Performance Analysis of Hydraulic Head Box

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Abner Pearson
6 years ago
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1 Performance Analysis of Hydraulic Head Box By: D K Singhal Chandpur Enterprises Ltd., Chandpur , Dist. Bijnor, (Uttar Pradesh), INDIA deveshksinghal@gmail.com deveshksinghal@rediffmail.com Introduction The present article is aimed to evaluate and describe the performance of the hydraulic pressurized headbox supplied by M/S Atreya Industries. Features of Head box Head box is a conventional hydraulic type with PD tank to dampen pulsations generated from the fan pump and pressure screen. A diffuser plate has been provided in the PD tank with step diffuser nozzles in order to create micro turbulence in stock. The manifold is a conventional tapered one with fixed pipes to head box body. Inside the body of the head box, there is a three step step-diffuser block made of SS. To further enhance the function of diffuser block, nylon inserts have been given which result in additional one step making this a four stage step diffuser head box. The slice adjustment is attached with micro setting screws and dial gauges to note down the readings. Page 1

2 Installation The fan pump used is a conventional multivane, back pull type centrifugal pump driven by VFD controlled motor. The piping has been designed at 2m/s flow velocity at maximum flow rate and the slotted pressure screen of 0.25mm slots is again of multi impeller type with 27 vanes to minimize pulsations. The reject of pressure screen is taken to secondary slot type screen with 400X400mm basket and 0.25mm slots. Accepts from secondary screen are taken to fan pump suction and rejects are drained intermittently with a microprocessor controlled timer. The cycle time of reject valve has been set for 15 seconds open and 11 minute close. The slot screen accept line has been directly taken to the bottom inlet of PD tank, with a U bend as indicated in the photograph. The PD tank accept has been taken directly to head box manifold horizontally. Being the head box manifold a tapered one, the recirculation line was not installed. Since the machine is a ground floor one, and the pressure screen is also mounted on the ground floor, the only option available was to have the pressure screen accept line to PD tank having a U bend. A drain valve of 50mm was also given at the bottom of U bend for draining the pressure screen and PD tank. Installation Photos: Slot Screen accept to PD Tank inlet line Page 2

3 PD Tank outlet to head box manifold. A short bend and then straight line. Straight pipe from PD Tank to head box manifold. Page 3

4 Data Collection For data collection, first of all the commissioning was done, and after the machine was stable, a roll of paper was chosen in such a way that there was no process change during this period at least 15 minutes before the roll was taken off. The other parameters are as under- Quality: Deluxe Lottary Printing GSM: 40 Furnish: Waste paper Machine Speed: 210mpm Head: 640mm Fan Pump RPM: 1320 A standard 20X25cm template was used to check gsm of paper. The CD profile was taken by folding the paper along CD, and thus 25X40cm sample was checked for gsm. To ensure correct measurement, a digital balance with 20mg least count was used. This gave an accuracy of 0.2gsm. This template gave 12 samples in CD, and the process was repeated several times to study the process fluctuations in detail. All the samples were immediately checked in order to avoid any change due to moisture evaporation or gain. Page 4

5 Raw Data As obtained, the raw data are as under VAR AVG MIN MAX Avg Diff SD In the above table, we may see that the CD variation is around 1.8gsm, while the individual values vary between 43.4gsm to 46.8gsm. However, the standard deviation for all the individual samples is 0.66, which can be considered as very good. Page 5

6 The maximum, minimum an As indicated in above (ave itself. In fact, due to some 1. If we look at the averag like this. This indicates a gsm roll was of 30 diameter, ( evaluated is 57.6M. This i are 0.68 seconds apart. Th than 1.5Hz (88 pulse per m stable performance of PD

7 If we look at the CD profil We may see that the standard figures at position 7,8,9 and opening the headbox at the d the edges of inserts. Howeve planned that time. There is a which is also affecting the SD To further evaluate the probl predefined value from each o same. This results in compen to time dependent reasons su following plot shows the mo Here, we may see that the SD of 0.2gsm least count balanc normalized data indicates a 0

8 SUMMARY: In summary, we find the following performance indicators from the head box and approach flow system- Basis: Test conditions as described above. Basis Weight: 45 Overall Standard Deviation in gsm: 0.66 Standard Deviation due to head box only: Page 8

Regenerative Braking Application on Rewinder

Regenerative Braking Application on Rewinder By: D K Singhal Chandpur Enterprises Ltd., Chandpur-246725 Dist. Bijnor, (U.P.) INDIA deveshksinghal@rediffmail.com deveshksinghal@gmail.com Sumit Agarwal Shree