What is a Level Sensor? — Transcript

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1. 0:01when you get in your car to go on a
2. 0:03drive you often look at your gas gauge
3. 0:06which is a type of a level sensor
4. 0:08industries use several different types
5. 0:10of level sensors to detect their
6. 0:12products
7. 0:15today we are going to talk about the
8. 0:17different types of level sensors used in
9. 0:19the industry
10. 0:23[Music]
11. 0:33before we get started on today's video
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17. 0:50one
18. 0:52level sensors can be broken into two
19. 0:54classifications point level measurement
20. 0:57and continuous level measuring point
21. 1:01level measurement indicates when a
22. 1:03product is present at a certain point
23. 1:05and continuous level measuring indicates
24. 1:08the continuous level of a product as it
25. 1:11rises and falls
26. 1:12the sensors for point level indication
27. 1:14are capacitance optical conductivity
28. 1:18vibrating or tuning fork and float
29. 1:22switch
30. 1:23the sensors for continuous level
31. 1:25measuring our ultrasonic and radar or
32. 1:28microwave
33. 1:30we will talk about how they work and
34. 1:32which applications are best suited for
35. 1:35their technology as well as their
36. 1:37limitations in certain applications
37. 1:42about point level indication sensors
38. 1:43first starting with capacitance level
39. 1:47sensors
40. 1:48a capacitance sensor is a proximity
41. 1:50sensor that gives off an electrical
42. 1:52field and detects a level by the effect
43. 1:55on its electrical field
44. 1:58these sensors are small less expensive
45. 2:01than other sensors invasive to the
46. 2:03product accurate and have no moving
47. 2:06parts
48. 2:08however they do have to be calibrated
49. 2:10and will only detect certain liquids
50. 2:13capacitance sensors can be used in
51. 2:15liquid storage tanks a water treatment
52. 2:18facility that has storage tanks would be
53. 2:20an ideal use for a capacitance sensor
54. 2:25the next point level sensor we will talk
55. 2:27about is an optical level sensor optical
56. 2:30sensors work by converting light rays
57. 2:32into electrical signals which measure a
58. 2:35physical quantity of light then
59. 2:37translate it into a measurement
60. 2:41these sensors have no moving parts they
61. 2:43are not affected by high pressure or
62. 2:45temperature are small in size and can be
63. 2:48used in liquid applications
64. 2:51however if the lens gets coated or dirty
65. 2:54they would require cleaning
66. 2:57they can be used as low-level indicators
67. 2:59to prevent run dry conditions when using
68. 3:02oil coolant or hydraulics
69. 3:06another style of point level sensor is
70. 3:09conductivity or resistance a
71. 3:11conductivity or resistance sensor uses a
72. 3:14probe to read conductivity the probe has
73. 3:18a pair of electrodes and applies
74. 3:20alternating current to them
75. 3:23when a liquid covers the probe its
76. 3:26electrodes form a part on an electric
77. 3:28circuit causing current to flow which
78. 3:31signals a high or low level
79. 3:35the advantages of using a conductivity
80. 3:37level sensor are there are no moving
81. 3:40parts
82. 3:41they are low-cost and fairly easy to use
83. 3:44the disadvantages are they are invasive
84. 3:47meaning they must touch the product
85. 3:49being sensed they only sense conductive
86. 3:52liquids and the probe will erode over
87. 3:55time
88. 3:57appropriate use for these sensors would
89. 3:59be for signaling high or low levels
90. 4:03vibrating or tuning forks is another
91. 4:06type of point level sensor they use a
92. 4:09fork shaped sensing element with two
93. 4:11tines the fork vibrates at its natural
94. 4:14resonant frequency as the level changes
95. 4:17the frequency of the fork will change
96. 4:19detecting the level these sensors are
97. 4:23cost effective and are also compact they
98. 4:27are invasive to the product meaning they
99. 4:29have to touch the material to sense the
100. 4:31level these sensors are easy to install
