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Liquid level glasses,

type LLG 185 - 1550

REFRIGERATION AND

AIR CONDITIONING Technical leaet

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RD6DB30 to DKRCI.PD.GG0.A1.0 / 50H0855 Danoss A/S (AC-DSL / rz), 04 - 007

Technical leaet Liquid level glasses, type LLG 185 - 1550

Introduction

Features

LLG are liquid level glasses in ductile steel whichmeets the strictest requirements on industrialand marine rerigeration installations. The liquidlevel glasses are oered in 3 dierent versions:

with welding nipples (LLG)

with stop valves equipped with caps (LLG S)

with stop valves and sight adapter in acrylicglass ready or insulation on site (LLG SF).

The range o liquid level glasses is based on3 basic liquid level glasses: LLG 185, LLG 335and LLG 740. The other standard lengths arecombined by using variations o basic glasslengths.

LLG produce sucient ow areas to securethe highest possible degree o synchronousoperation, and have a specially hardenedreection glass or quick reading. The ront andthe base rame are mounted together rom the

ront with countersunk allen screws. This ensureseasy insulation on site as well as easy inspectionand service, i any.

All liquid level glasses are equipped as standardwith a built-in saety system (non return device). Ia glass is damaged, the pressure o the rerigerantwill activate the saety system and rerigerant losswill be limited to an absolute minimum.

RerigerantsApplicable to all common non ammablererigerants including R717 and non corrosivegases/liquids dependent on sealing materialcompatibility

Temperature range10/+100C (14/+1F) or50/+30C (58/+86F)

Maximum operating pressure: 5 bar g(363 psi g)

Equipped with boron silicate glass, hardenedby an accurately controlled heat treatmentprocess

Classifcation: To get an updated list ocertifcation on the products please contactyour local Danoss Sales Company

Design GlassLLG's are equipped with a boronsilicate glass,hardened by an accurately controlled heattreatment process. All glasses are according toDIN 7081.

GasketsThe glasses are equipped with a special non-asbestos carbon compound gasket whichprovides superior mechanical characteristics anda long time guarantee against service leakage.

ConnectorsLLG 590, LLG 995, LLG 1145 and LLG 1550 are

joined together by basic LLGs by means o aconnector. The connector holds the two basicglasses together by means o screws and guidingpins, which ensures a rigid construction.

Stop Valves/NipplesThe glasses are connected to the rerigerationsystem by means o welding nipples or stopvalves. Which ever system is used, the nipples orstop valves are screwed into a ange, which islocated in the correct position and subsequentlytightened with a seal gasket and 4 screws.

InstallationInstall the glasses on a bracket using the 4 screwssupplied with the glass.

Use the threaded holes on the back o therame to mount the glass on a bracket (not oDanoss supply). Always connect the pipingater mounting on the bracket. Please note theimportance o a minimum o stress in the liquidlevel glasses rom the connected pipes.Please also make sure that there is sucient spacebehind the the liquid level glasses to ensureproper insulation, service and inspection, etc.

For installations below 10C (+14F) it isrecommended to add the sight adapter to enablereading ater insulation has been applied.For installations below 10C (+14F) in R717plants it is recommended to use an oil column asdescribed in the ollowing pages. There will be noormation o bubbles or ice build-up in oilflledliquid level glasses, which may be the case in thererigerant-flled glasses.

The liquid sight glasses are designed towithstand high internal pressures. However, thepiping system in general should be designed toavoid liquid traps and reduce the risk o hydraulicpressure caused by thermal expansion.

Note:The LLG liquid level glass can only beplaced in CE approved applications withthe stop valves in ront.

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Danoss A/S (AC-DSL / rz), 04 - 007 RD6DB30 to DKRCI.PD.GG0.A1.0 / 50H0855 3


Technical data RerigerantsThe liquid level glasses are applicable toall common non ammable rerigerantsincluding R717 and non corrosive gases/liquids dependent on sealing material

compatibility.For urther inormation please see installationinstruction or LLG.Flammable hydrocarbons are notrecommended. For urther inormation pleasecontact your local Danoss Sales Company.

