Design and manufacture of safflower petal harvester machine

Safflower is an oil-seed crop with high quality oil that is used for producing healthy foods and painting colors. This crop has valuable petals which have a lot of uses in medicine, production of food colors and dyes for coloring fabrics, but such problem as dispersion of flowers, thorns of crops that hurt worker’s hands also lack of a suitable harvesting machine have enforced farmers to harvest petals by hand that is a hard work and non-economic. In this study a prototype machine was designed and constructed. This machine includes an engine, a radial fan with BI blades, a snout, a diffuser to separate petals from airflow and a store; all parts are assembled on a trolley to move easily in farm. This machine picks safflower petals out and intakes through snout by the fan suction power. Petals go to diffuser where they are separated from airflow then fall to the store. Velocity of airflow in the snout was determined by a fan test duct in order to design diffuser. At last three farms were harvested by this machine for economic analysis. Results show 657% increasing in amount of harvested petals by harvester machine in comparison with hand harvesting.


Introduction
Safflower (Carthamus tinctorius L.) belongs to the Asteraceae family.It ranks eighth among the major oilseed crop grown worldwide.Safflower is known from antiquity in eastern Mediterranean, India, Egypt, Iran and other Asian countries and North Africa.It is adapted to relatively low rainfall areas receiving winter and spring rainfall with a dry atmosphere during flowering and maturation.It shows considerable resistance to drought and wind [1][2][3][4].
This crop has been cultivated for a long time as the source of red and yellow pigments which are constituents of safflower petals and are used chiefly in coloring food.The dye is called safflower Carmin.Most production is now just for the seed oil (USA), but in Bengal and France it is still grown for the dye [2].
Safflower petals are common aromatic and medicinal herbs with centuries of use [5].Flos carthami, the dried flower petal of safflower is an important crude drug in traditional Chinese medicine for promoting blood circulation and removing obstruction in the channels [6].
The dry weight of petal per plant ranged from 0.2 to 0.8 g with an average of 0.48 g per plant.At the rate of 200 000 plants per ha, 96 kg of plants would be the expected yield [1].Besides mentioned uses for safflower petals, there isn't any suitable machine for harvesting them.Enhance farmers have to harvest petals manually that is slow, expensive and time consuming with high losses.Also worker's hands are injured in contact with crop thrones.
All of these problems make petals harvesting noneconomical, sometimes.So it is decided to design and manufacture a prototype machine for harvesting safflower petals.To find a suitable way for harvesting safflower petals, some similar projects were studied which in following are come.An organization in Iran named, Iran cotton union, has made a machine which harvests cottons by suction force and gathers in a reservoir.It has some snouts which operator places on cottons then machine sucks them off [7].
A vacuum system has been designed for harvesting rangeland and grass seeds from the soil surface or the plant canopy including vacuum harvester head, thresher and cleaner units in Tarbiat Modares University in Iran [8].
An organization in India named NARI (Nimbkar Agricultural Research Institute) has made two types of safflower petal collectors.One of them works by battery energy and is placed on worker's shoulder during harvesting.Another works by a petrol-powered engine and is carried on a trolley.In both, petals are taken off and gathered by suction force and are separated from airflow by cyclone [9].

Philosophy of design
A number of points were considered during the design such as cost of construction, enough suction power, easy moving of machine in farm, separating petals from airflow completely.Also the ability of replacement and fixing of damaged or failure components were considered.

Prototype machine description
The machine comprises five major components assembled together: engine, fan, diffuser, store, and snout.
-Engine: A two stroke internal combustion engine turns the fan and produces suction power.This is a petrol-powered engine with 0.7 kW power and 5500 rpm as maximum rotational speed.Crankshaft is connected to the fan shaft by bolts.
-Fan: A radial fan with 12 steep BI blades was used for producing suction power.This fan has 0.3 m diameter and 0.06 m width.
Fan diameter was 0.3 m, fan speed was 4400 rpm (chosen speed as optimum speed of the fan) and coefficient Ψ 0 was 1.1 for radial fans which come in Table 1.Typical values for flow and pressure coefficients, for all major impeller types, are listed in Table 1 [10].So with these parameters and calculating (Eq.( 1)) static pressure of fan was determined which was 3161 Pa.
Equation ( 2) was used to determine airflow rate of fan [10]: where: Fan width was 0.06 m, fan speed was 4400 rpm, fan diameter was 0.3 m and φ for radial fans was 0.09 (come in Tab. 1).So with these parameters and calculating (Eq.( 2)) airflow rate was determined which was 0.348 m 3 .s−1 .
Equation (3) was used to determine specific speed of fan [10]: where: With calculating (Eq.( 3)) specific speed of fan was determined.
Snout: we used a flexible snout with 0.03 m diameter and 2 m length which is connected to diffuser.Snout loosens the petals and sucks them to diffuser.
The speed of airflow in a duct with 3 cm diameter was determined by an inlet test duct according AMCA (Air Movement and Control Association) test code.
The technical properties of the duct were: diameter of duct was 0.1 m and its the length was 1.05 m, orifice diameter was 0.03 m, the distance between pitot tube to fan inlet was 0.02 m, the distance between straightener and duct inlet was 0.15 m and the its length was 0.45 m.
The dynamic pressure was determined by Pitot tube in 3 orifices and in each orifice at 8 points according "Figure 1" [11].
D is the diameter of the duct which for our duct was 0.1 m.
Diffuser: A space between fan and store that decreases dynamic pressure and airflow velocity subsequently by increasing the area and separates petals from airflow and sends them to store by them weight factor.According to studies the least amount of terminal velocity of safflower petals which was 2.8 m.s −1 in moisture

Table 1 .
Flow and pressure coefficients for various impeller types.