screw air compressor technical training: ComVac exhibition

screw air compressor technical training: ComVac exhibition: hello Everybody! We already back office now after the ComVac exhibition! Mr Farzad came to our booth ,and discuss the diesel portable a...

ComVac exhibition

hello Everybody!

We already back office now after the ComVac exhibition!

Mr Farzad came to our booth ,and discuss the diesel portable air compressor!

Elena came to our booth room!

Zaltan Kocezian came to our booth room!

Francisco came to the booth room !we chat on the linked in before.we invited him came here!

friend from Net therland !

Two Stage Screw Air Compressor

Two stage air compressors work in a very similar manner with the primary difference being that they compress the air in 2 steps or stages. During the first step or stage, air is drawn in and compressed to an intermediate pressure. After being compressed in the first stage, the air is piped, usually through an intercooler where the air is allowed to cool, to be compressed in the final or second stage. Two stage compressors are normally good for pressures up to 200psi. Two stage pumps are more efficient at higher pressures because the air is cooled between the stages.

DCFM, SCFM and ACFM

            Displaced CFM (DCFM) is a mathematical formula that calculates the bore, stroke and rpm into a CFM figure(Bore x stroke x rpm/2200=DCFM). This figure will always be the highest CFM because this formula does not take into account variables like temperature, atmospheric pressure, humidity, friction and heat dissipation.

Another CFM term often used is Standard CFM (SCFM).  It defined as the measured flow of free air and converted to a standard set of reference conditions (14.5 PSIA, 68 Degrees F, and 0% relative humidity).

Yet another CFM term is Actual CFM (ACFM). AFCM can be determined in a number of different ways. The most common methods include measuring the volume of air that is moved through an orphic plate or measuring pump up times on large compressor tanks and running through a simple calculation. This CFM number takes in effect all the variables and will give the true output of the pump at the current working conditions (i.e. temperature, altitude, humidity, …).

Often times, CFM numbers are also shown at various pressures.  These numbers can be very useful to help determine if a compressor produces enough CFM for the desired application, but can be confusing when comparing differing pressures or volumes or different compressors.

The best way of comparing compressors is through SCFM. Since all the measurements are calculated back to a set of reference standard conditions, it levels the playing field among the multitude of different manufacturers.

Electric Motors and Horsepower

         Compressors are often rated by Horsepower(HP). As simple as this sounds, there are different variations of HP.  Some compressor manufacturers rate their air compressors by peak horsepower, also known as brake horsepower. Peak horsepower is the maximum output that a motor can produce while the motor has the start windings engaged. Peak HP can be as much as 5-7 times the rated or running HP. Under normal operating conditions, the start windings are only engaged for a small fraction of a second. Therefore, using peak horsepower as a comparison tool can be somewhat misleading since under normal operating conditions the motor only develops this horsepower during startup.  If  a motor drive system causes the start winding to remain engaged for a long period of time, the motor will either overheat if it has thermal protection or fail prematurely.

Most electric motor manufacturers rate their motors by the horsepower developed after the motor has come up to its designed operating rpm’s and disengaged the start windings. This is often referred to as running or rated horsepower and is a true indication of the HP a motor can sustain over a long period of time.

Some other factors to consider when looking at motors is Duty Cycle and Service Factor.  Duty cycle is normally rated as either intermittent or continuous and is defined as the time rating under full load.   In other words can the motor run at full load horsepower continuously or only intermittently. The other of the two noteworthy factors is the Service Factor (S.F.) rating of the motor. It is defined as the percentage of rated horsepower at which the motor can safely operate (i.e. 1.15 SF = 115% of rated HP).  Higher service factors allow motors to handle more varied conditions without causing motor overheating or premature motor failure.  Examples that could cause a motor to run within its Service Factor could be caused by low voltage, higher ambient temperatures, higher startup load …etc.

Shanghai Honest Compressor co.,Ltd 
www.osg-china.com/ 
TEL:+86-21-69177185 
FAX：+86-21-69177182 
Phone:+86 18916970085 
Mail/Skype:honestcompressor@126.com

www.screwtypeaircompressors.com

screw air compressor technical training: Shanghai Honest Compressor Co., Ltd PTC Exibition ...

screw air compressor technical training: Shanghai Honest Compressor Co., Ltd PTC Exibition ...: Shanghai Honest Compressor Co., Ltd., founded in early 2004, is a British-owned enterprise. The company, located in East industrial park of...