Temperature rangeThe liquid level glasses are applicable to theabove mentioned rerigerants within thetemperature range o:10/+100C (+14/+1F) or the LLG typeswith saety system with welding nipples andthe LLG S types with saety system with stopvalves.50/+30C (58/+86F) or the LLG SF types

with saety system with stop valves and sightadapter (acrylic glass) and the LLG F typeswith saety system and sight adapter (acrylicglass).

Pressure rangeAll LLG types are designed or:Max. operating pressure 5 bar g (363 psi g)Strength test: 50 bar g (75 psi g)Leakage test: at 5 bar g (363 psi g).

Example 1Rerigerant: R717 (ammonia).

Temperature: Recommended or temperaturesbelow 10C (+14F).

The principle shown in fg. 1 can be used inconnection with low temperature liquidseparators or intermediate coolers when thererigerant is R717 (ammonia).

As the liquid level in the R717 separator varies theoil level will change simultaneously.

Oil ChargingThe system is charged with synthetic oil typeSHC 6 with a specifc weight, diering romthat o R717, and (h) must be multiplied byapproximately 1.35 (the ratio o density oil todensity R717) to calculate H.

Charge the oil vessel (volume approximate 10litres) to a level just below the lower balancingpipe (A) through the oil charging valve. Close theoil charging valve.

The oil will show in the liquid level glass at a levelequal to the level in the oil vessel. When R717 isflled into the separator or intermediate coolerit will enter the oil vessel and press down the oilsurace.

The R717 will also rise into the upper balancepipe (B) to a level equal to the level in theseparator or intermediate cooler. As the oil

surace in the oil vessel is pressed down, the oilwill rise into the liquid level glass.

Note:It is important to use an oil which is not likely tomix with R717. The oil must have a high viscosityindex to ensure easy owing at low temperatures.Mobil SHC 6 o the synthetic polyalphaolefntype has proven suitable or this purpose.

Frostproof liquid level glasses

Fig. 1

Separator/Intermediate cooler

Purgevalve

Oil chargingvalve

Oil vessel

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4 RD6DB30 to DKRCI.PD.GG0.A1.0 / 50H0855 Danoss A/S (AC-DSL / rz), 04 - 007


Example 2Rerigerant: R717 (ammonia).

Temperature: Recommended or temperaturesbelow 10C (+14F).

Fig. shows a rostproo liquid level glass oran R717 liquid separator which is placed aboveground level. The arrangement is called aHampsonmeter.

Due to the evaporation taking place in theuninsulated balance pipe (ND 80/3 in.) thepressure in this pipe will be equal toP1 = P0 + H g.

P0 Separator pressure ....................................... N/m

H R717 liquid level (see fg. ) .............................. m R717 density ..................................................kg/m3

g Acceleration due to gravity 9.81 ...............m/s

Oil ChargingThe pressure will act on the oil surace in the oilvessel and cause the oil to rise in the liquid levelglasses which are installed in a length o e.g. in.pipe, the top o which is connected to the top othe separator which is at pressure P0.

The oil will rise to a level h and H can then becalculated by multiplying h by 1.35 (the ratio odensity oil to density R717).

Charge the oil vessel through the oil charging

valve to a level o approximately o ull level.The level will show in the lower liquid level glass.

Take care that the volume o the oil vessel issucient to allow the oil to rise into the liquidlevel glasses. When the system is operating keepthe bypass valve closed.

Note:It is important to use an oil not l ikely to mix withR717, and having a high viscosity index to ensureeasy oil movements at low temperatures. MobilSHC 6 o the synthetic polyalphaolefn type hasproven suitable or this purpose.

Frostproo liquid levelglasses

Fig. 2

Separatorpressure P0

Uninsulated

Bypass

Purgevalve

Oil chargingvalve

Oil vessel

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Material specifcation

No. Part Material DIN ISO ASTM

1 Front rame Steel RSt. 37., 17 100 Fe 360 B, 630 Grade C, A 83

Back rame Steel RSt. 37., 17 100 Fe 360 B, 630 Grade C, A 83

3 Sight glass Glass

4 Gasket Non-asbestos

5 Protective coating or sight

glass

Non-asbestos

6 Sight adapter PMMA-acrylic

8 Connecting piece Steel RSt. 37., 17 100 Fe 360 B, 630 Grade C, A 83

10 O-ring Cloroprene (Neoprene)

14 Flange Steel RSt. 37., 17 100 Fe 360 B, 630 Grade C, A 83

15 Balls Stainless steel

18 Welding nipple Steel RSt. 37., 17 100 Fe 360 B, 630 Grade C, A 83

19 Stop valve (SNV-ST*) Steel

LLG S and LLG SFLLG

* See technical data or SNV-ST valves.