101. 4:33and are essentially maintenance-free
102. 4:38have unlimited uses based on the
103. 4:40material that they can sense mining food
104. 4:43and beverage and chemical processing
105. 4:45industries use these sensors for their
106. 4:47applications
107. 4:51the last point level sensor that we will
108. 4:52talk about is a float switch float
109. 4:55switches use a float a device that will
110. 4:58raise or lower when a product is applied
111. 5:00or removed which will open or close a
112. 5:03circuit as the level raises or lowers
113. 5:05moving the float
114. 5:08the advantages of a float switch are
115. 5:10that it is a non powered device it
116. 5:13provides a direct indication and they
117. 5:15are inexpensive the disadvantages are
118. 5:19they are invasive to the product they
119. 5:21have moving parts and can be large in
120. 5:23size float switches will only give an
121. 5:26indication for a high or low level they
122. 5:29cannot measure a variable level a great
123. 5:32use for float switches is in liquid
124. 5:34storage tanks for high or low level
125. 5:37indication
126. 5:39now let's talk about continuous level
127. 5:42measurement sensors we will start with
128. 5:45ultrasonic sensors they work by emitting
129. 5:48and receiving ultrasonic waves the time
130. 5:51it takes for the waves to reflect back
131. 5:53is how distance is measured these
132. 5:56sensors have no moving parts are compact
133. 5:59and reliable
134. 6:02the disadvantage of using this type of
135. 6:04sensor is that they can be expensive and
136. 6:06in some situations the environment can
137. 6:09have a negative effect on them
138. 6:12the benefits of ultrasonic sensors are
139. 6:15that they are non evasive or non-contact
140. 6:18they are unaffected by the properties of
141. 6:20the material they are sensing and they
142. 6:23are self-cleaning because of the
143. 6:24vibrations they give off
144. 6:28an example application is a hot asphalt
145. 6:30tank in a shingle manufacturing plant
146. 6:32the ultrasonic sensor would be placed in
147. 6:35the top of the tank away from the hot
148. 6:37asphalt and used to sense the level in
149. 6:40order to send a fill request for the
150. 6:42tank
151. 6:45radar or microwave is also a continuous
152. 6:49level sensor these sensors transmit
153. 6:51microwaves by an antenna on the radar
154. 6:54sensor
155. 6:56the product that's being sensed reflects
156. 6:58these microwaves back to the antenna and
157. 7:00the time from a mission to reception of
158. 7:03the signal is proportional to the level
159. 7:05of the product
160. 7:07radar sensors are not affected by
161. 7:09temperature pressure or dust they can
162. 7:13also measure liquids pastes powders and
163. 7:16solids they are very accurate and
164. 7:19require no calibration this type of
165. 7:22level sensor is also non-invasive
166. 7:24because it does not have to touch the
167. 7:26product that it is sensing
168. 7:30the disadvantages of radar sensors are
169. 7:33that they are expensive as well as have
170. 7:35a limited detection range if we go back
171. 7:39to our shingle manufacturing plant
172. 7:40example a radar level sensor could be an
173. 7:43ideal solution
174. 7:44much like the ultrasonic sensor radar
175. 7:47sensors are ideal for hot liquid storage
176. 7:50tanks
177. 7:53wrap-up and review what we talked about
178. 7:55today we talked about seven different
179. 7:57types of level switches and their
180. 7:59applications some of their applications
181. 8:02can overlap and when deciding on a
182. 8:04sensor it's important to identify the
183. 8:06product that you are sensing and the
184. 8:08type of feedback that your application
185. 8:10requires
186. 8:13sensors like conductivity or resistance
187. 8:16capacitance float switches and optical
188. 8:19level sensors can be used to indicate a
189. 8:22higher low level while ultrasonic and
190. 8:24radar level sensors can measure your
191. 8:27level to give specific feedback to how
192. 8:29much of a product is in a tank
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197. 8:49[Music]
198. 8:58[Music]
199. 9:07you