Shanghai Honest Compressor Co., Ltd PTC Exibition No.N1,E5-2 of 2015

Shanghai Honest Compressor Co., Ltd., founded in early 2004, is a British-owned enterprise. The company, located in East industrial park of Nanxiang Town, Jiading District, Shanghai, is a large-scale manufacturing enterprise specialized in the twin screw type air compressor and also important supplier of air system solutions.

OSG implements strict and full management in the whole process of production and strictly controls the product quality and environmental protection. The company has passed ISO9001: 2008 quality management system certification and national industrial product manufacture licensing certificate.

As to the technology research and development, the company pays more attention to market trend, is close to the user demand, actively absorbs the domestic and foreign brand performance structure advantages and integrates maintenance facilities which makes the air compressor more perfect structure, more excellent performance and obvious energy saving. Through the test of state compressor test center, energy consumption data is better than the national standard of energy saving and could supply multiple models and types of air-cooled, water-cooled screw air compressor ---5KW-400KW and 0.5m3/min–70m3/min flow of EU-EX series for the users to choose, supply inverter air compressor, oil-free compressor, mobile compressor and a full set of construction plans for the air compression station. The company has the capability of design and manufacture, user training, service support, overhaul and complete set of services. In order to contact the customers, we have opened service hotline for free---400-705-9168 and established branches and dealer sales and service teams in major cities to meet the various needs of users.

In the process of making the world first-class brand of the compressor, OSG takes the spirit of enterprise---technology, service and sincere to return customers as win-win goal.

PTC Exibition No.N1,E5-2 of 2015

screw air compressor technical training: screw air compressor technical training from shang...

screw air compressor technical training: screw air compressor technical training from shang...: Screw air compressor of the basic structure, working principle and composition Gong Yi write screw compressor is by the Swedish royal insti...

The working principle of the double screw air compressor

Screw refrigeration compressor screw refrigeration compressor is with spiral groove of one or two rotor (screw) in rotation in the air cylinder to gas compression refrigeration compressor. The work volume of the screw refrigeration compressor is rotary movement of the volume type compressor, according to the number of different screw rotor, the screw compressor with double screw and single screw two.

 一： screw compressor working process

一, working principle and working process 

1. The screw refrigeration compressor is mainly composed of rotor, chassis (including central suction, exhaust at the ends of the cylinder block and block, etc.), bearings, shaft seal, balance of piston and capacity adjusting device. Figure 3-1 is a typical open a pair of screw compressor rotor, on both ends of the cylinder and the end of the shape of the graph.

1 - suction side 2 - Yin rotor 3 - cylinder 4 - valve 5 - exhaust side 6 - Yang rotor

2. The working principle of the screw compressor's job is to rely on meshing movement with a male rotor with a female rotor, surrounded by and with the aid of the pair of the rotor of the casing wall around the space. 

3. The working process of the figure 3-2 for screw compressor working process diagram. Among them, the top view of a and b are a pair of rotor, c, d, e, f for a pair of rotor looked up from the bottom up.

 

Second, the characteristics in terms of the principle of the compressed gas, screw refrigeration compressor and reciprocating piston compressor, both belong to the volumetric compression machinery, in terms of its movement form, screw type compressor rotor with centrifugal compressor rotor, high-speed rotary motion. So has the characteristics of both screw refrigeration compressor. 1. The advantages

1) higher speed, and quality of light, small volume, cover an area of an area small, and a series of advantages. 

(2) dynamic balance performance is good, so the foundation can be very small. 

(3) simple and compact structure, less wearing parts, maintenance is simple, reliable use, to achieve automatic operation.

 (4) is not sensitive to liquid impact, single stage pressure ratio is high.

 (5) capacity is almost not affected by the influence of the exhaust pressure. In the wider range of conditions, can still keep high efficiency

2. The defects

 (1) large noise.

(2) requires special equipment and tools for processing of rotor. (3) large auxiliary equipment.      

The structure and basic parameters of the second quarter

  

A, the structure of the main components

The main screw refrigeration compressor parts, including casing, rotor, bearing, balance piston and shaft seal and capacity control device, etc.  

1. The chassis

The screw refrigeration compressor casing is usually split. It is composed of the body (cylinder block), suction side, exhaust side and end cover on both ends, as shown in figure 3-3.