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Dimensions and weights

* Only or LLG SF with sight adapter.

1) Type LLG) Type LLG S and LLG SF

Type A B C D Weight

LLG 185 - 1550

LLG 185mm

in.

185

7

55

10

69

48

4. kg 1)

5.8 kg )

LLG 335mm

in.

335

13

405

16

63

1/

4

1

7.5 kg 1)

9. kg )

LLG 590mm

in.

590

3

660

6

69 + 63

+

48 + 4

+ 1

13. kg 1)

15.1 kg )

LLG 740*mm

in.

740

9

810

3

63

4

1

16.5 kg 1)

18.5 kg )

LLG 995mm

in.

995

39

1065

4

69 + 63

+

48 + 4

+ 1

.5 kg 1)

4.7 kg )

LLG 1145mm

in.

1145

45

115

47

63

4 + 4

1 + 1

5.7 kg 1)

8.0 kg )

LLG 1550mm

in.

1550

61

160

63

63

4

1

33.5 kg 1)

36.1 kg )

LLG

LLG S and LLG SF

Specifed weights are approximate values only.

* please note that LLG 740 consist o one back piece and ront sight glasses.

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Ordering How to orderThe table below is used to identiy liquid levelglasses required.

Please note that the type codes only serve to

identiy the liquid level glasses, some o whichmay not orm part o the standard product range.

For urther inormation please contact your localDanoss Sales Company.

Type codesExample for type codes

LLG 740 SF Valve type LLG Liquid Level Glass

Nominal size in mm Combined by:

185 DN 185

335 DN 335

590 DN 590 LLG 185 + LLG 335

740 DN 740 1 Back piece and ront pieces995 DN 995 LLG 185 + LLG 740

1145 DN 1145 LLG 335 + LLG 740

1550 DN 1550 LLG 740 + LLG 740

Equipment - Saety system and welding nipples

F Saety system and sight adapter

S Saety system and stop valves (SNV-ST)

SF Saety system, stop valves (SNV-ST) and sight adapter

Important!Where products need to be certifed accordingto specifc certifcation societies or where higherpressures are required, the relevant inormationshould be included at the time o order.

Liquid level glasses - LLG

With safety system and welding nipples

LengthType Code no.

mm in.

185 7 LLG 185 2512+049

335 13 LLG 335 2512+050

590 3 LLG 590 2512+051

740 9 LLG 740 2512+052

995 39 LLG 995 2512+053

1145 45 LLG 1145 2512+054

1550 61 LLG 1550 2512+055

Liquid level glasses or insulating - LLG F

With safety system and sight adapter

LengthType Code no.

mm in.

185 7 LLG 185 F 2512+078

335 13 LLG 335 F 2512+079

590 3 LLG 590 F 2512+080

740 9 LLG 740 F 2512+081

995 39 LLG 995 F 2512+082

1145 45 LLG 1145 F 2512+083

1550 61 LLG 1550 F 2512+084

Liquid level glasses - LLG S

With safety system and stop valves (SNV-ST)

LengthType Code no.

mm in.

185 7 LLG 185 S 2512+056

335 13 LLG 335 S 2512+057

590 3 LLG 590 S 2512+058

740 9 LLG 740 S 2512+059

995 39 LLG 995 S 2512+060

1145 45 LLG 1145 S 2512+061

1550 61 LLG 1550 S 2512+062

Liquid level glasses or insulating - LLG SF

With safety system, stop valves (SNV-ST)and sight adapter

LengthType Code no.

mm in.

185 7 LLG 185 SF 2512+066

335 13 LLG 335 SF 2512+067

590 3 LLG 590 SF 2512+068

740 9 LLG 740 SF 2512+069

995 39 LLG 995 SF 2512+070

1145 45 LLG 1145 SF 2512+071

1550 61 LLG 1550 SF 2512+072

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