekly level this year, while in South Korea the weekly volume of foreign trading for the most liquid 3-year treasury futures in Korea .VMF.KTB -- a proxy for the regional local currency bond market -- is near its lowest point this year.
</a> A spokesman for United Airlines explained to the Daily News that none of those tickets were actually purchased. They were only reserved, and will not be honored unless customers have enough miles in their account.
</a> Visitors with bags of energy climb 377 steps to reach the pedestal of Lady Liberty. The less ambitious meanwhile can take a lift and save themselves for the 146-step climb to the top of the crown via a spiral staircase, where they are treated to far-reaching views of the city.
</a> HICKS: Yes, it was organized but also very disorganized for the police and army who were in there trying to figure out what was going on. They were moving around in these big open areas, where there’s a lot of places for people to hide. There’s a casino. There’s a movie theater, a huge supermarket. And so, there’s lots — all these shops, at any given place, someone could be there. So, this is what made it so difficult for them as they were trying to both locate the assailants and also to try to aid civilians to get out of the mall.
</a> Vietnam War veteran Mike Bowen, 65, will complete a 58,282-mile run Friday to commemorate each and every American soldier killed or missing in action during the bloody conflict, carrying a POW/MIA flag with him.
</a> In the September filing, FX Concepts reported that itsassets under management were $661.2 million from 20 accounts andit had 32 employees. In two weeks, it lost at least $40 millionand laid off 12 more people.
</a> Charged with first-degree murder are Chancey Allen Luna, 16, and James Francis Edwards Jr., 15, according to the Stephens County District Attorney's office. Michael Dewayne Jones, 17, who allegedly drove the vehicle carrying the other suspects, was charged with use of a vehicle in the discharge of a weapon and accessory to murder after the fact, the office said.
</a> Hun Sen, 60, has a reputation as a tough and wily survivor, starting with his defection from the Khmer Rouge to Vietnam, which after invading to oust the radical regime installed him first as foreign minister and later as prime minister.
</a> The State Department issued a major warning last year informing American diplomatic facilities across the Muslim world about potential violence connected to the anniversary of the Sept. 11 terrorist attacks.
</a> Such a coalition was indeed long inconceivable for theGreens, who entered parliament in the 1980s with flower pots andjeans pursuing an anti-nuclear, left-wing agenda. SFor theirpart, Merkel's Christian Democratic Union (CDU) had onceportrayed the Greens as dangerous radicals.
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</a> Federal Reserve Chairman Ben Bernanke said in July that the central bank needed to keep its bond buying in place given low inflation and an unemployment rate that may be overstating the health of the labor market.
</a> Yet under pressure from the highly vocal and important hunting lobby, the Maltese government has sought, since 2004, an exclusion from legislation that bans hunting of declining species. What seems most striking is the frame of argument used to justify the killing of protected species: the Maltese government argued that the turtle dove, while it may be in plight locally, had large (and, it should be added, largely unknown) numbers in countries such as Russia and Turkey. At a global level, therefore, this rendered it a species of least concern. In 2009 the argument was rejected and Malta judged in breach of international legislation by the European Court.
</a> Obviously, the right answer is whatever the parent feels is correct. Still, it can take awhile to come up with your own right answer. So for parents who would like some guidance, here are the allowance-related questions you're probably asking yourself – and some possible answers.