 

 

1 - suction end cover

2 - suction side

3 - the body

4 - exhaust side

5 - exhaust end cove

2. The rotor

Is a major part of the screw refrigeration compressor rotor. As shown in figure 3-4, often adopts integral structure, make the screw on the shaft

1 - Yin screw 2, Yang screw (3) bearing and hydraulic balance piston screw refrigeration compressor is a high-speed overloading. In order to ensure accurate positioning of the rotor of the Yin and Yang and balance the axial force and radial force, must choose high precision, high speed and overloaded bearings and the corresponding balance mechanism, ensure the rotor reliable operation. Generally said, low load, small machine, using rolling bearing; High load, large and medium-sized machine, we adopt sliding bearing. In order to balance some or all of the axial force, usually with a balance piston to achieve this goal. As shown in figure 3-5 for a hydraulic balance piston structure. 4. Refrigeration system is very important for the seal of the shaft sealing, so in open overhung rotor shaft of the screw refrigeration compressor, usually adopt sealed performance is good contact type mechanical seal, it is mainly shown in figure 3-6 spring loaded and shown in figure 3 to 7 bellows type two kinds.

 

1, 2 - drive pin

3 - transmission set

The spring seat 4 -

5 - spring

6 - ring auxiliary seal ring

7 - ring

8 - card ring

9 - static ring

10 - static ring auxiliary seal ring

11 - stop pin

5. Capacity regulating valve Capacity regulating valve is used to adjust the screw refrigeration compressor capacity of a structure element, although there are many types of screw refrigeration compressor capacity adjustment method, but the slide valve adjusting method obtained widespread application. As shown in figure 3-8 a.

 

1 - lock nut

2, sealing gasket

3 - screw

4, drive set

5 - bellows

6 - ring

7 - static ring auxiliary seal ring

8 - static ring

9 - stop pin

A) valve working schematic diagram b) valve structure diagram 1, Yang rotor

2 - Yin rotor

3 - slide valve

4, hydraulic piston

6. Injection structure of screw refrigeration compressor are mostly adopt injection structure. As shown in figure 3-8 b.

7. Coupling

Open the screw refrigeration compressor by coupling and motor. 2, 1. The basic parameters of rotor tooth profile: driving rotor and driven the tooth surface of the rotor are profile, is the space curved surface.

Open the screw refrigeration compressor by coupling and motor.  

2, 1. The basic parameters of rotor tooth

Profile: active driven rotor and rotor tooth surfaces are profile, is the space curved surface.  

A) symmetric circular arc tooth profile b) asymmetric arc tooth profile

Tooth: type surface on the perpendicular to the axis of the rotor plane (face) projection is called the rotor tooth shape, is a plane curve.  

Meshing line: Yin and Yang rotor tooth meshing movement of mesh point on the surface of the platforms, trajectory, called tooth meshing line, as shown in figure

3-9, general by a circular arc tooth profile, cycloid, elliptic, parabolic and radial line, etc.  

Lines: the tooth profile curve of rotor is called lines.  

(1) the basic requirement of tooth shape

 

1) good air tightness Leaking ways as shown in figure 3-10. The direction of the contact wire leakage as shown in figure 3 to 11. As shown in figure 3-12, called leakage triangle.

 

2) the contact line length of short 3) as far as possible the larger area of utilization coefficient. (2) typical tooth In the screw compressor, for the same on both sides of the center line of the tooth shape contour line according to symmetrical line (FIG. 3-9 a), according to different asymmetric lines (FIG. 3-9 b), tooth profile are pitch outside or inside of the pitch circle type according to the single line (FIG. 3-9), otherwise known as bilateral lines. 1) X X tooth shape of tooth profile as shown in figure 3-13, it is composed of Atlas copco company of Sweden in arc cycloid unilateral asymmetric tooth shape on the basis of improvement. 2) the Sigma Sigma tooth shape of tooth profile as shown in figure 3 to 14, it is composed of German Kaeser compressor company in arc cycloid unilateral asymmetric tooth shape on the basis of successful development.

 

3) CF tooth profile CF tooth shape as shown in figure 3 to 15, which is designed by German GHH company.

Should see, in order to evaluate or comparing different tooth profile of a number of factors are mutually restricted. Such as: in order to reduce leakage triangle, ensure the screw's axial air tightness using point meshing cycloid, will inevitably increase the contact line length; In order to protect the occurrence of cycloidal point, use small circular arc or straight line type line addendum, then increase the leak triangles, and so on. So should be used according to different occasions to choose different tooth profile. Now all kinds of new tooth profile emerge in endlessly, such as Japan's Hitachi a tooth shape, of kobe b tooth shape (FIG. 3-16 a), Sweden, darfur (Stals) tooth shape (FIG. 3-16 b), greatly improve the performance of the screw compressor.