- Indicator: Remote Type
- Sensor: Insertion Type
- Quantity: 38 sets (11 for Compressed Air and 27 for Natural Gas Lines)
- Period of Installation and Commissioning: 5 days from Feb 15 to 20, 2011
1. Background
The customer, Pars Khodro is the 3rd largest automobile manufacturer of Iran. It is the first to start manufacturing cars in Iran and is currently assembling 1,200 cars under license of Pride of Kia, Nissan, Peugeot, etc. About 7000 employees are working around the clock 7 days a week. The factory sits on a large estate in the automotive industrial complex on the outskirt of Tehran.
Iran has a vast reservoir of natural resources such as oil and natural gas. They are the world's second largest exporter of natural gas after Russia. Until recently, Iran, as a nation, didn't pay much attention to saving or efficient use of their natural resources. But recent hike in oil and gas prices changed that.
Pars Khodro which is a state-owned company became the first to enforce such change of the nation's attidude towards saving of natural resource. They wanted to start it by accurately measuring their natural gas and compressed air consumptions. For the inital phase, they selected the 38 spots to measure and searched for the sources of flow meters.
But there were limitations. They are that the meters must be installed on existing pipes and that the pipe cannot be closed for sensor installation because the car manufacturing line must be up and running 24 hours a day. The only viable options left were insertion type thermal mass flow meter and the insertion type turbine meter. The turbine type was ruled out because it's mechanical nature gave cause to concern about the explosion for the natural gas line. Of course, turbne types have many disadvantages when compared to thermal mass flow meters, one of them being narrow turndown ratio of 10:1. Thermal mass flow meter's turndown ratio is 100:1 at least. The customer started looking for the suppliers of thermal mass flow meters from all over the world from May 2010. Of course, there are many famous brands such as Kurtz, Fox, Sierra, etc. I don't know whether all of them bid for this project but 2 companies Binder Group of Germany and us, Seil Enterprise Co., Ltd. of Korea were downselected eventually.
The customer fine-tuned the specifications with these 2 companies until the last stage and we ended up wining the contract for the supply, installation and commissioning of 38 sets with our thermal mass flow meter series MST200. I believe our winning points were our good price, versatile interfaces and short delivery.
We delivered a little behind the schedule because there were many upgrade of software 38 sets of model MST200-###-D2-IC-P1-C100 (Remote type with insertion sensor with compression fitting, 220VAC power and 100m sensor cable). The main components, indicator, sensor and the compression fitting as shown as below;
Indicator
Sensor
Compression Fitting
2. Site Condition
I and one of my staff engineers (my brother) flew to the customer's automobile factory in Tehran to install and commission the 38 sets of our MST200 series thermal mass flow meters. Our mission was only to install the insertion sensors and the remote indicators. And putting the sensor cables inside the cable hose and laying the hose between the indicators and the sensors were the job of our local agent and site engineers.
The most of the sensor and the indicator installation spots were outdoors. The pipe sizes ranged from 3" to 12". Where the sensors were to be installed were welded with ball valves, through which the insertion sensor is inserted and fixed. The internal pressures of the pipes were from 3 barg to 7 barg, with those of compressed air a bit higher. Weather-proof boxes were prepared, so that the indicators can be housed inside.
So, the installation task was simple. Insert the sensor on the ball valves, put the indicator inside the weather-proof box and connect the sensor cable to the indicator.
But it was not so simple. When inserting the sensor through the ball valve, we had to open the ball valve, insert the sensor and quickly tighten the nuts of the compression fitting. If the pipe was not pressurized, it could have been done by one person. But because it was pressured with up to 7 barg, we needed 3 persons at least. One to insert the sensor and hold it in position, one to open the valve and hold the valve to stop from turning and the last one to tighten the 2 compression fitting nuts. Because the locations were mostly elevated above the ground by about 5 - 7 meters, it was extremely difficult and dangerous because there was no platform provided. Each person has to use both hands and somehow hold himself, so that he won't fall.
