Description
The MKS Instruments 153D-26353 is an intelligent downstream exhaust throttle valve assembly featuring an integrated digital PID controller and stepper-motor drive module. Built directly onto a Type 253 butterfly valve chassis, this “Smart” design eliminates the need for an external, rack-mounted controller enclosure. The unit acts as the final control element in a closed-loop vacuum downstream pressure control scheme. By dynamically adjusting the internal flapper position, it modulates system conductance to maintain a precise vacuum chamber pressure independent of process gas inlet fluctuations.
Commercial Availability & Procurement
- Condition: Factory Sealed / New Surplus (or Refurbished, depending on active stock rotation)
- Warranty: 12-Month Mechanical and Electronic Warranty
- Availability: Limited Stock Available / Legacy Semiconductor Component
- Estimated Lead Time: 2–5 business days via worldwide express transport (DHL/FedEx)
- Pricing Policy: Marketplace pricing is determined by supply, demand, and raw flapper sealing metrics. Contact our vacuum components division for a formal, time-stamped quote.
Technical Specifications
The specific configuration code 26353 mandates localized parameters for flange geometry, motor speed, and communication interfaces.
| Parameter | Specification |
| Manufacturer | MKS Instruments |
| Model Type | 153D “Smart” Valve Series |
| Part Number | 153D-26353 |
| Valve Type | Butterfly (Flapper Style) |
| Drive Architecture | Direct mechanical (non-belt) drive with integral cosine generator |
| Control Modes | Closed-loop Pressure Control / Direct Flapper Positioning |
| Control Resolution | Standard 1/10,000 stepper increments |
| Open-to-Close Speed | Standard 7.5 seconds (verify with OEM serial datasheet for sub-2-second override) |
| Differential Pressure Limit | 1 Atmosphere maximum across the flapper (15 psig) |
| External Leak Rate | < 1 × 10⁻⁸ scc/sec Helium |
| Wetted Materials | 316 Stainless Steel (Chassis body) and selected elastomer compounds |
| Maximum Body Temp. | 0 to 90 °C unheated (Verify specific backing o-ring limit) |
| Motor Ambient Temp. | 0 to 70 °C operating environment |
System Integration & Real-World Field Constraints
Closed-Loop Calibration Framework
To execute direct closed-loop downstream pressure control, the 153D-26353 requires an analog input signal from a capacitance manometer (such as an MKS Baratron®). The onboard PID algorithm processes this raw voltage, evaluates the deviation from the user-defined setpoint, and repositions the flapper.
Field Engineering Note: When configuring this loop at 2 AM, standard auto-tuning features can exhibit unstable oscillations if your chamber volume is low or your gas injection rate changes rapidly. Manually adjust the Derivative (
D) and Integral (I) terms inside the software parameters to dampen the overshoot. For processes utilizing reactive gases that form solids upon condensation (e.g., semiconductor CVD or etch applications), you must ensure that the valve body temperature remains above the condensation threshold to prevent mechanical stalling due to byproduct buildup on the flapper edges.
Cosine Generator and Linearization
The mechanical drive contains an integral cosine generator. Because a butterfly valve’s flapper profile does not exhibit a linear relationship between open angle and vacuum conductance, the internal mechanism transforms the uniform stepper motor steps into non-linear spatial positioning. This linearizes the actual pressure change per step, preventing extreme loop gain variations when operating near the fully closed position.
Pinout and Serial Communication Drops
The 153D series utilizes specific multi-pin analog and digital communication ports.
- Cable Routing: Separate high-frequency digital communication wires from local high-power RF generator or plasma matching network cables. RF interference will corrupt the analog pressure feed lines, inducing uncommanded flapper jitter.
- Ground Loops: Ensure the valve chassis is structurally grounded to the main process tool chamber using heavy copper grounding straps. A floating ground baseline will distort the 0–10 V DC Baratron reference signal.
Frequently Asked Questions
Can the 153D-26353 replace a separate 253 valve paired with a 651 controller?
Yes, this is the primary design function of the “Smart” valve series. The 153D-26353 consolidates the processing power of the 651 controller and the actuation of the 253 valve into one integrated unit. This configuration eliminates the lengthy analog interconnect cables that run back to the instrumentation rack, lowering the noise floor of your analog pressure tracking loops. You will need to re-route your transducer and setpoint command cables directly to the valve head assembly.
What is the distinction between flapper positioning mode and pressure control mode?
- Flapper Positioning Mode: Disables the internal PID processing entirely. The valve accepts an external command (via serial link or analog setpoint) and moves the flapper to a fixed percentage of opening (e.g., exactly 45.0% open), disregarding actual chamber pressure. This is typically used during chamber pump-down sequences or vent cycles.
- Pressure Control Mode: Engages the full closed-loop PID stack. The valve monitors the capacitance manometer, compares the data against the target Torr/mbar setpoint, and continuously adjusts the flapper position to maintain stability.
What causes a “Motor Stall” or positioning fault on this unit?
Motor stalling typically results from mechanical obstruction or internal drive assembly wear. Over extended cycles in harsh chemical environments, particulate accumulation or process byproducts can deposit along the internal throat walls. This narrows the operational clearance, causing the flapper to bind as it nears the 0% (fully closed) position. If the internal electronics detect that the stepper motor is dropping steps due to increased torque resistance, it triggers an internal fault flag. Remediation requires extracting the valve body for specialized cleanroom solvent processing or factory re-sealing.
