Home > Accessories > Flow Meter > Roots Meter

Roots Meter

DATE:2014-01-13 | comments: | posted by:liuailin


For almost a century, Roots meters have been used for billing of commercial and industrial gas loads. Accuracy, dependability, and low maintenance are key factors in custody transfer measurement applications. The time-proven Roots meter is the preferred flow meter in the distribution, transmission and production segments of the natural gas industry for accurate measurement of gas from the well to the burner.

Roots flow meter LLQ series of Kingnor is a flow meter for volumetric gas volume and flow measurement. It is designed for noncorrosive gases like natural gas, inert gases, air, coal gas, and man others.

The gas must be dry and filtered. The meter is used for high-accuracy applications and measurements where a wide rangeability is required.The LLQ can be used for legal measurement. The meter is conform to many national and international guidelines for flow meters.

Our factory process all the parts for the meter accurately, so numerical control machine, homeostat etc. can be used which ensure the quality and crossing-over of every part.


series flow meter is made up of shuck, rotor and arithmometer. Gas entering the inlet of the meter produces a differential pressure within the meter chamber. which causes the impellers to rotate. Timing gears synchronize the impellers to turn in opposite directions .The volume of gas within each measuring chamber hall of displaced by the rotation of each impeller. The rotation of the impellers is translated into specific units of volume (m3) by means of a precision gear train. The volume is in turn, registered on a digital counter.

LLQ series roots flow meter (mechanical)

1. Advantage

• LLQ series roots gas meter is a kind of compact volumetric flow meter designed by Kingnor, widely used in hotels, restaurants, schools, small or medium-size enterprises and institutions. Features
▪ Big Flow Capability, Small Pressure loss, High Accuracy, wide use range.
▪ The rotor, shell’s surface have been special treated, and have high hardness, ensure the meter hardly to be damaged.
▪ Strict dynamic balance test to ensure the stability and the service life of the meter.
▪ DN50(mm),171.5 (mm) of Inlet and Outlet Flange distance (meter scope: LLQ-25~ LLQ85), accelerate the flow efficiency without using pipes. This series of roots flow meter can match threaded screw pipes and sets of flanges, the connection height is 75(mm)( screw height included).
▪ Pulse is directly installed on the counter, output cubic pulse signals, can be used with IC card controller or used for far transmission.

2. Dimensions and Technical Parameters

Status1 Status2 Status 3 Status 4

LLQ-DA series intelligent roots flow meter

A. Features of DTCM intelligent volume calculation instrument

Equipped with the LLQ series roots flow meter with the flow volume calculation instrument designed by Kingnor, can slove the problems created by the changes of temperature and pressure of the gas,and reduce the loss of gas flow. The flow volume calculation instrument can fill the gas flow according to the gas’s temperature and pressure intelligently. It can provide independent electronic headers,or mechanical and electronic headers.

▪Show figures: the instantaneous capacity and accumulation capacity on standard condition,the temperature and the pressure on working conditions,and the battery capacity.
▪ Output:Standard configuration: pulse signal, output signal of IC card controller,RS-485 connect interface. Optional configuration: 4~20mA standard signals
▪ Power: Lithium battery or DC24V power ▪ Explosive-proof grade: Exia IICT4

B:Connection of DTCM intelligent volume calculation instrument
C:Flow conversion
D:Size selection and installment

▪Size graph ▪ Size selection choose the mechanical header flow meter ,when used in direct-measured work condition.
▪ Choose the intelligent flow meter ,when used in high pressure and big flow capability. The reference pressures are listed as follows
▪The tested medium flow capacity should within the usage flow capacity,the usual flow capacity should be limited to 70% of the uppermost capacity.
▪ When there are two or more equipments in use, the maximum flow capacity should be set to all the equipments’ flow capacity multiply the load coefficient,so as to prevent the flow capacity is overload.

E:installation instructions

The user should read this instructions before installation, to ensure the correct installation and the suitable usage, the normal operation and the measurement precision.

▪ Before installation,the inlet and outlet of the flow meter should be clean, in order to prevent the granular impurities fell into the measuring indoor.If the meter’s surface is painted with oil, the user should use the gasoline or the petroleum to clean it,and make sure the pipeline is completely clean,.The upstream of flowmeter should be installed filters, in order to prevent rust slag, weld slag and other impurities get into the measuring room.
▪ when installing the flow meter, regardless the inlet and the outlet is vertical or horizontal, the rotor spool should maintain horizontal.
▪ when the gas pressure fluctuates heavily, the upstream of flowmeter should be installed pressure regulator ,to ensure the accuracy of measurement.
▪ In order to prevent rust slag, weld slag and other impurities get into the measuring room,the user should install filter pipe on the position of the flow meter,after the filter performance for a period of time, and make sure no big impurities exist, the flow meter could be reinstalled. .If the pipeline matches welds, the user should use the filter pipe, the pipeline cannot welded directly with the flow meter. The processing of filter pipe could refer to chart.
▪ when installing the flow meter, we recommend vertical installation,because as the gas flows,the impurities could be cleaned accordingly, and also could improve the serice life and keep the measurement accuracy. Under special circumstances ,the user can choose horizontal installation, the valves and the by-pass piping should be installed to ensure consistent gas flow and easy maintenance.
▪ The size of every pipe must be suitable, when installing the flow meter, make sure the flow meter center does not dislocated, or bear abnormal external force . (inclu ding axial and radial).
▪ After installation, turn off the screw , check whether the rotor can rotate smoothly.If the rotor cannot rotate smoothly ,clean the impurities until it can performance normally,and then turn on the screw.
▪ After installed correctly ,inject the professional oil halfway (Caution : Do not inject fully), when the flow meter is tested periodically, please make sure the lube is clean and enough . when the lube turns black or too much than the normal, please change to the new lube. When the lube too less than the normal , please supply much more lube. (Caution : when supply lube, the front vale and back vale must be closed,after the gas is completely evacuated ,then inject the lube)
▪ When the flow meter operated,first open the bypass valve and the outlet valve. Open the inlet valve slowly, keep it operated in a small volume for a few minutes ,check whether it works normally, when the flow meter is started normally, close the bypass valve gradually and adjust the outlet valve to make it works normally.Caution: opening and closing actions must be slow enough, to prevent the flow meter is damaged by the strong impact of the gas flow. After the flow meter operated for a period of time, if the filter pressure drops heavily , the user should clean or change the media of filter.If the flow meter pressure drops heavily,the user should increase the starting gas flow,and clean the measuring room by gasoline or kerosene

QGG - A series gas filter

We recommend to install a gas filter before the installation of flow meter ,since the flow meter is a kind of volumetric-type meter, the impurity could cause the low measurement accuracy ,or even stuck rotor to effect the gas flow. This filter is convenient to install, easy to maintenance, and eliminate the abnormal external force while installation of the pipeline.

QGG –B series gas filter

QGG - B series gas filter is a new and efficient kind of gas dust removal equipment, and it has become the indispensable gas purification equipment for the gas meter’s safe and reliable operation . This filter has advanced structure, attractive appearance, light weight, high efficiency, easy operation and maintenance, etc.

FM series gas filter

This kind of filter is equipped with the roots flow meter, precision aluminum process, selectable filter nets, avoiding welding slags and impurities get into flow meter ,save the expenses for maintenance or cleaning.



Hot Products
Hot Document
Hot news