</a> LOS ANGELES, Sept 29 - Following are the top 10 movies atNorth American box offices for the three days starting Sept. 27,led by "Cloudy With a Chance of Meatballs 2" according to studioestimates compiled by Reuters.1 (*) Cloudy With a Chance of Meatballs 2 $ 35.0 million2 (1) Prisoners...........................$ 11.3 million3 (*) Rush................................$ 10.3 million4 (*) Baggage Claim.......................$ 9.3 million5 (*) Don Jon.............................$ 9.0 million6 (2) Insidious: Chapter 2................$ 6.7 million7 (3) The Family..........................$ 3.7 million8 (4) Instructions Not Included...........$ 3.4 million9 (6) We're the Millers...................$ 2.9 million10 (7) Lee Daniels' The Butler.............$ 2.4 million(*) = new releaseCUMULATIVE TOTALS:We're The Millers..............................$ 142.4 millionLee Daniels' The Butler........................$ 110.3 millionInsidious: Chapter 2...........................$ 69.5 millionPrisoners......................................$ 39.0 millionInstructions Not Included .....................$ 38.6 millionCloudy With a Chance of Meatballs 2............$ 35.0 millionThe Family.....................................$ 31.7 millionRush...........................................$ 10.6 millionBaggage Claim..................................$ 9.3 millionDon Jon........................................$ 9.0 million "Cloudy with a Chance of Meatballs 2" was released by SonyCorp's movie studio. "Rush" was released by Universal Pictures, a unit of ComcastCorp."Prisoners" and "We're the Millers" were distributed by WarnerBros., a unit of Time Warner Inc. Privately heldFilmDistrict released "Insidious: Chapter 2." "Don Jon" and "TheFamily" were distributed by privately held Relativity Media. "Baggage Claim" was released by Fox Searchlight, a unit of 21stCentury Fox."The Butler" is distributed by the privately held Weinstein Co. "Instructions Not Included" is distributed by Pantelion, a jointventure of Hollywood studio Lionsgate Entertainment andMexican media giant Televisa.
</a> Under the terms of the deal, Kwiatkowski will plead guilty to seven counts each of tampering with a consumer product and obtaining controlled substances by fraud. A change of plea hearing was scheduled for Wednesday.
</a> Analysts said that millions of Time Warner Cable subscribers in New York, Los Angeles and Dallas could be withoutCBS Corp programming for several weeks as the companiesappear no closer to settling a fee dispute.
</a> is erroneous. The bill does not concern converting “standard guns” into semi-automatics (a very unlikely scenario). It concerns converting standard capacity magazines into high capacity magazines.
</a> Writers and stars get flabby. Series start repeating themselves or go off the rails — such as Showtime’s “Dexter,” which probably should have cut its own throat a few seasons ago, or HBO’s “True Blood,” which is meeting its true death next summer.
</a> Many banks admit they are not cutting branches as quickly asthey should, wary of putting off clients just as bank earningsare recovering, and fearful of a public or political backlash incountries like Britain, where some of the biggest lenders wererescued by the taxpayer.
</a> West Texas Sour at Midland fell about 40 centsearlier in the day to trade at $3.65 a dollar under benchmarkfuture but later rose to $3.25 a barrel, closing the spread withMidland sweet to $1.25 a barrel.
</a> Setting the greenback on a slippery slope was a Wall StreetJournal report that the Fed may debate changing its forwardguidance to help hammer home its message that it will keep rateslow for a long time to come, traders said.
</a> "From what I found out, this is the same judge who scored the fight for Timothy Bradley over Manny Pacquiao. The Nevada State Athletic Commission is the best commission in the world, and if they feel it is right for the lady to judge, then that is fine by me. Things happen."
</a> The Giants know they would be better off using a high draft pick to fill the holes around Manning so they can make another championship run. So Coughlin is right when he says Eli Manning is âthe guyâ â both the man of the moment and the man of the future.
</a> * Online brokerage firm Charles Schwab Corp showedcustomers on its trading platform incorrect prices on certainfixed-income securities for about a week, the latest financialfirm to suffer from technology glitches. ()
</a> The most Emmy nominations, 17, went to 'American Horror Story: Asylum.' Close behind was 'Game of Thrones' with 16 nods, while "Saturday Night Live" and the Liberace biopic 'Behind the Candelabra' earned 15 nominations each, including nods for stars Michael Douglas and Matt Damon.
</a> Gold extended a rebound to a second day after breakingthrough a key technical level and as China inflation databoosted its appeal as a hedge against rising prices in theworld's second-biggest buyer of the metal.