The air and natural gas escaping through the space between the sensor and the valve opening made horrific hiss and it was not at all to hold the sensor from popping out due to the pressure. Air was ok but the natural gas was a totally different thing because they are flammable or explosive. Before we left for Iran, we asked the customer to empty the natural gas lines by purging with inert gas for the safety concern. But the customer couldn't accept it because they cannot stop the production line. At first, the pure though of inserting metallic sensor on the metal pipe (sparks can occur when they collide each other.) sent me chill through my backbone. But I could overcome it and finally got confidence that with a little precaution, that the accident can be avoided. In reality, the gas will be released into the open atmosphere and therefore the gas will quickly get diluted and become very thin. So, if there's no immediate and direct source of fire, the possibility of fire or explosion was very low.
Anyways, it was a good idea to do compressed air lines first. That way we could get the feeling of the pressure and other environment before we do the dangerous gas lines. When we started the first gas line, it was a bit scarry but after this first one, the gas lines were no different from air lines.
The pictures below are for the first 3 sets installed on compressed air lines.
Sensors have been inserted through the ball valves.
The indicators have been put inside the weather-proof boxes.
The sensor has been installed on vertical natural gas pipe outdoors.
Also, the flow meters must have been in place ready to be installed. But that didn't happen either. After one site was finished, we moved to another site. We naturally expect the meters to be there but there was none. So, the site engineer had to drove back to the center and bring it. Then we had to waste for about 30 minutes. Sometimes longer.
The people there were very kind and friendly. When we were busy doing the job out in the cold, one of site engineers used to bring hot kettle of 'Chai', Iranian tea, which was really good and sugar. The tea was really really good and even the sugar. (I bought 5 boxes of this tea at the airport on my way back. It was cheap.). And they were very curious about us, Asians. Wherever we go, the crowds shouted "Niha", "Are you Chinese?", "Hello!"..... Then we say, "We are Koreans.". Then oh, "Park, Jisung!!!" (the famous Koren soccer player of Manchester United.). Also, some popular Korean TV drama figure names such as Jumong, Soseono, Daejangeum, ..... And also the people outside factory was really nice. We went to a regular restaurant outside hotel and they wanted to take pictures with us.
A picture at a restaurant outside hotel
A shot after one site is finished. (I recorded the flow readings for later)
The staff of our agent (Mr. Hossein Kohi) wanted a shot, too.
3. Result of the Work
Though there was some difficulties such as shortage of the tools. We could finish the job in time. Our agent's bringing 2 more helping hands on the last day of the work helped a lot.
The site engineers monitored the flow rate readings of the meters that had been installed. And they said that the meter readings were generally lower than they had expected. I did a presentation on the principle of thermal mass flow meter and explained the difference between the flow rate units of Normal cubic meter per hour (Nm3/h), actual cubic meter per hour (m3/h), standard cubic meter per hour (Sm3/h) and kilogram per hour (Kg/h). They all understood them and realized that our meters were correct. And they gave us thums-up.
4. Future Plan
The 38 sets we installed were for the first phase of the program. The customer has a plan to do the 2nd phase soon and about an equal number of the meters will be required. And they want to tie all of them to a central monitor through network. And we hope that we can build the central monitoring system using our software and networking technology.
5. The Advantages of Thermal Mass Flow Meter
- Thermal mass flow meters are pure solid-state flow meters as opposed to legacy mechanical counterparts such as orifice, rotameter, turbine meters, etc. So, there's less point of failure due to wear and damage.
- With the insertion sensor, the price of the meter won't increase for the increased sizes of the pipes.
- Also with the insertion sensor, you don't have to stop the line for the installation of the sensors. (Of course, you have to stop the line to weld the ball valves. But this can be carefully planned for regular maintenance in advance.)
- The mass flow is measured directly. You don't need pressure or temperature inputs as is the case with orifice types or turbine types.)
- Because the meter is on the electronics basis by definition, it offers versatile output options such as pulse, 4-20mA, alarm, RS-485, etc.
- For more information, you can download the catalog of our MST series thermal mass flow meters from our web, www.maxiflo.co.kr/Cat-Manual/Catalog_ThermalMass.pdf.
This was written by Suh, Sukho of Seil Enterprise Co. (405 Halla Sigma Valley 345-90 Gasan-Dong Geumcheon-Gu Seoul Korea)
